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Filter flow rates and retention times

2009-06-14T13:03:00.009+08:00

Filter requirements and calculations
Calculating ideal flow rates and filter retention times for koi pond filtration systems can sometimes be contradictory and for the average koi keeper with modest stocking levels and a reasonable filter there shouldn't be a problem. But there are a lot of over-stocked ponds with
pretty poor filtration systems - find out why.

Let's get complicated
When it comes to filter sizing, life can get complex. As I've said, if we only wanted simple nitrification, it is probable that filter sizes would be small. However, as well as nitrification koi-keepers want:
# gin-clear' water
# breakdown & removal of DOC,
# conditions which discourage filamentous algae (blanketweed)
# generally optimal water conditions for fish.
In trying to meet these wide-ranging demands filters are built far larger than they would be if based on the required SSA of filter media alone.

The longer the better
Broadly speaking, the effectiveness of biological filtration is improved the longer the 'polluted' water is held in the filter - i.e. the longer the retention time. The most time-consuming process in filtration is the breakdown of dissolved organic carbon compounds into simple inorganic compounds. These compounds are ultimately incorporated back into living organisms. This complex chain of processes is not instantaneous and will, even under ideal circumstances, take some time. If insufficient filtration time is available, intermediate products will be pumped out of the filter back into the pond. This is clearly undesirable and rather defeats the object of having a filtration system. Indeed, this may well be the reason why excessive algal growth occurs in some ponds, with the filter merely producing an endless supply of plant nutrients! So for how long should water be retained in the biological section?
This depends on how polluted the water is in the first place. Certainly, industrial water treatment plants - which handle much higher levels of pollution from sewage etc. - would retain water in the plant for many hours before it was deemed sufficiently clean to return to the
nearest water-course. Given that pond water is likely to be only mildly polluted, a retention time of ten minutes, possibly longer, will usually suffice. The more polluted the water is, the longer it needs to be retained in the filter. Most koi ponds will require a retention time of at least a few minutes. So how do you calculate the retention time of your filter?
This is determined by the flow rate and the volume of water in the filter. If water output from the filter is 2,000 gallons/hour and the filter contains 500 gallons (when full of media) of water then: filter retention time = filter size/pump rate, so, in our example:
retention time = 500 (litres) / 2000 (litres / hour flow rate) = 0.25 hours (which is 15 minutes).
so a given sample of water will take 15 minutes to pass through the filter and back to the pond
In the above, the filter capacity represents the amount of water in the filter - not the physical size of the filter, which will be greater. The retention time or the size of the filter will depend to a
very large extend on the type of filtration medium used. A solid medium with low void space such as gravel will occupy much more filter space than large-pored, lightly packed media and therefore leads to a lower retention time.

More calculations!
Using our same example of a 500 gallon filter. If we now nearly fill it with gravel, the volume of water it will hold will be reduced substantially - maybe to as little as 150 to 200 gallons. Using the above example, the retention time of such a filter would now become;
200/2000 = 0.1 hours (6 minutes) or less This compares the original estimate of a retention time of 15 minutes. In comparison, if the same filter was filled instead with matting or plastic, there would be hardly any displacement and the filter will probably still hold in excess of 450 gallons, giving a retention time over double that of gravel. So a filter with a dense, low-void medium, such as gravel, will need to be substantially larger than one based on light-weight media, in order to achieve the same retention time, which explains why koi filters were traditionally so large. The retention time and therefore the filter size will depend on the filter media used. Cheaper, dense media such as gravel will need larger filters to achieve the same efficiency as lightweight media.

The quicker the better?
Just when everything starts to make sense, along comes a complication. While a longer filter retention time will produce better water quality we also have to consider pond turnover times. Why? Because polluted water is produced in the pond and, if there was a slow turnover at the filter, it would take longer for pond water to get processed by the filter. To make sense of pond turnover rates it is helpful to return to the original analogy of koi being sewage-making machines: expensive food in one end and sewage out the other. Our seemingly impossible aim should be to remove this pollution as fast as it is produced. If we can manage that then we would have perfect water conditions most of the time. When we are considering pollution the primary concern is not so much the volume of water, but rather the number of fish and the amount of food we feed - because this is what determines both the amount of metabolic ammonia and the quantity and quality of solid waste. There are several ways to calculate ammonia production in a koi pond. A rough and ready estimate can be made based on the amount of food fed each day.
Each kilogram of fish food will result, on average, in 37 grams of ammonia being produced, together with copious faeces. And there is other organic waste, such as that from decomposing algae and micro organisms. The important point is that as the stocking, and thereby feeding level, is increased the water will have to be treated at an ever quicker rate if water quality is to be maintained.
# If, for instance, we had a pond of 20,000 litres (4,500 gallons) and the fish were fed 200 grams of food per day, this would produce approximately 7.5 grams (7,500mg) of ammonia per day, an average of say 300 mg per hour. (In reality the ammonia level would fluctuate throughout the day, being highest shortly after feeding).
# At this feeding rate, if no ammonia was removed, at the end of a day the ammonia content of the water would be 24 x 300 mg ammonia = 7 200 mg in 20,000 litres of pond water, giving an ammonia concentration of 0.37 mg/litre, which is too high.
# Conversely, if it was possible to remove the ammonia at the same rate as it is produced - namely, 300 mg per hour - the steady state ammonia level would be zero. To remove ammonia this quickly we would have to pass the entire contents of the pond through the filter every hour,
giving a flow-rate of 20,000 litre/hour, otherwise there will always be some residual ammonia present.
# Deep breath! - If, instead of a flow-rate of 20,000 litre/hour, we had a flow rate of the pond volume every two hours - or half the pond volume every hour (same thing), an oversimplified calculation would give:
# 300 mg ammonia / 20 000 litres (pond volume) x 10000 (flow rate litre/hour) = 150 mg ammonia removed per hour, leaving 150mg in the pond, or a steady state of >0.01 mg / litre. (This makes the simplifying assumption that there is no nitrification occurring in the pond.)
# We can see the effects of increased stocking and / or feeding levels if we take an exaggerated example in which we treble the feeding rate to 600 mgs of food per day 600 grams of food per day would produce around 900 mg ammonia per hour.
With the same flow rate we would remove 900 mg ammonia / 20,000 litres (pond volume) x 10 000 (flow rate litres /hour) = 450 mg ammonia removed per hour leaving 450 mg in the pond, or a steady state of 0.02 mg /litre, an increasingly unacceptable level. Clearly the only way to balance the increased ammonia production would be to 'feed' the ammonia to the filter at an ever increasing rate. I should stress that the above examples are an over-simplification of what actually happens since other factors, such as nitrification in the pond rather than in the filter, also have to be taken into account. Indeed, where the flow rates or filter retention times are less than optimum, an increasing proportion of the ammonia nitrification will take place in the pond rather than the filter. While it is not immediately important where in the system nitrification takes place – it does help to explain why some ponds are more upset as a consequence of disease treatments than others. However, if flow-rates are kept constant and the feeding rate is increased, there will be a steady increase in the background level of ammonia. It is not necessary to get any further involved in calculations, the important point is that when high feeding/stocking levels are involved, the flow-rate is an important factor in determining the ammonia removal rate.

Adequate flow-rate
So what is an adequate flowrate? As explained, it depends on the feeding rate. The most commonly quoted advice is: turn over the volume of the pond between 8 and 12 times a day. But it is important to remember that this is a rule of thumb and flow-rates may well need to be increased for higher feeding and/or stocking rates. Certainly, koi- keepers who feed in excess of 0.25 kg of food per day may have to consider increasing flow rates, particularly if there is a periodic ammonia problem. Conversely, it may be possible to have a slower rate when feeding levels drop, as they do in winter. The pond flow rate is dependent on the total ammonia produced within the system, With higher stocking densities there has to be a corresponding increase in flow rate. In an average koi pond, a flow rate of 1/2 to 1/3 of pond volume per hour should suffice.

Filter size
Taking retention times and flow rates into consideration, when it comes to choosing the right filter size, there are two important but conflicting factors:
# the right filter retention time, which ensures all the required biological activity occurs,
# brisk water flow to prevent a high pond ammonia level. If we decide that a flow-rate of say 10,000 litres per hour (2,200 gal/hour) and a filter retention time of 10 minutes are required then the volume of water in contact with the filter media at any time will need to be;
10,000/60 (minutes) x 10 (minutes retention time) = 1666 litres or 1.6m3.
This means that the filter should be able to hold 1.6 m3 of water after it is filled with media. This is in addition to settlement and spaces below the media trays. The required size of filter will then depend on the media used. Using a high-void medium, such as matting or plastic, we would need a little over 1.6 m3 of media to compensate for the small amount of water displacement, whereas, with a solid medium, we might need at least 3m3 to ensure the same volume of water in contact with the media after displacement. Although this may seem complex, these are the factors which need to be considered to avoid some of the most common filtration problems which often beset koi-keepers - namely, fluctuating water quality, high levels of opportunistic micro-organisms and excessive algal growth. The size of a filtration system becomes more critical as stocking level, and thereby feeding rates, increase. Even when no new fish are added, the continued growth of the existing pond occupants will gradually increase the demand on filter performance. Ideally, what we want is a fairly brisk flow-rate, turning over the pond volume every 1 to 3 hours (depending on feeding and stocking rate) but at the same time a slow, almost imperceptible flow through the filter, allowing sufficient time for the various important biological processes to occur. Water passing through the filter should be in contact with the filter media, and therefore the biofilm, for at least ten minutes, possible longer.

WATER QUALITY

2009-05-25T15:27:00.002+08:00

pH
Why Is it Important?
The pH of a sample of water is a measure of the concentration of hydrogen ions. The term pH was derived from the manner in which the hydrogen ion concentration is calculated - it is the negative logarithm of the hydrogen ion (H+) concentration. What this means to those of us who are not mathematicians is that at higher pH, there are fewer free hydrogen ions, and that a change of one pH unit reflects a tenfold change in the concentrations of the hydrogen ion. For example, there are 10 times as many hydrogen ions available at a pH of 7 than at a pH of 8. The pH scale ranges from 0 to 14. A pH of 7 is considered to be neutral. Substances with pH of less that 7 are acidic; substances with pH greater than 7 are basic.

The pH of water determines the solubility (amount that can be dissolved in the water) and biological availability (amount that can be utilized by aquatic life) of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.). For example, in addition to affecting how much and what form of phosphorus is most abundant in the water, pH may also determine whether aquatic life can use it. In the case of heavy metals, the degree to which they are soluble determines their toxicity. Metals tend to be more toxic at lower pH because they are more soluble.

Reasons for Natural Variation
Photosynthesis uses up dissolved carbon dioxide which acts like carbonic acid (H2CO3) in water. CO2 removal, in effect, reduces the acidity of the water and so pH increases. In contrast, respiration of organic matter produces CO2, which dissolves in water as carbonic acid, thereby lowering the pH. For this reason, pH may be higher during daylight hours and during the growing season, when photosynthesis is at a maximum. Respiration and decomposition processes lower pH. Like dissolved oxygen concentrations, pH may change with depth in a lake, due again to changes in photosynthesis and other chemical reactions. There is typically a seasonal decrease in pH in the lower layers of a stratified lake because CO2 accumulates. There is no light for plants to fix CO2 and decomposition releases CO2.

Fortunately, lake water is complex; it is full of chemical "shock absorbers" that prevent major changes in pH. Small or localized changes in pH are quickly modified by various chemical reactions, so little or no change may be measured. This ability to resist change in pH is called buffering capacity. Not only does the buffering capacity control would-be localized changes in pH, it controls the overall range of pH change under natural conditions. The pH scale may go from 0 to 14, but the pH of natural waters hovers between 6.5 and 8.5.

Expected Impact of Pollution
When pollution results in higher algal and plant growth (e.g., from increased temperature or excess nutrients), pH levels may increase, as allowed by the buffering capacity of the lake. Although these small changes in pH are not likely to have a direct impact on aquatic life, they greatly influence the availability and solubility of all chemical forms in the lake and may aggravate nutrient problems. For example, a change in pH may increase the solubility of phosphorus, making it more available for plant growth and resulting in a greater long-term demand for dissolved oxygen.

Values for pH are reported in standard pH units, usually to one or two decimal places depending upon the accuracy of the equipment used.
Since pH represents the negative logarithm of a number, it is not mathematically correct to calculate simple averages or other summary statistics.
Instead, pH should be reported as a median and range of values; alternatively the values could be converted to hydrogen ion concentrations, averaged, and re-converted to pH values.

Generally, during the summer months in the upper portion of a productive or eutrophic lakes, pH will range between 7.5 and 8.5. In the bottom of the lake or in less productive lakes, pH will be lower, 6.5 to 7.5, perhaps. This is a very general statement to provide an example of the differences you might measure.

The Case of Acid Rain
An important exception to the buffering of pH changes in lakes is the case of lakes affected by acid rain. Lakes that have received too much rain with a low pH (acid rain), lose their buffering capacity. At a certain point, it takes only a small bit of rain or snowmelt runoff for the pH to change. After that point, change occurs relatively quickly. According to the EPA, a pH of 5-6 or lower has been found to be directly toxic to fish.

Turbidity
Why Is it Important?
Turbidity refers to how clear the water is.The greater the amount of total suspended solids (TSS) in the water, the murkier it appears and the higher the measured turbidity. The major source of turbidity in the open water zone of most lakes is typically phytoplankton, but closer to shore, particulates may also be clays and silts from shoreline erosion, resuspended bottom sediments (this is what turns the western arm of Lake Superior near Duluth brown on a windy day), and organic detritus from stream and/or wastewater discharges. Dredging operations, channelization, increased flow rates, floods, or even too many bottom-feeding fish (such as carp) may stir up bottom sediments and increase the cloudiness of the water.

High concentrations of particulate matter can modify light penetration, cause shallow lakes and bays to fill in faster, and smother benthic habitats - impacting both organisms and eggs. As particles of silt, clay, and other organic materials settle to the bottom, they can suffocate newly hatched larvae and fill in spaces between rocks which could have been used by aquatic organisms as habitat. Fine particulate material also can clog or damage sensitive gill structures, decrease their resistance to disease, prevent proper egg and larval development, and potentially interfere with particle feeding activities. If light penetration is reduced significantly, macrophyte growth may be decreased which would in turn impact the organisms dependent upon them for food and cover. Reduced photosynthesis can also result in a lower daytime release of oxygen into the water. Effects on phytoplankton growth are complex depending on too many factors to generalize.

Very high levels of turbidity for a short period of time may not be significant and may even be less of a problem than a lower level that persists longer. The figure below shows how aquatic organisms are generally affected.

Reasons for Natural Variation
Algal turbidity varies seasonally and with depth in a complex manner as discussed previously in response to physical, chemical and biological changes in the lake. Inorganic and detrital particles from the watershed vary largely in response to hydrological events such as storms and snowmelt.

Even relatively small amounts of wave action can erode exposed lakeshore sediments, in this case a minepit lake from northeastern Minnesota. Can you guess what mineral was mined here?

Impacts
The major effect turbidity has on humans might be simply aesthetic - people don't like the look of dirty water. However, turbidity also adds real costs to the treatment of surface water supplies used for drinking water since the turbidity must be virtually eliminated for effective disinfection (usually by chlorine in a variety of forms) to occur. Particulates also provide attachment sites for heavy metals such as cadmium, mercury and lead, and many toxic organic contaminants such as PCBs, PAHs and many pesticides.

Turbidity is reported by RUSS in nephelometric units (NTUs) which refers to the type of instrument (turbidimeter or nephelometer) used for estimating light scattering from suspended particulate material. Turbidity can be measured in several ways. Turbidity is most often used to estimate the TSS (total suspended solids as [mg dry weight]/L) in the lake's tributaries rather than in the lake itself unless it is subject to large influxes of sediments. For the WOW project we will attempt to develop empirical (meaning: based upon direct measurements) relationships between TSS and turbidity for each system since turbidity is easily measured and TSS analyses are not very sensitive at the typically low concentrations found in the middle of most lakes. Also, TSS is a parameter that directly relates to land uses in the watershed and is a key parameter used for modeling efforts and for assessing the success of mitigation and restoration efforts.

What in the world are Nephelometric Turbidity Units (NTU’s)?
They are the units we use when we measure Turbidity. The term Nephelometric refers to the way the instrument estimates how light is scattered by suspended particulate material in the water. The Nephelometer, also called a turbidimeter, attached to the RUSS unit has the photocell (similar to the one on your camera or your bathroom nightlight) set at 90 degrees to the direction of the light beam to estimate scattered rather than absorbed light. This measurement generally provides a very good correlation with the concentration of particles in the water that affect clarity.

In lakes and streams, there are 3 major types of particles: algae, detritus (dead organic material), and silt (inorganic, or mineral, suspended sediment). The algae grow in the water and the detritus comes from dead algae, higher plants, zooplankton, bacteria, fungi, etc. produced within the water column, and from watershed vegetation washed in to the water. Sediment comes largely from shoreline erosion and from the resuspension of bottom sediments due to wind mixing.

Usually, we measure turbidity to provide a cheap estimate of the total suspended solids or sediments (TSS) concentration (in milligrams dry weight/L). TSS measurement requires you to filter a known volume of water through a pre-weighed filter disc to collect all the suspended material (greater than about 1 micron in size) and then re-weigh it after drying it overnight at ~103°C to remove all water in the residue and filter. This is tedious and difficult to do accurately for low turbidity water - the reason why a turbidimeter is often used. Another even cheaper method is to use an inexpensive devise called a Turbidity Tube. This is a simple adaptation for streams of the Secchi disk technique for lakes. It involves looking down a tube at a black and white disk and recording how much stream water is needed to make the disk disappear.
This device yields data for streams that is similar to a secchi depth measurement in lakes. As for secchi measurements are made in the shade with the sun to your back to make an accurate and reproducible reading - the shadow of the observer should be adequate.

Pour sample water into the tube until the image at the bottom of the tube is no longer visible when looking directly through the water column at the image. Rotate the tube while looking down at the image to see if the black and white areas of the decal are distinguishable.
Record this depth of water on your data sheet to the nearest 1 cm. Different individuals will get different values and all should be recorded, not just the average. It is a good idea to have the initials of the observer next to the value to be able identify systematic errors.
If you see the image on the bottom of the tube after filling it, simply record the depth as > the depth of the tube. Then construct a longer tube, more appropriate for your stream.

Turbidity is a standard measurement in stream sampling programs where suspended sediment is an extremely important parameter to monitor. It may also be useful for estimating TSS in lakes, particularly reservoirs, since their useful lifetime depends upon how fast the main basin behind the dam fills with inflowing sediments from mainstem and tributary streams and from shoreline erosion. In the WOW lakes, direct inputs of sediments from tributaries are probably too low to significantly affect the turbidity of the water column out in the main lake. However, algal densities, particularly in the more eutrophic lakes in the Minneapolis Metro area represent enough particulate material to be easily measureable by the RUSS turbidity sensors. Although chlorophyll sensors (fluorometers) would be the best way for us to estimate algal abundance (we lack the funding at present), in these lakes the turbidity sensors provide an alternate estimate of algae.

Why Is it Important?
The secchi disk depth provides an even lower "tech" method for assessing the clarity of a lake. A Secchi disk is a circular plate divided into quarters painted alternately black and white. The disk is attached to a rope and lowered into the water until it is no longer visible. Secchi disk depth, then, is a measure of water clarity. Higher Secchi readings mean more rope was let out before the disk disappeared from sight and indicates clearer water. Lower readings indicate turbid or colored water. Clear water lets light penetrate more deeply into the lake than does murky water. This light allows photosynthesis to occur and oxygen to be produced. The rule of thumb is that light can penetrate to a depth of about 2 - 3 times the Secchi disk depth.

Clarity is affected by algae, soil particles, and other materials suspended in the water. However, Secchi disk depth is primarily used as an indicator of algal abundance and general lake productivity. Although it is only an indicator, Secchi disk depth is the simplest and one of the most effective tools for estimating a lake's productivity.

Reasons for Natural Variation
Secchi disk readings vary seasonally with changes in photosynthesis and therefore, algal growth. In most lakes, Secchi disk readings begin to decrease in the spring, with warmer temperature and increased growth, and continue decreasing until algal growth peaks in the summer. As cooler weather sets in and growth decreases, Secchi disk readings increase again. (However, cooler weather often means more wind. In a shallow lake, the improved clarity from decreased algal growth may be partly offset by an increase in concentration of sediments mixed into the water column by wind.) In lakes that thermally stratify, Secchi disk readings may decrease again with fall turnover. As the surface water cools, the thermal stratification created in summer weakens and the lake mixes. The nutrients thus released from the bottom layer of water may cause a fall algae bloom and the resultant decrease in Secchi disk reading.

Rainstorms also may affect readings. Erosion from rainfall, runoff, and high stream velocities may result in higher concentrations of suspended particles in inflowing streams and therefore decreases in Secchi disk readings. On the other hand, temperature and volume of the incoming water may be sufficient to dilute the lake with cooler, clearer water and reduce algal growth rates. Both clearer water and lower growth rates would result in increased Secchi disk readings.

The natural color of the water also affects the readings. In most lakes, the impact of color may be insignificant. But some lakes are highly colored. Lakes strongly influenced by bogs, for example, are often a very dark brown and have low Secchi readings even though they may have few algae.

Expected Impact of Pollution
Pollution tends to reduce water clarity. Watershed development and poor land use practices cause increases in erosion, organic matter, and nutrients, all of which cause increases in suspended particulates and algae growth.

Secchi disk depth is usually reported in feet to the nearest tenth of a foot, or meters to the nearest tenth of a meter. Secchi disk readings can be used to determine a lake's trophic status. Though trophic status is not related to any water quality standard, it is a mechanism for "rating" a lake's productive state since unproductive lakes are usually much clearer than productive lakes.

Dissolved Oxygen
Why Is It Important?
Like terrestrial animals, fish and other aquatic organisms need oxygen to live. As water moves past their gills (or other breathing apparatus), microscopic bubbles of oxygen gas in the water, called dissolved oxygen (DO), are transferred from the water to their blood. Like any other gas diffusion process, the transfer is efficient only above certain concentrations. In other words, oxygen can be present in the water, but at too low a concentration to sustain aquatic life. Oxygen also is needed by virtually all algae and all macrophytes, and for many chemical reactions that are important to lake functioning.

Reasons for Natural Variation
Oxygen is produced during photosynthesis and consumed during respiration and decomposition.Because it requires light, photosynthesis occurs only during daylight hours. Respiration and decomposition, on the other hand, occur 24 hours a day. This difference alone can account for large daily variations in DO concentrations. During the night, when photosynthesis cannot counterbalance the loss of oxygen through respiration and decomposition, DO concentration may steadily decline. It is lowest just before dawn, when photosynthesis resumes.

Other sources of oxygen include the air and inflowing streams. Oxygen concentrations are much higher in air, which is about 21% oxygen, than in water, which is a tiny fraction of 1 percent oxygen. Where the air and water meet, this tremendous difference in concentration causes oxygen molecules in the air to dissolve into the water. More oxygen dissolves into water when wind stirs the water; as the waves create more surface area, more diffusion can occur. A similar process happens when you add sugar to a cup of coffee - the sugar dissolves. It dissolves more quickly, however, when you stir the coffee.

Another physical process that affects DO concentrations is the relationship between water temperature and gas saturation. Cold water can hold more of any gas, in this case oxygen, than warmer water. Warmer water becomes "saturated" more easily with oxygen. As water becomes warmer it can hold less and less DO. So, during the summer months in the warmer top portion of a lake, the total amount of oxygen present may be limited by temperature. If the water becomes too warm, even if 100% saturated, O2 levels may be suboptimal for many species of trout.

Mid-summer, when strong thermal stratification develops in a lake, may be a very hard time for fish. Water near the surface of the lake - the epilimnion - is too warm for them, while the water near the bottom - the hypolimnion - has too little oxygen. Anoxia forces the fish to spend more time higher in the water column where the warmer water is suboptimal for them. This may also expose them to higher predation, particularly when they are younger and smaller.

Eutrophication exacerbates this condition by adding organic matter to the system which accelerates the rate of oxygen depletion in the hypolimnion. Urban, and other forms of runoff, can also add to this problem very suddenly and dramatically by causing fish kills after excess soils and road hydrocarbons are washed in from intense rainstorms. Conditions may become especially serious during a stretch of hot, calm weather, resulting in the loss of many fish. You may have heard about summertime fish kills in local lakes that likely results from this problem.

In eutrophic and hypereutrophic lakes, summertime fish kills can happen most easily during periods with high temperatures, little wind and high cloud cover. The clouds reduce daytime photosynthesis with its oxygen production and so the DO in the mixed layer. Or even throughout the water column of a shallow unstratified lake, can become critical for fish and other aquatic organisms.

The same basic phenomenon can occur in winter (winterkill) when ice cover removes re-aeration from the atmosphere and snowcover can light-limit algal and macrophyte photosynthesis under the ice. Many lakes in the upper midwest are mechanically re-aerated or injected with air, oxygen or even liquid oxygen to keep ice off of some of the lake and to add oxygen directly to prevent winterkills.

Dissolved oxygen concentrations may change dramatically with lake depth. Oxygen production occurs in the top portion of a lake, where sunlight drives the engines of photosynthesis. Oxygen consumption is greatest near the bottom of a lake, where sunken organic matter accumulates and decomposes. In deeper, stratified, lakes, this difference may be dramatic - plenty of oxygen near the top but practically none near the bottom. If the lake is shallow and easily mixed by wind, the DO concentration may be fairly consistent throughout the water column as long as it is windy. When calm, a pronounced decline with depth may be observed.

Seasonal changes also affect dissolved oxygen concentrations. Warmer temperatures during summer speed up the rates of photosynthesis and decomposition. When all the plants die at the end of the growing season, their decomposition results in heavy oxygen consumption. Other seasonal events, such as changes in lake water levels, volume of inflows and outflows, and presence of ice cover, also cause natural variation in DO concentrations.

Expected Impact of Pollution
To the degree that pollution contributes oxygen-demanding organic matter (like sewage, lawn clippings, soils from streambank and lakeshore erosion, and from agricultural runoff) or nutrients that stimulate growth of organic matter, pollution causes a decrease in average DO concentrations. If the organic matter is formed in the lake, for example by algal growth, at least some oxygen is produced during growth to offset the eventual loss of oxygen during decomposition. However, in lakes where a large portion of the organic matter is brought in from outside the lake, oxygen production and oxygen consumption are not balanced and low DO may become even more of a problem.

The development of anoxia in lakes is most pronounced in thermally stratified systems in summer and under the ice in winter when the water mass is cut-off from the atmosphere. Besides the direct effects on aerobic organisms, anoxia can lead to increased release of phosphorus from sediments that can fuel algal blooms when mixed into the upper euphotic (sunlit) zone. It also leads to the buildup of chemically reduced compounds such as ammonium and hydrogen sulfide (H2S, rotten egg gas) which can be toxic to bottom dwelling organisms. In extreme cases, sudden mixing of H2S into the upper water column can cause fish kills.

Dissolved oxygen concentrations are most often reported in units of milligrams of gas per liter of water - mg/L. (The unit mg/L is equivalent to parts per million = ppm).

DO - % saturation
Oxygen saturation is calculated as the percentage of dissolved O2 concentration relative to that when completely saturated at the temperature of the measurement depth. Recall that as temperature increases, the concentration at 100% saturation decreases. The elevation of the lake, the barometric pressure, and the salinity of the water also affect this saturation value but to a lesser extent. In most lakes, the effect of dissolved solutes (salinity) is negligible; but the elevation effect due to decreased partial pressure of oxygen in the atmosphere as you go up (recall the breathing difficulties faced by Mt. Everest climbers) is about 4% per 300 meters (1000 feet). The DO concentration for 100% air saturated water at sea level is 8.6 mg O2/L at 25°C (77°F) and increases to 14.6 mg O2/L at 0°C.

Electrical Conductivity
Why is it important?
Electrical conductivity (EC) estimates the amount of total dissolved salts (TDS), or the total amount of dissolved ions in the water. EC is controlled by:

1. geology (rock types) - The rock composition determines the chemistry of the watershed soil and ultimately the lake. For example, limestone leads to higher EC because of the dissolution of carbonate minerals in the basin.

2. The size of the watershed (lake basin) relative to the area of the lake (Aw : Ao ratio) - A bigger watershed to lake surface area means relatively more water draining into the lake because of a bigger catchment area, and more contact with soil before reaching the lake.

3. "other" sources of ions to lakes - There are a number of sources of pollutants which may be signaled by increased EC:

a. wastewater from sewage treatment plants (point source pollutants; see: links)
b. wastewater from septic systems and drainfield on-site wastewater treatment and disposal systems (nonpoint source pollutants; see: links )
c. urban runoff from roads (especially road salt; see: links). This source has a particularly episodic nature with pulsed inputs when it rains or during more prolonged snowmelt periods. It may "shock" organisms with intermittent extreme concentrations of pollutants which seem low when averaged over a week or month (see: Measures of Variability Lesson and other links)
d. agricultural runoff of water draining agricultural fields typically has extremely high levels of dissolved salts (another major nonpoint source of pollutants; see: links). Although a minor fraction of the total dissolved solids, nutrients (ammonium-nitrogen, nitrate-nitrogen and phosphate from fertilizers) and pesticides (insecticides and herbicides mostly) typically have significant negative impacts on streams and lakes receiving agricultural drainage water. If soils are also washed into receiving waters, the organic matter in the soil is decomposed by natural aquatic bacteria which can severely deplete dissolved oxygen concentrations (see above).
e. atmospheric inputs of ions are typically relatively minor except in ocean coastal zones where ocean water increases the salt load ( "salinity" ) of dry aerosols and wet (precipitation) deposition. This oceanic effect can extend inland about 50-100 kilometers and be predicted with reasonable accuracy.

4. evaporation of water from the surface of a lake concentrates the dissolved solids in the remaining water - and so it has a higher EC. This is a very noticeable effect in reservoirs in the southwestern US (the major type of lake in arid climates), and is, of course, the reason why the Great Salt Lake in Utah and Mono Lake, California and Pyramid Lake, Nevada are so salty.

5. bacterial metabolism in the hypolimnion when lakes are thermally stratified for long periods of time (in Minnesota this might be May - November depending on the basin shape, lake depth and weather). During this period, there is a steady "rain" of detritus (dead stuff, mostly algae and washed in particulate material from the watershed) down to the bottom. This material is decomposed by bacteria in the water column and after it reaches the sediments. Their metabolism releases the potential energy stored in the chemical bonds of the organic carbon compounds, consumes oxygen in oxidizing these compounds, and releases carbon dioxide (CO2) after the energy has been liberated (burned). This CO2 rapidly dissolves in water to form carbonic acid (H2CO3), bicarbonate ions (HCO3- ) and carbonate ions (CO3-) the relative amounts depending on the pH of the water. This newly created acid gradually decreases the pH of the water and the "new" ions increase the TDS, and therefore the EC, of the hypolimnion. Essentially, they are "eating" organic matter much as we do and releasing CO2. We oxidize organic carbon using O2 that we breathe out of the air as an oxidant. We use the energy to drive our metabolism and exhale the oxidized carbon as CO2. The oxygen is simultaneously chemically reduced and exhaled as water vapor (H2O; the oxidation state of gaseous molecular oxygen is reduced from 0 to -2 in the process). Other higher aquatic organisms that have aerobic metabolisms, such as zooplankton, insects and fish also consume oxygen dissolved in the water while releasing carbon dioxide as they metabolize organic carbon (food items).

What in the world are microSiemens per centimeter (µS/cm)?
These are the units for electrical conductivity (EC). The sensor simply consists of two metal electrodes that are exactly 1.0 cm apart and protrude into the water. A constant voltage (V) is applied across the electrodes. An electrical current (I) flows through the water due to this voltage and is proportional to the concentration of dissolved ions in the water - the more ions, the more conductive the water resulting in a higher electrical current which is measured electronically. Distilled or deionized water has very few dissolved ions and so there is almost no current flow across the gap (low EC). As an aside, fisheries biologists who electroshock know that if the water is too soft (low EC) it is difficult to electroshock to stun fish for monitoring their abundance and distribution.

Up until about the late 1970's the units of EC were micromhos per centimeter (µmhos/cm) after which they were changed to microSiemens/cm (1 µS/cm = 1 µmho/cm). You will find both sets of units in the published scientific literature although their numerical values are identical. Interestingly, the unit "mhos" derives from the standard name for electrical resistance reflecting the inverse relationship between resistance and conductivity - the higher the resistance of the water, the lower its conductivity. This also follows from Ohm’s Law, V = I x R where R is the resistance of the centimeter of water. Since the electrical current flow (I) increases with increasing temperature, the EC values are automatically corrected to a standard value of 25°C and the values are then technically referred to as specific electrical conductivity.

All WOW conductivity data are temperature compensated to 25°C (usually called specific EC). We do this because the ability of the water to conduct a current is very temperature dependent. We reference all EC readings to 25°C to eliminate temperature differences associated with seasons and depth. Therefore EC 25°C data reflect the dissolved ion content of the water (also routinely called the TDS or total dissolved salt concentration).

How much salt is there in lakewater?
The image below was developed to give you an idea of how much salt (dissolved solids and ions) is present in some of the WOW lakes and to compare them to a range of other aquatic systems. TDS, in milligrams per liter (mg/L) stands for total dissolved salts or solids and is the weight of material left behind were you to filter a liter of water to remove all the suspended particulates and then evaporate the water from the container (usually done in a drying oven in the lab unless you work on Lake Mead in southern Nevada where you can just set it outside for a few minutes in the summer). Each of the piles represents the amount of salt present in a liter of water. We used sodium bicarbonate (baking soda) for the lakes and sodium chloride (table salt) for the ocean.

Chlorophyll - A Measure of Algae
An in-depth microscopic enumeration of the dozens of species of algae present in a water column each time a lake is sampled is prohibitively costly and technically impossible for most monitoring programs. Further, in many lakes a large portion of the algal biomass may be unidentifiable by most experts (these are appropriately called LRGTs or LRBGTs -- little round green things and little round blue-green things). However, measuring the concentration of chlorophyll-a is much easier and provides a reasonable estimate of algal biomass. Chlorophyll-a is the green pigment that is responsible for a plant's ability to convert sunlight into the chemical energy needed to fix CO2 into carbohydrates. To measure chlorophyll-a, a volume of water from a particular depth is filtered through a fine glass-fiber filter to collect all of the particulate material greater than about 1 micron (1/1000th of a millimeter) in size. The chlorophyll-a in this material is then extracted with a solvent (acetone or alcohol) and quantified using a spectrophotometer or a fluorometer.

Both chlorophyll-a and secchi depth are long-accepted methods for estimating the amount of algae in lakes. Secchi depth is much easier and less expensive to determine. However, care must be used in interpreting secchi data because of the potential influence of non-algal particulate material, such as silt from stream discharge or re-suspended bottom sediment. Also, the tea color of some lakes that's due to dissolved organic matter from bogs, can have an effect on secchi depth readings as well. Even if chlorophyll-a is measured, it may be important to also examine the algal community microscopically on occasion, since the mix of species may influence lake management decisions.

Temperature
Why Is it Important?
Most aquatic organisms are poikilothermic - i.e., "cold-blooded" - which means they are unable to internally regulate their core body temperature. Therefore, temperature exerts a major influence on the biological activity and growth of aquatic organisms. To a point, the higher the water temperature, the greater the biological activity. Fish, insects, zooplankton, phytoplankton, and other aquatic species all have preferred temperature ranges. As temperatures get too far above or below this preferred range, the number of individuals of the species decreases until finally there are few, or none. For example, we would generally not expect to find a thriving trout fishery in ponds or shallow lakes because the water is too warm throughout the ice-free season.

The Q10 Rule
Changes in the growth rates of cold-blooded aquatic organisms and many biochemical reaction rates can often be approximated by this rule which predicts that growth rate will double if temperature increases by 10°C (18°F) within their "preferred" range.

Q10 rule
Temperature is also important because of its influence on water chemistry. The rate of chemical reactions generally increases at higher temperature, which in turn affects biological activity. An important example of the effects of temperature on water chemistry is its impact on oxygen. Warm water holds less oxygen that cool water, so it may be saturated with oxygen but still not contain enough for survival of aquatic life. Some compounds are also more toxic to aquatic life at higher temperatures. Temperature is reported in degrees on the Celsius temperature scale(C).

Reasons for Natural Variation
The most obvious reason for temperature change in lakes is the change in seasonal air temperature. Daily variation also may occur, especially in the surface layers, which are warm during the day and cool at night. In deeper lakes (typically greater than 5 m for small lakes and 10 m for larger ones) during summer, the water separates into layers of distinctly different density caused by differences in temperature. Unlike all other fluids, however, as water approaches its freezing point and cools below 4°C, the opposite effect occurs and its density then begins to decrease until it freezes at 0°C (32°F). This is why ice floats. This process is called thermal stratification. The surface water is warmed by the sun, but the bottom of the lake remains cold. You can feel this difference when diving into a lake. Once the stratification develops, it tends to persist until the air temperature cools again in fall. Because the layers don't mix, they develop different physical and chemical characteristics. For example, dissolved oxygen concentration, pH, nutrient concentrations, and species of aquatic life in the upper layer can be quite different from those in the lower layer. It is almost like having two separate lakes. The most profound difference is usually seen in the oxygen profile since the bottom layer is now isolated from the major source of oxygen to the lake - the atmosphere.

When the surface water cools again in the fall to about the same temperature as the lower water, the stratification is lost and the wind can turbulently mix the two water masses together because their densities are so similar (fall turnover). A similar process also may occur during the spring as colder surface waters warm to the temperature of bottom waters and the lake mixes (spring turnover). The lake mixing associated with a turnover often corresponds with changes in many other chemical parameters that in turn affect biological communities. Watch for these changes in your lake this fall and spring.

Because light deceases exponentially with depth in the water column, the sun can heat a greater proportion of the water in a shallow lake than in a deep lake and so a shallow lake can warm up faster and to a higher temperature. Lake temperature also is affected by the size and temperature of inflows (e.g., a stream during snowmelt, or springs or a lowland creek) and by how quickly water flushes through the lake. Even a shallow lake may remain cool if fed by a comparatively large, cold stream.

Expected Impact of Pollution
Thermal pollution (i.e., artificially high temperatures) almost always occurs as a result of discharge of municipal or industrial effluents. Except in very large lakes, it is rare to have an effluent discharge. In urban areas, runoff that flows over hot asphalt and concrete pavement before entering a lake will be artificially heated and could cause lake warming, although in most cases this impact is too small to be measured. Consequently, direct, measurable thermal pollution is not common. In running waters, particularly small urban streams, elevated temperatures from road and parking lot runoff can be a serious problem for populations of cool or cold-water fish already stressed from the other contaminants in urban runoff. During summer, temperatures may approach their upper tolerance limit. Higher temperatures also decrease the maximum amount of oxygen that can be dissolved in the water, leading to oxygen stress if the water is receiving high loads of organic matter. Water temperature fluctuations in streams may be further worsened by cutting down trees which provide shade and by absorbing more heat from sunlight due to increased water turbidity.

REFERENCES
Michaud, J.P. 1991. A citizen's guide to understanding and monitoring lakes and streams. Publ. #94-149. Washington State Dept. of Ecology, Publications Office, Olympia, WA, USA (360) 407-7472.
Moore, M.L. 1989. NALMS management guide for lakes and reservoirs. North American Lake Management Society, P.O. Box 5443, Madison, WI, 53705-5443, USA (http://www.nalms.org).

Mahseer/Kelah

2009-03-12T14:21:00.043+08:00

INTRODUCTION
Mahseer is acclaimed as a world famous outstanding game and food fish of India. As a sport fish, it provides unparalleled recreation to anglers from all over the world, better than salmon. It is known as tiger in waters, because of the fight it musters to wriggle off the hook. Anglers come to the Cauvery River in southern India in search of these mighty mahseer.In Northern Europe, you have the leaping salmon. In Russia and Mongolia, you have the ferocious taimen. In North America, the inscrutable muskellunge. And in South America, the humongous arapaima. These are some of the biggest and most challenging river fish you can find and international anglers are willing to pay big money to pit wits with them. In parts of South and South-East Asia, there is a large-scaled fish that can match or even surpass the strength and stamina of these fish.

For some, this fish has no equal. Half carp and half barbell, it thrives in the fast currents of rocky rivers, and can shoot up tall rapids and even small waterfalls. When hooked by an angler, it can fight for hours before it succumbs – if the angler is lucky enough not to have his line broken or hook straightened out!

In the past, mahseer formed a substantial natural fishery in the major riverine and lacustrine ecosystems of India. In commercial fisheries it occupies an important position for its good quality. For the fishermen mahseer is of considerable importance because of its large size. As a food fish, it is highly esteemed and fetches the high market price. The mahseer (tor tambroides’ and ‘tor Douronensis), known in Malaysia as ikan kelah - Red Finned Mahseer, Ikan Kelah Merah/ Merah Bara from Pahang/Terengganu and Ikan Kelah Merah Rebung from Kelantan, Semah/ Empurau from Sarawak, Pelian from Sabah, Kelah Hijau/ Kejor/Tengas - Malaysian, Semah/ Garing from Sumatra Indonesia, Blue Thai Mahseer from Thailand, Golden Burmese from Burma. In the Mekong basin lives the Chinese Mahseer (Tor sinensis). In India and Myanmar, you have the Golden Mahseer (Tor putitora and Tor tor)are large cyprinids inhabiting the clear, pristine and fast flowing waters of Asia, from the cool waters of Himalayan streams to the tropical rivers of South East Asian jungles. Rapid development in the watersheds within the natural range of many Tor species habitats, particularly the spawning grounds, is increasing pressure and threatening their survival. This has resulted in depletion of natural stocks and consequently some species have become rare, threatened and/or endangered. In view of their conservation value and the aquaculture potential, there are concerted efforts amongst researchers, developers, planners and conservationists and governments all across Asia to enhance the natural populations in rivers and natural water bodies.
Day (1878) believed that mahseer constituted only one species. Hora (1940) confirmed the validity of six different species. A recent critical study on the subject by Menon (1992) confirmed 6 valid species. He has, however, described a new species from the Darna River (Godavari drainage) at Deolali, Nashik District of Maharashtra, and named it Tor kulkarnii, which he describes as a dwarf cognate of Tor khudree. Preserntly seven valid species are recognized for India:

Scientific Name ....................... Common Name

Tor putitora (Ham.) -------------- Golden or putitora mahseer
Tor tor (Ham.) ------------------- Turiya or tor mahseer
Tor khudree (Sykes) -------------- Deccan or khudree mahseer
Tor mussullah (Sykes) ------------ Humpback or mussullah mahseer
Tor kulkarnii ---------------------- Dwarf mahseer
Tor progeneius (McClelland) ------- Jungha of the Assamese
Tor mosal (Sykes) ---------------- Copper or mosal mahseer

In addition to the above, three sub-species, viz., Tor mosal mahanadicus, Tor khudree malabaricus and Tor khudree longispinis are considered by Desai (2002) as valid species, with some reservations. Different species of mahseer occupy different ecosystems ranging from tropical waters where summer temperatures reach 35°C, to sub-Himalayan regions, where the temperatures fall to 6°C. Similarly, they occur in streams hardly above sea level and are also found at an altitude of 2000 m above sea level. Jhingran and Sehgal (1978) remarked that the occurrence and distribution of mahseer is controlled by the prevailing water temperature of the streams and not by the altitude.

Mahseers were considered as carnivorous and slow growing and thus unsuitable for fish culture. However, a careful study of the feeding habits of mahseer indicating that it is omnivorous has dispelled the notion that mahseer are carnivorous. Studies on the anatomical adaptations of the alimentary canal system also confirm that mahseer are omnivorous. Tripathi (1995) suggested the inclusion of mahseer in polyculture, cage culture and for river ranching and has stated that mahseer would not compete with mrigal (Cirrhinus mrigala) and the common carp. The importance of mahseers as a World-famous game fish is well known. The group comes in a spectrum of colours from deep burnt copper, through gold, silver, dark black, and inhabit different rivers through out the length and breadth of India, Pakistan, Burma, Bangladesh Srilanka, and even Thailand, (Thomas, 1897). Among the seven different recorded species (viz. Tor putitora, T. mussulah, T.khudree, T mosal, T. progeneius, T. tor and Acrossocheilus hexangonolepis). Tor putitora or golden mahseer is one of the most-sought after species providing the main fishery in the uplands all along the Himalayan belt extending from Kashmir in the north-west to Sadiya in the north-east. The fish is also known as Greyhound or the thick-lipped mahseer and has been observed to attain the weight of 70-80 kg. (Misra, 1962). Anglers regard golden mahseer as one of the finest sport-fish and it is a source of recreation to innumerable sportsmen both Indian & Foreigner Thomas, 1897 in his famous book " The Rod in India" stated that pound for pound mahseer is far superior to ‘lordly salmon’ in sporting qualities. To the local fishermen too, mahseers have been of considerable importance because of their large size, hardy texture, high commercial value and longer shelf life.

In recent years due to their proximity to human intervention, mahseer stock is threatened with multifaceted dangers posed by construction of series of dams, barrages/ weirs across the rivers on one hand and over-exploitation on the other. While uncontrolled fishing and destructive fishing devices have adversely affected the riverine population, the construction of dams are acting as physical barrier to this migratory species, tending to prevent their access to their usual breeding and feeding grounds. Dams interrupt the river continuum and block the longitudinal connectivity of rivers. They also generate a complex web of impacts which affect the physical and biological components of the riverine environment. The denial of migration also results in permanent and irrevocable eradication of fish stock ranging from depletion to complete extermination. The ever-diminishing catches of mahseer from the river Satluj, Giri, Beas, Chenab and their tributaries clearly bespeaks the affects caused by the construction of Pandoh, Chamera, Pong, Bhakra & Giribata barrages. Regardless of their height, weirs and dams constitute barriers to breeding migration of mahseer. Further, mahseer population is also affected by morphological modifications resulting from completion of river valley projects. These include change in slope, river-bed profile, submersion of gravel zones or riffle section as well as destruction of riparian vegetation and changes in tropic regimes. Most of the negative factors affect upper parts of the streams where lacustrine conditions are superimposed on the river. Downstream, the hydrological conditions get severely altered through reduction of water discharge. The adverse conditions of the flow can extend over many kilometers downstream of the obstruction so that fish passages become difficult.

Indiscriminate hooking, netting, dynamiting and electrocuting have also greatly affected the mahseer availability in the State’s rivers and streams. In the pursuit of more and more catches, even the declared State’s sanctuaries have not been spared by the poachers. Further, due to reduced availability of large mahseer in the streams, fishing pressure on juveniles is on the increase with the result that streams earlier assuring a bountiful harvest have started giving a dismal picture. The various anglers’ Associations have painted a similar picture of other States of the country. Once teeming with thousands of mahseer, streams like Giri, Ashwani, Binwa Neugal, Beas, etc. the returns are sharply declining, raising the number of disgruntled anglers each year. Mahseer is known to be an omnivore fish in its adult stage. In earlier days considering the mouth opening and massive size, the fish was supposed to be a carnivore (Malhotra, 1982).

However, we have collected many samples from rivers of Pokhara Valley, where gut contained rice grain, small insects and plants. Mahseer therefore appears to be an opportunistic feeder which feeds on a wide variety of food of plant and animal origin. Mahseer have been found to also feed on green filamentous algae, insect larvae, small molluscs, and algal coatings on rocks (Shrestha, 1997; Negi, 1994; Dubey, 1985). Nautiyal and Lal (1984) reported that in natural habitat food of mahseer fingerlings consisted of insect matter (81.4 percent), plant matter (15.9 percent) and other items including fish (1.6 percent). Knowledge of natural feeding habits of mahseer would provide a basis for formulated feed development for this species. Studies on nutrition and feed management for different developmental stages of mahseer are a prerequisite for farming possibilities of this high value native species. Despite their abundance at one time, the mahseer population has been declining in number and size in natural waters and is in serious danger of extinction. The National Commission on Agriculture (1976) in its report on fisheries had stated there was a general decline in mahseer fishery in India due to indiscriminate fishing of brood and juvenile fish and the adverse effect of the river valley projects and accordingly suggested extensive survey and detailed biological investigation on this alarming situation.

The biological investigations commenced in 1970 in Pune District of Maharashtra under the guidance of C.V. Kulkarni and eventually yielded very significant information on artificial propagation of mahseer. The downward trend in the commercial and sport fishing catches of mahseer due to various man-made and ecological factors could be obviated by a continuous stocking programme on a large scale and by strictly enforcing the prevailing legislation. This programme would require production of fry and fingerlings of this species on a very large scale and their release in depleted natural perennial waters. During the last three decades of the 20th century extensive studies on the distribution, biology and fishery of the commercially important mahseers have been made by TPCL. This has led to development of techniques of breeding, larval rearing and cultural practices at TPCL hatchery farm Lonavla, which is now capable of producing fry and fingerlings of all the desired species of mahseer. The mahseer hatchery technology developed by TPCL may well lead to the revival of mahseer fisheries in Indian waters, provided standardised simple mahseer hatcheries based on TPCL technologies could be set up in the rural areas adjacent to rivers and reservoirs.

Causes of depletion. The exponential increase in human population is the root cause for the loss of biodiversity and the depletion of natural resources. Much has already been said regarding the depletion of mahseer. The major possible factors for the depletion of mahseer stocks are:

degradation of ecological conditions of aquatic systems,
indiscriminate fishing of broodstock and juveniles,
impacts of river valley projects,
industrial and human pollution,
the use of explosives, poisons and electrofishing by poachers,
introduction of exotic species,
population pressures on resources.

The above- mentioned factors combined with human greed are responsible for the reckless damage to this priceless national heritage. The declining trend in the populations of mahseer needs immediate attention for its in situ conservation and rejuvenation in natural waters. The reasons for the conservation of this gene pool need no further emphasis. Several measures have been enumerated for their conservation (Kulkarni 1991; Ogale, 1997). The artificial propagation and distribution of resultant fry and fingerlings into different waters constitutes one of the most important steps to rehabilitate the species, as is being done for the well known salmon in American and European waters. However, for dependable and continued results, improved aquacultural practices for the breeding of mahseer under controlled conditions play a vital role.

The "kelah" or Golden Mahseer - takes three years to grow to a size of three kilogram! To grow to 8 kg would take some 40 years, depending on its environment and food sources. The kelah (scientific name "Tor Tombroides") which is also known as the "empurau" in Sarawak and Mahseer in India. Tor douronensis (Valenciennes, 1842), also known as blue kelah, are found in Thailand east to Vietnam and south to Indonesia. The other common name for this fish depending on the region/location it is found, are khela mahseer (or river carp) /Garing/ Semah/ Pelian - Indonesia. The kelah hijau is usually a tengas daun, a smaller sub-species of tengas, tengas can grow up to 5kg ..the biggest kelah was about 25kg ..caught in kenyir lake many many years ago. A fish of 50 kilograms is now considered a rarity with the average being more in the 5 to 10 kilogram range. Unfortunately, poachers have found Mahseer catches to be lucrative and many of the best fish end up in their traps and nets rather than on an angler's line. With large fins and a tendency to fight with rather than against the current gives Golden Mahseer the reputation of being amongst the most powerful freshwater fish. There are many stories of anglers being taken by surprise and ending up in the water with their rod, or only just saved by an attentive local guide. Other stories suggest that one of the best tactics for coping with the fishes initial run is to sprint downstream rod in hand. The kelah is one of Malaysia’s precious ecological heritage; a ﬁsh that is unique to the region. It is of very high economic value too. The prize fish which can fetch RM100 per kg, is now scarce as its population has dwindled either because of over-fishing or destruction of its habitat brought about by erosion. Anglers would have to persistent enough to trek into the upper reaches of the rivers to hunt for this game fish that foreigners call the "Malaysian Golden Mahseer". Among the places where anglers still go for the thrill of landing the fish are certain pools in the rivers of Taman Negara near Jerantut, like Sungai Tahan, Sungai Kenyam and Sungai Tembeling. Sungai Nenggiri in Gua Musang is also a haven for these much sought after freshwater fish that can fetch a good price at fine dining restaurants in the country. Sadly these Malaysian masheer (or tambriodes) faces extinction and efforts are underway to protect this endangered species. Anglers and eco-tourists are willing to pay signiﬁcant sums of money to meet this ﬁsh! The kelah is essentially a carp, placed in the order of Cypriniformes, although it is loosely related to the European barbel (Barbus barbus).. It’s closer relatives are the mahseer species of India (Tor spp.) and several other countries in Asia. You could say that kelah is amember of Asia’s prime sport ﬁshes. Kelah can be found in the mighty rivers of Malaysia: Sungai Pahang and its tributaries (Tembeling, Jelai, Tanum, Tahan, Keniam, Sat etc), S. Perak and its tributaries (Kejar, Chiong, Singor, Temengor), Sg. Muda and its tributaries (Teliang, Gawi), the rivers feeding Lake Kenyir (Petuang, Cacing, Terenggan, Tembat), Sg. Kelantan and its tributaries (Galas, nenggiri, Lebir, Aring, Pertang), The Endau-Rompin rivers (Endau, Kincin, Kemapan, Jasin, Mas, Lemakuh), and the Batang Rajang and Sg Kinabatangan systems. In fact, almost all the major rivers in the country – with the exception of Perlis – used to have stocks of this beautiful ﬁsh.
Golden Mahseer are omnivorous, feeding on plant matter and insects as juveniles and becoming more predatory as they get larger. Anglers will find a live or dead bait or a lure delivered in the bottom half of the water to work the best. Where possible, fishing from a boat is recommended as the biggest fish stay out where the current is strong. A boat also allows for a stretch of river to be covered easily - a big issue up in the mountains where the riverbanks may be very difficult to traverse.

Ikan Keli/Catfish

2009-03-03T21:37:00.004+08:00

PENGENALAN

Ikan keli termasuk didalam keluarga Clariidae. Ia berbeza dari jenis2 ikan berduri yang lain daripada Ictaluridae saperti Ictalurus spp.(Channel catfish), keluarga Schilbeidae(Pangasidae) saperti ikan patin(Pangasius sp) dan keluarga Bagridae saperti ikan baung(Mystus sp). Dua spacies keluarga Clariidae yang biasa dikenali dinegeri ini ialah keli bunga, Clarias macrocephalus dan keli kayu, Clarias batrachus.
Ikan ini berupaya untuk hidup didalam perbagai keadaan dan mutu air. Ia hanya memerlukan kawasan ternakan yang kecil untuk diternak dan boleh distok lebih padat dari kebanyakan species lain. Ia boleh hidup diatas darat untuk beberapa jam atau didalam air yang rendah kandungan oksigen terlarut kerana ia mempunyai organ arboresen yang membolehkannya bernafas udara selagi alat pernafasan ini masih lembab.
Ikan keli eksotika/Afrika, Clarias gariepinus/lazera dan kacukan C.macrocephalus dan Clarias gariepinus telah mula diperkenalkan dari negara jiran pada tahun 1988 dan kini telah menjadi species utama ternakan dinegara kita.

Asas Ikan Keli
Ikan keli mempunyai misai yang terletak berdekatan dengan hidung. Ia berfungsi sebagai alat pengesan ketika bergerak dan mencari makanan. Ia juga mempunyai alat pernafasan tambahan yang disebut ‘arborescent organ’ yang tumbuh pada insang kedua dan keempat, sehingga ikan keli boleh bernafas menggunakan oksigen dari udara bebas. Warna tubuhnya di mana terdapat ikan keli yang berwarna perang gelap dan perang terang, malah terdapat juga yang berwarna hitam. Ketika larva baru menetas, ia berukuran sekitar 3.4mm dan lebar mulutnya lebih kurang 0.28m. Setelah ia berusia 7 hari, sirip dada akan tumbuh sepanjang 7mm dan sirip perutnya berukuran 14.9mm. Larva akan mencapai bentuk yang sempurna apabila pembesaran yang jelas di antara sirip punggung, ekor dan anus yang akan kelihatan pada hari ke-22 dan panjangnya adalah 24.4mm.
Ikan keli mempunyai sengat yang menjadikannya adalah sangat berbisa. Jika terkena sengatan ikan keli ini kesannya sedikit gatal dikawasan gigitan. Berdasarkan Weber de Beaufort(1965) ikan keli diklasifikasikan sebagai berikut;
Filum : Chordata, binatang bertulang belakang.
Kelas : Pisces, mempunyai insang
Ordo : Ostariophysi, ikan yang mempunyai tulang pada bahagian atas sebagai alat pelengkap keseimbangan.
Subordo : Siluroidae, berbentuk panjang dan tidak bersisik.
Keluarga : Clariidae, ikan yang memiliki cirri khas dengan bentuk kepala pipihbertulang keras, sirip dada dilengkapi dengan sengat sebagai senjata dan alat Bantu untuk bergerak serta memiliki alat pernafasan tambahan dimana ia boleh menghirup oksigen dari udara bebas.
Genus : Clarias
Spesis : Clarius batrachus.

Syarat – syarat kehidupan
Ikan keli hanya hidup di kawasan air tawar sahaja. Ikan keli boleh hidup di kawasan dataran rendah dan dataran tinggi hingga ketinggian 700m pada paras laut. Ikan keli dapat dipelihara di perairan rendah kandungan oksigennya seperti di dalam parit, kolam atau tempat takungan lebihan air. Ini disebabkan olet alat pernafasan tambahan yang ada pada ikan keli membolehkannya bernafas menggunakan oksigen dari udara bebas. Malah ikan ini juga tahan kepada bahan-bahan organik.

Cara hidup ikan keli
1. Ikan keli bersifat karnivor iaitu pemakan daging. Ia boleh memakan sisa-sisa dari sisa domestik dan sisa industrial. Selain itu ikan keli juga boleh memakan kotoran dan bahagian lebihan ayam seperti perut dan usus.
2. Secara semulajadi makanan ikan keli terdiri daripada mikro organisma seperti kutu air iaitu Daphnia, Cladocera dan Copepoda. Ikan keli juga memakan pelbagai jenis cacing, jentik-jentik atau siput-siput kecil. Bagi ikan keli yang dipelihara makanan seperti palet diberikan.
3. Ikan keli suka bersembunyi di dalam lubang-lubang yang terdapat di dalam perairan. Lubang tersebut bukan sahaja menjad tempat persembunyian malah sebagai tempat untuk bertelur. Ikan keli lebih gemar akan perairan bersih dan baru di mana ikan-ikan tersebut akan berkumpul di pintu kemasukan air semasa proses penukaran air kolam pemeliharaan.
4. Benteng kolam yang tinggi tidak menjadi halangan bagi ikan keli untuk keluar dari kolam kerana dengan menggunakan sengatnya, ia boleh memanjat benteng tersebut dengan mudah. Oleh itu kolam benteng yang didirikan perlulah memenuhi ciri dan syarat yang telah ditetapkan supaya ikan keli yang dipelihara tidak mudah untuk melarikan diri.

Menentukan lokasi penternakan
Lokasi penternakan yang tepat
Lokasi penternakan dikatakan tepat jika telah menepati aspek iaitu aspek social, ekonomi dan teknikal. Aspek sosial ini bermaksud menggunakan sumber yang terdapat di sekitar lokasi secara optimum. Sumber yang dimaksudkan bukan hanya dari sumber semulajadi tetapi juga sumber manusia iaitu tenaga kerja, peralatan dan bahan-bahan yang diperlukan.
Manakala aspek ekonomi pula, jarak lokasi kegiatan penternakan dengan tempat penjualan hasil adalah penting untuk dipertimbangkan. Ini juga bertujuan untuk menjamin kesegaran ikan tersebut apabila dijual kepada pengguna.
Aspek teknikal merupakan tenaga kerja yang pakar tentang ikan keli adalah diperlukan dari segi biologi, pembesaran, pencegahan haiwan pemangsa dan penyakit, penyediaan makanan dan pengumpulan.

Ternakan
Pada masa ini ternakan ikan keli dijalankan didalam sawah padi, kolam2 tanah, kolam kanvas dan tangki konkrit. Pada asasnya sistem pengeluaran ikan didalam sawah padi adalah berbentuk perangkap dimana ikan liar dari parit dan taliair atau telaga memasuki petak sawah yang ditenggelami air pada awal musim. Pengurusan petak sawah bagi menggalakan pertumbuhan plankton saperti pembajaan dan baja organik tidak dibuat. Ikan juaga tidak diberi makanan tambahan. Ikan2 yang biasa dituai ialah ikan keli kayu, Clarias batrachus, keli bunga, C.macrocephalus, ikan haruan Channa striatus dan ikan sepat, Trichogaster pectoralis. Antara halangan bagi ternakan ikan dalam sawah ialah tanaman padi dua musim yang menyebabkan tempoh tanaman yang singkat, kaedah mekanissasi intensif dan penggunaan racun perosak yang meluas.
Ternakan didalam kolam dijalankan secara semi-intensif, dimana kadar kemasukan adalah diantara 10 - 30 ekor/m2. Makanan rumusan atau perut ayam yang telah direbus serta bahan2 sampingan pertanian saperti hampas kacang soya/kelapa digunakan. Tempoh ternakan adalah 3 - 4 bulan, terutama bagi keli eksotika.
Ternakan ikan keli dalam tangki konkrit dan tangki fibreglass/kanvas semakin mendapat perhatian orang ramai, terutama bagi mereka yang tidak mempunyai kawasan yang besar. Saiz tangki konkrit digunakan berbeza2, biasanya tangki bersaiz 3m x 5m dengan kadar kemasukan lebih kurang 100/m2 digunakan.

Kuantiti dan kualiti air
Air merupakan faktor yang paling penting di dalam penternakan ikan. Kuantiti air adalah jumlah yang sedia ada dari sumbernya seperti sungai atau saluran untuk mengairi kolam. Air yang diperlukan bagi penternakan ikan keli tidak sebesar yang diperlukan bagi penternakan ikan-ikan lain seperti ikan emas. Ini disebabkan oleh alat pernafasan tambahan yang dimiliki ikan keli di mana ia boleh bernafas melalui udara bebas. Jumlah air yang diperlukan bagi penternakan ikan keli adalah 10 liter/minit.
Bagi pembenihan ikan keli, air yang paling sesuai digunakan adalah air dari telaga, sama ada telaga semulajadi mahupun telaga galian biasa.
Kualiti air adalah berbeza-beza dan mampu mempengaruhi kehidupan ikan keli. Kepelbagaian tersebut terdiri daripada sifat fizikal, kimia dan biologi air.
Sifat fizikal air meliputi suhu, kekeruhan dan warna air.
Sifat kimia air adalah kandungan oksigen(O2), karbon dioksida(CO2), pH (nilai keasidan), ammonia (NH3) dan alkali.
Sifat biologi air pula merangkumi jenis dan jumlah haiwan akuatik( mikroorganisma) seperti plankton, sebagai contohnya yang hidup di sesuatu kawasan perairan.
Suhu air mempengaruhi kelarutan oksigen dan nitrogen di dalam air pada tekanan 1 atm(atmosfera).
Kadar larutan oksigen dan nitrogen dengan air pada tekanan 1 atm.

Struktur tanah
Tanah merupakan faktor utama dalam pembuatan kolam penternakan. Tanah yang baik akan menghasilkan kolam yang kukuh terutamanya pada bahagian permatang dan sempadannya. Permatang yang kukuh dapat menahan tekanan air dan tidak mudah pecah. Kolam yang baik tidak cepat kering dan mempunyai daya penyerapan yang rendah.
Tanah yang sesuai dan baik untuk pembinaan kolam adalah tanah liat dan tanah berpasir dengan nisbah 3:2. Tanah dengan struktur seperti ini mudah dibentuk dan tidak mudah pecah.

Penternakan makanan semulajadi ikan keli
Kutu air atau Daphnia sp. Merupakan salah satu makanan bagi ikan keli. Ia boleh diperolehi secara semulajadi malahan ia juga boleh dikulturkan atau diternak. Tidak sukar untuk mendapatkan kutu air kerana ia berada dimana sahaja walaupun di dalam parit atau longkang.
Penternakan kutu air dilakukan di dalam kolam atau fiberglass yang berukuran 1m x 1m x 0.25m.
Kolam untuk penternakan kutu air, berukuran 1m x 1m x 0.25m. Bagi tujuan untuk mempercepatkan pertumbuhan kutu air dan harus dibaja dengan najis ayam.

Atau disesuaikan dengan keluasan tanah.
1. Mula-mula kolam dikeringkan dan dibersihkan kemudian ia disikan dengan air bersih.
2. Bagi mempercepatkan proses pertumbuhan kutu air, pembajaan harus dilakukan dengan menggunakan najis ayam yang telah kering sebanyak 2-5 gram/liter air.

Cara penternakannya adalah dengan ;
1. Menggunakan alat penapis supaya bahan-bahan yang kasar dapat diasingkan dan tidak masuk ke dalam kolam.
2. Perubahan pada warna air kolam kepada warna perang seperti air teh menandakan penternakan adalah baik.
3. Air tersebut dibiarkan selama 3-4 hari.
4. Pada hari kelima, bibit-bibit Daphinia akan terhasil. Ia akan tumbuh dengan cepat dan mencapai puncaknya pada hari ketujuh. Ketika itulah kutu air diambil untuk diberikan kepada benih ikan keli menggunakan jaring halus yang berukuran 1.5- 2 mm.
5. Penternakan kutu air di dalam kolam diulangi dengan dos ½ dari jumlah penternakan pertama bagi memastikan pertumbuhan kutu air yang berterusan. Proses ini dilakukan 7-8 hari sekali.

Pembenihan
Teknik pembenihan ikan keli tempatan tidak sama dengan ikan keli eksotika. Ikan keli tempatan di perairan umum membiak secara semulajadi dengan meletakkan telurnya di dalam sarang. Lubang-lubang permatang adalah sarang yang dibuat oleh ikan keli. Selain itu, ikan keli juga bersarang di bawah benda-benda yang tenggelam di dalam air seperti batu atau kayu.
Melalui konsep diatas para penternak mencuba mengusahakan penternakan ikan keli dengan menyediakan potongan-potongan buluh dan disimpan di dalam kolam.
Kaedah ini tidak berkesan. Ikan keli tidak bertelur pada potongan-potongan buluh yang disimpan di dasar kolam tetapi hanya pada bahagian berbentuk sarang atau kotak-kotak yang dipasang di tepi atau dipinggir permatang.
Teknik Pembenihan
Teknik pembenihan yang biasa dipraktik oleh para penternak adalah dengan 2 sistem iaitu sistem pembenihan secara berpasangan dan sistem pembenihan secara rawak.

Sistem pembenihan secara berpasangan
Induk yang dipilih adalah yang sudah cukup matang. Sepasang induk matang yang disenyawakan akan ditempatkan di dalam sebuah kolam yang kecil untuk proses persenyawaan.
Kolam yang digunakan adalah kolam tembok berukuran kira-kira 2m x 1m x 0.5m. Salah satu sudut kolam tersebut diletakkan sarang yang merupakan batu bata untuk ikan keli bertelur
Ukuran sarang adalah 30cm x 40cm x 20cm. Sebuah lubang atau pintu selebar 10cm disediakan pada bahagian hadapan sarang sebagai tempat keluar masuk ikan keli. Di dalam sarang tersebut diletakkan sabut di seluruh permukaan dasar sarang.

Sebelum proses persenyawaan dilakukan, kolam akan dikeringkan dan dibersihkan unutk membunuh kuman-kuman penyakit. Seterusnya kolam diisikan dengan air bersih dan jernih pada kedalaman 15-20 cm. Induk yang ingin disenyawakan dipilih daripada sepasang ikan keli matang (jantan dan betina) di mana berat masing-masing adalah sama atau hampir sama. Induk dimasukkan pada waktu pagi di mana persenyawaan biasa berlaku pada waktu malam. Ini telah terbukti di mana pada pagi keesokan harinya terdapat telur-telur yang terhasil dan terlekat pada sabut sarang. Telur-telur tersebut akan dijaga oleh kedua-dua induknya secara bergilir-gilir.

Telur yang terhasil akan menetas selepas tiga hari. Pada hari keempat, benih yang baru menetas akan diberi makanan tambahan yang merupakan kutu air atau cacing sutera. Induk jantan dan betina akan ditangkap dan dipindahkan kekolam pemeliharaan induk, setelah benih berusia 7 hari. Benih akan dipelihara selama 3 minggu di kolam persenyawaan kemudian akan dipindahkan ke tempat pemeliharaan.

Sistem Pembenihan secara rawak
Bagi sistem ini, kolam pemeliharaan induk berfungsi sebagai kolam persenyawaan. Dipinggir kolam diletakkan kotak-kotak sebagai tempat persenyawaan. Kotak tersebut dibuat daripada tembok atau bancuhan simen dengan ukuran 50cm x 50cm x 60cm. Sebuah lubang sebesar 15cm disediakan pada bahagian dalam kotak tersebut sebagai tempat perlindungan keluar masuk ikan keli. Pada dinding bahagian belakang dibuat lubang untuk mengeringkan atau menangkap benih yang terhasil. Di dalam kotak tersebut dilapisi dengan sabut supaya benih akan terlekat padanya. Pada bahagian atas kotak mestilah ditutup agar keadaan gelap kerana ikan keli lebih gemar bertelur dalam keadaan gelap. Jarak antara kotak persenyawaan adalah 100cm.

Sepasang ikan keli akan diletakkan di dalam kolam seluas kira-kira 4m2. Penebaran induk dilakukan pada waktu pagi dan petang. Induk yang ingin disenyawakan haruslah dibekalkan dengan makanan berkhasiat seperti pellet atau makanana tambahan yang lain. Induk ikan keli yang sudah matang akan mencari sendiri pasanganya. Jika ikan keli telah menemui pasangannya, induk akan mencari kotak atau sarang yang dikehendaki. Kemuadian induk akan menjalani proses persenyawaan di dalam kotak di mana induk betina akan melepaskan telur manakala induk jantan akan mengeluarkan spermanya. Telur-telur yang hasil persenyawaan akan melekat pada sabut yang diletakkan di dalam sarang.

Telur akan menetas setelah tiga hari disenyawakan dan pada hari keempat ia akan diberi makanan yang terdiri daripada kutu air atau cacing sutera. Setelah seminggu, benih ikan keli bolehlah dipindahkan menggunakan jaring halus untuk dipelihara di tempat lain.

Pembenihan secara akuakultur
Kaedah pembenihan secara kultur, benih ikan keli yang dihasilkan akan bertahan lebih lama dan risiko kematian adalah kurang jika dibandingkan dengan kaedah tradisional atau semi-intensif. Kegiatan pembenihan secara intensif meliputi penyediaan calon induk, pemilihan induk yang matang dan penyediaan kolam yang digunakanuntuk persenyawaan. Bagi mendapatkan hasil yang maksima, setiap kegiatan haruslah dijalankan mengikut prosedur yang telah ditetapkan.

Induk
Penyediaan induk yang baik bergantung kepada pengetahuan tentang ciri-ciri yang terdapat pada setiap induk jantan dan betina. Induk yang baik memiliki ciri-ciri seperti berikut;
1. Induk betina
- Kepala lebih kecil, mulut membulat, perut lebar, berbentuk tubuh yang mantap
dan tidak cacat .
- Beratnya mencapai 150-250 gram apabila berumur melebihi satu tahun.
- Induk bukan dari jenis yang sama.
- Induk memiliki tindak balas terhadap makanan, tahan kepada penyakit dan cepat sembuh.
2. Induk jantan
- Bentuk tubuh yang mantap, mulut membulat, berwarna cerah dan tidak
cacat.
- Pada umur minima satu tahun boleh mencapai berat diantara 150-250gram.
- Induk bukan dari jenis yang sama.
- Induk memiliki tidak balas terhadap makanan, tahan kepada penyakit dan cepat sembuh.

Terdapat beberapa perkara yang perlu dipertimbangkan sebelum memelihara induk ikan keli. Diantaranya adalah;
1. Kepadatan penebaran.
2. Jenis dan jumlah makanan yang diberikan.
3. Kolam yang digunakan biasanya merupakan kolam yang menjadikan tanah sebagai dasarnya berukuran 20m x 10m 1m.
4. Kolam mestilah dikeringkan dan diairi semula.
5. Menternak kutu air. Kolam perlu dibaja dengan menggunakan najis ayam sebanyak 200gram/m2 seterusnya diletakkan kapur pertanian sebanyak 50gram/m2 . Kapur ini bertujuan untuk membunuh kuman-kuman penyebab penyakit yang terdapat di dalam kolam tersebut.
6. Kolam disikan dengan air setinggi 60-80cm dari dasar kolam. Sebanyak 10-15 ekor/ m2 induk ikan keli dimasukkan ke dalam kolam di mana berat induk adalah diantara 50-100gram seekor. Semasa proses pemeliharaan, induk diberi makanan tambahan seperti palet dengan kadar;
1. Protein ..............32-35%
2. Lemak ...............7-8%
3. Karbohidrat.......30%
4. Vitamin..............1-2%
Jumlah makanan yang diberikan sehari adalah 3% daripada berat ikan tersebut dengan kekerapan 3 kali sehari;
1. Pagi
2. Petang
3. Malam
Pemeliharaan dilakukan selama 2-3 bulan. Pada masa ia boleh dipindahkan, berat ikan keli boleh mencapai 150gram seekor.

Pemeliharaan Induk
Induk jantan dan betina dipelihara secara berasingan di dalam kolam yang mempunyai batas. Luas kolam pemeliharaan adalah sekitar 40-50 m2 . Kolam yang hendak digunakan perlulah dikeringkan selama 3-4 hari unutk membunuh kuman-kuman penyakit dan memudahkan pembajaan. Kolam akan dibaja dengan 200 gram/ m2 .najis ayam dan kapur sebanyak 50 gram/ m2 . Kolam disi dengan baja dengan air pada kedalaman 80-100cm. Sebanyak 3-5 ekor/m2 induk ikan keli sahaja akan dimasukkan ke dalam kolam.
Untuk mempercepatkan proses kematangan, makanan tambahan iaitu makanan buatan dan makanan alternatif. Makanan buatan merupakan pellet. Makanan tambahan alternatif yang boleh diberikan adalah anak-anak ikan atau daging siput. Makanan tambahan ini diberkan secara berselang-seli dengan makanan palet.
Indeks Kematangan Gonad Ikan keli betina( Sember rujukan : www.dof.gov.my)

Penentuan tahap kematangan gonad ini adalah berdasarkan pada perkembangan gonad, perubahan warna telur dan pengisian pada rongga perut. Penerangan bagi tahap kematangan gonad 1 hingga 4 adalah seperti berikut ;
1. TKG 1 (belum matang)
Gonad kecil dan memanjang 10-15mm, lutsinar dan butir-butir telur belum terbentuk. Jika sudah terbentuk, telur tersebut masih berwarna lutsinar
2. TKG 2 (mulai matang)
Gonad semakin membesar dan berwarna kuning. Butir-butir telur sudah mula
kelihatan dan panjangnya diantara 15-20mm.
3. TKG 3 ( matang)
Gonad lebih besar, panjang 20-30 mm, berwarna kuning keperangan. Butir-butir telur memenuhi setengah daripada ruang perut dan mula memberi tekanan terhadap alat pencernaan ke bahagian dorsal(punggung)
4. TKG 4(sangat matang)
Gonad besar dengan panjang 30-50mm, berwarna kuning keperangan dan memenuhi dua pertiga ruang perut.

Indeks Kematangan Gonad Ikan keli jantan
1. TKG 1 (belum matang)
Gonad kecil dan panjang 5-12mm, berwarna putih dan permukaan gonad mula tidak rata.
2. TKG 2 (mulai matang)
Gonad lebih besar, panjang 12-30mm, berubah kepada warna putih jernih dan mula kelihatan bentuk gerigi mula kelihatan.
3. TKG 3 ( matang)
Gonad besar dengan panjang 20-45mm dan mula memenuhi 2/3 ruang perut. Warna
jernih dan kelihatan bergerigi pada gonad semakin membesar.
4. TKG 4(matang)
Gonad bear dan panjang, memenuhi 2/3 ruang perut. Gonad mula mengembung dan berwarna jernih.

Teknik pensenyawaan
1) Teknik pensenyawaan berpasangan di dalam kolam
i. Kolam yang digunakan seluas 1-2m2 dan sudah dikeringkan dan dibersihkan.
ii. Pintu pembuangan perlu ditutup dengan sempurna.
iii. Kolam diisikan dengan air pada kedalaman 40cm.
iv. Sabut disediakan sebagai tempat untuk benih melekat.
v. Pemilihan ikan keli yang telah matang gonad dari kolam pemeliharan induk.
vi. Waktu pensenyawaan pada waktu pagi.
vii. Pengawasan perlu dilakukan pada setiap hari bagi memastikan pensenyawaan telah berlaku atau belum.
viii. Sabut di dalam sarang tersebut perlu dipantau bagi memastikan samaada induk sudah bertelur atau belum.
ix. Tanda-tanda mengawan, terdapat telur berwarna kuning jernih pada sabut.
x. Setelah beberapa hari induk akan tetap menjaga sarangnya. Dilihat juga ikan keli yang melibaskan ekornya bagi mengekalkan kesegaran atau untuk meningkatkan kandungan oksigen di dalam air.
xi. Benih akan diberi makanan tambahan iaitu kutu air atau cacing sutera setelah masuk hari keempat.
xii. Tempoh penjagaan di kolam pensenyawaan adalah lebih kurang 2-3 minggu seterusnya benih akan dipindahkan ke tempat pemeliharaan.
2) Teknik pensenyawaan secara rawak
i. Luas kolam yang dicadangkan 15-20 m2.
ii. Kolam perlu dilengkapi dua pintu air untuk kemasukan air dan pengeluaran air.
iii. Pada pintu-pintu tersebut dipasang jaring untk mengelakkan ikan terkeluar.
iv. Sarang dibina disisi-sisi kolam sebanyak 1/3 dari jumlah induk betina. Ukuran sarang adalah 50cm x 50cm x 60cm diperbuat daripada simen.
v. Kedalaman yang diperlukan adalah 30cm. Satu lubang juga dibuat pada dinding bahagian dalam sarang untuk laluan keluar masuk ikan tersebut.
vi. Jarak antara sarang adalah 75-100cm. Selain itu, bahagian atas sarang tersebut perlulah gelap. Kolam yang hendak digunakan perlulah dikeringkan selama 3-4 hari untuk membunuh kuman-kuman penyakit dan memudahkan pembajaan. Kolam akan dibaja dengan 200 gram/ m2 najis ayam dan kapur sebanyak 50 gram/ m2 . Kolam disi dengan baja dengan air pada kedalaman 80-100cm. Sebanyak 3-5 ekor/m2 induk ikan keli sahaja akan dimasukkan ke dalam kolam.
vii. Nisbah 1jantan dan 2 betina. Induk-induk ini mestilah matang.
viii. Cara yang sesuai untuk meransang proses pensenyawaan adalah mengawal ketinggian air kolam mengikut keadaan yang sepatutnya.
ix. Telur akan menetas setelah 2-3 hari pensenyawaan berlaku.

Pemeliharaan
1. Penyediaan
1. Memudahkan pengendalian, pemeliharaan sebaik-baiknya di dalam kolam tembok. Disamping itu, kolam tersebut harus terlindung daripada cahaya matahari. Kolam perlu dilengkapi dengan pelindung tetap seperti atap genting atau plastik atau pelindung sementara seperti atap atau daun kelapa.
2. Pelindung juga melindungi kolam daripada dimasuki oleh air hujan kerana dikuatiri benih ikan akan mati akibat perubahan suhu secara mendadak.
3. Ukuran kolam pemeliharaan 5-10 m2 dan dilengkapi dengan pintu masuk dan keluar air. Kolam perlu dikeringkan 1-2 hari dan dibersihkan dari sebarang kotoran. Ketinggian air kolam tersebut adalah sekitar 20-30cm.
4. Tanaman air atau potongan – potongan buluh juga diletakkan di dalam kolam kerana ikan keli amat gemar kepada kawasan yang gelap sebagai tempat berlindung.

2. Penebaran
1. Penebaran benih lebih sesuai dilakukan pada waktu pagi atau pada suhu yang masih rendah untuk mengelakkan tekanan pada benih tersebut.
2. Benih adalah berasal dari hasil proses pensenyawaan.
3. Jika benih dari tempat lain, ia perlu dibiasakan dahulu dengan keadaan yang baru sebelum dilepaskan ke dalam kolam. Caranya adalah membiarkan alat pemindah benih terapung-apung selama 5 minit di atas permukaan air kolam pemeliharaan. Kemudian air ditambahkan sedikit demi sedikit sehingga keadaannya sama dengan permukaan air di kolam pemeliharaan. Benih dibiarkan keluar dengan sendiri ke dalam kolam pemeliharaan.
4. Kepadatan penebaran adalah 150 ekor/ m3 air.

3. Teknik-teknik pemeliharaan
1. Benih akan diberi makanan tambahan yang merupakan makanan buatan berkadar protein 40% sepanjang tempoh pemeliharaan
2. Jumlah makanan yang diberi adalah 5% dari berat benih ikan keli yang dipelihara.
3. Makanan diberikan dengan cara menaburkannya keseluruhan permukaan kolam dan dilakukan 3 kali sehari pada waktu pagi, petang dan malam.
4. Kualiti air sentiasa dijaga. Jika air tidak mengalir, penggantian air perlu dilakukan dengan menggunakan tiub sifon. Kaedah ini dapat menyingkirkan kotoran yang terdapat di dalam kolam.
5. Jika pengairan air 0.04 liter/saat, tiub sifon tidak perlu digunakan.
6. Jika terdapat ikan yang diserang penyakit atau mati, benih tersebut perlu diasingkan atau dibuang dengan segera supaya penyakit tersebut tidak tersebar lalu menjangkiti ikan lain
7. Ikan keli akan dipelihara di dalam kolam pemeliharaan selama 2 bulan atau bergantung kepada keperluannya.

4. Pengumpulan
1. Setelah benih mencapai ukuran tertentu atau sudah menepati syarat, maka ia boleh dikumpul.
2. Pengumpulan dijalankan pada waktu pagi atau petang di mana suhu adalah rendah.
3. Cara pengumpulan adalah dengan mengeringkan kolam secara perlahan-lahan sehingga air tinggal disaluran tengah.
4. Benih tersebut ditangkap secara berhati-hati dengan menggunakan alat penangkap yang halus.
5. Ini bertujuan untuk mengelakkan benih daripada luka atau cacat semasa penangkapan.
6. Benih ditampung dengan alat yang sesuai atau kolam lain untuk dipelihara ditempat pembesaran atau untuk dijual.
7. Jika teknik pemeliharaannya sesuai dan benih tidak dijangkiti penyakit, tempoh pemeliharaan adalah sekitar 20%-30% dari jumlah benih dilepaskan.

Pembesaran
1. Ikan keli dijual, biasanya mempunyai berat 150-200 gram seekor atau sewaktu ikan keli berumur 6 bulan jika ia diberi makanan tambahan yang mencukupi, kualiti air yang baik dan tiada serangan penyakit dan haiwan pemangsa.
2. Ikan keli adalah lebih sesuai jika diternak di dalam kolam yang bertembok dengan dasarnya adalah tanah dan lumpur. Ini merupakan sifat semulajadi ikan keli yang suka membuat lubang pada batas dan menyukarkan untuk melihat. Tetapi keluasan kolam yang dibina haruslah tidak terlalu besar kerana dikuatiri akan menyukarkan proses penangkapan ikan keli. Luas kolam yang disyorkan adalah 20 m2.
3. Jika kaedah kanvas atau ternakan di dalam kolam pastikan ciri-ciri tempat tinggal yang sama perlu digunakan seperti kolam tanah.

Pemindahan
Pemindahan adalah proses memindahkan ikan keli dari satu tempat ke satu tempat yang lain. Pemindahan dilakukan mengikut saiz ikan keli, samada yang masih kecil iaitu benihnya sehinggalah yang berukuran besar. Sistem pemindahan ini boleh dijalankan dengan dua cara iaitu cara terbuka dan cara tertutup.
Pemindahan secara terbuka.
Kaedah ini sesuai untuk ikan keli yang berukuran besar dan sudah boleh dipasarkan. Alat yang digunakan adalah tong plastik atau kolam yang diperbuat daripada fibre glass.

Pemindahan secara tertutup
Alat yang digunakan untuk pemindahan secara tertutup ini adalah dengan menggunakan karung plastik yang mengandungi oksigen.
Faktor- faktor lain semasa proses pemindahan.
1. Teknik pemindahan
2. Alat pengangkutan
3. Tempoh dan jarak pemindahan
4. Jumlah atau ukuran ikan keli
5. Waktu pemindahan dijalankan.

Ukuran benih
Alat-alat yang diperlukan adalah tabung oksigen, getah sebagai pengikat dan baldi untuk mengisi air. Air yang digunakan perlu diendapkan selama satu hari untuk membebaskan gas-gas beracun.
Jika pemindahan secara terbuka, alat yang perlu disediakan adalah air bersih dan tong plastik dengan kapasiti 20-200 liter di mana ia bergantung kepada jumlah benih yang akan dipindahkan.
Semasa diangkut, benih tidak akan diberi makan atau dipuasakan selama beberapa jamsupaya tidak mengeluarkan kotoran semasa pemindahan. Ini bertujuan untuk mengelakkan keracunan atau kekurangan oksigen sewaktu pemindahan akibat dari kekotoran.
Ikan keli yang dipindahkan mestilah sihat, tidak cacat atau tiada sebarang luka.

Ukuran besar (jualan)
Pemindahan bagi ikan keli yang bersaiz besar iaitu 50 gram keatas bagi seekor lebih sesuai menggunakan kaedah terbuka. Disamping itu sistem terbuka, membolehkan ikan keli bernafas melalui udara bebas. Saiz tong plastik perlu disesuaikan dengan jumlah ikan keli yang akan dipindahkan serta kemudahan pengangkutan yang ada. Tong untuk memindahkan ikan keli ada dipasaran dengan kapasiti 20 liter - 200 liter.

Pencegahan haiwan pemangsa dan penyakit
1. Masalah yang sering dihadapi oleh penternak ikan adalah serangan haiwan pemangsa dan penyakit.
2. Pencegahan adalah langkah utama yang perlu dilakukan sebelum serangan haiwan pemangsa dan penyakit.

Haiwan pemangsa
Haiwan pemangsa yang biasa menyerang ikan keli datang dari udara, darat dan air. Langkah pencegahan serangan haiwan ini adalah ;
1. Kolam perlu dikeringkan dan dikapurkan sebelum digunakan. Penggunaan kapur mesti mengikut dos yang telah ditetapkan.
2. Jaring perlu dipasang pada pintu kemasukan air bagi menghalang kemasukan haiwan pemangsa ini.
3. Haiwan pemangsa yang sering menyerang ikan keli adalah ular, belut dan ikan gabus.

Kerosakan/Penyakit
Terdapat dua jenis penyakit yang menyerang ikan kelii iaitu penyakit yang menyerang bahagian dalaman tubuh seperti jantung, hati atau usus dikenali dengan istilah endotern. Kedua, penyakit yang menyerang bahagian luar tubuh ikan keli seperti sirip, dikenali dengan eksotern.
Langkah-langkah pencegahan penyakit yang dilakukan seperti berikut ;
1. Sebelum pemeliharaan, kolam perlu dikeringkan dan dikapurkan untuk membunuh kuman pembawa penyakit.
2. Kualiti air mesti sentiasa dijaga.
3. Makanan tambahan yang diberikan haruslah sesuai dengan dos yang telah ditetapkan dimana jika berlebihan akan mengganggu kualiti air.
4. Proses pengumpulan dan pengambilan mesti dilakukan dengan baik dan berhati-hati agar ikan tidak mengalami kecederaan.
5. Binatang-binatang pembawa penyakit seperti burung atau siput haruslah dihalang daripada memasuki kolam penternakan.
Didalam air, patogen(agen penyebab penyakit)mudah merebak antara ikan melalui insang dan kulit. Secara amnya, ikan yang diternak pada keadaan yang optimum akan menghalang tekanan patogen dalam air saperti bakteria, virus dan kulat. Kualiti air yang buruk, pemakanan yang kurang, pengedalian ikan secara kasar dan sekitaran yang tidak selesa boleh menggangu ikan2 ini. Ini boleh menyebabkan daya tahan badan menjadi kurang dan terdedah kepada serangan penyakit. Keadaan ini boleh serius bagi anak ikan kerana mereka masih dalam proces untuk menbina daya tahan penyakit.
Ikan keli yang mula diserang penyakit boleh dikesan dengan mata kasar melalui tanda2 seperti :
a) Warna kulit akan menjadi lebih hitam daripada biasa, warna ditepi2 sirip pula menjadi kemerahan.
b) Ikan tudak mempunyai selera makan.
c) Ikan tidak aktif dan timbul kerpemukaan dengan keadaan menegak kepada permukaan air.
d) Berenang tidak tentu arah, kadangkala berenang secara berputar.
e) Kulat didapati dimisai dan badan. Kadang2 sirip dan misai kudung.
f) Bahagian pinggangnya bengkak.
g) Luka2 dibadan dan bengkak perut.
h) Sirip reput dan rapoh.
i) Bintik2 merah diseluruh badan.

Mikrobial(Bakteria dan Virus
Keosakan yang biasa pada ikan2 keli ialah disebabkan oleh patogen dan pasit/perosak. Bakteria Aeromonas hydrophila, bakteria saprofitik yang terdapat didalam air terjadi apabila jangkitan sekunder oleh tekanan kerana kadar kepadatan yang tinggi dan makanan ikan baja yang digunakan yang menyebabkan kualiti air yang buruk. Ia boleh menyebabkan 90% kematian dikolam asuhan dan 50% didalam kolam tumbesaran.
Ikan yang berpenyakit menunjukkan tanda2 kurang selera makan, lesu, berenang perlahan2 dan kelihatan mencungap dipermukaan air bagi mendapat udara dan berada dalam keadaan tegak pada permukaan air. Kematian berlaku dalam tempoh yang singkat. Kulit ikan yang perpenyakit berwarna pudar dengan tompok merah halus disekililing perut. Bahagian abdomen kelihatan membesar dengan sirip kaudal dan reput. Rongga badan berisi dengan bendalir, buah pinggang membengkak dan hati berwarna pucat. Keadaan ini dinamakan haemorrhagic septicaemia iaitu kedapatan racun dan bakteria dalam darah. Ini bersama2 dengan Pseudomonos spp. menjadi punca utama haemorrhagic septicaemia ini. Kaedah pengawalan paling baik ialah dengan mengurangkan kedapatan ikan.

Bakteria Myxobacteria sp
Ia merupakan jangkitan sekunder, menyerang ulser yang disebabkan oleh lain2 patogen diatas permukaan air. Biasanya ia menyerang bahagian dorsal badan, kelihatan bintik putih yang meliputi ulser dan merebak kebahagian lain badan. Ikan yang dijankiti dalam keaadan tegak dengan permukaan air atau tingkah laku berenang secara mengereng. Kawalan dengan antibiotik seperti Kloramfenikol, Terramaisin atau Oksitetrasiklina sebanyak 5 - 7.5mg bahan aktif/kg makanan ikan sehari selama 5 - 15 hari.

Kulat Saprolegnia sp
Kulit ikan yang diserang oleh kulat ini kelihatan seperti diselaputi oleh bentuk2 kapas. Serangan penyakit terjadi akibat dari kecederaan pada kulit yang disebabkan oleh pengendalian, pemukatan dan serangan ektoparasit. Jangkitan yang teruk boleh menyebabkan kematian. Penyakit ini njuga menjangkiti telur dan rega. Kawalan anak ikan dan ikan besar dengan malakit hijau sebanyak 0.05 - 1.0ppm selama 24jam.

Perasit Protozoa
Parasit2 protozoa yang didapati didalam ternakan keli ialah :
a) Trichodina spp, protozoa halus yang berbentuk piring yang terdapat disekeliling insang dan permukaan luar badan dan sirip. Biasanya ia merbahaya kepada rega dan anak2 ikan.
b) Oodinium sp, Ichthyobodo(Costia)sp, Henneguya sp, Myxosoma/Myxobolus Sistanya didapati didalam organ biak ikan dan Myxidium sp didalam pundi halus dan usus.
Kaedah kawalan ialah dengan formalin dengan kadar 25 - 50ppm atau Dipterex dengan kadar 0.25ppm pada kolam.

Parasit Cacing
Gyrodactylus spp, parasit monogenea didapati dikulit2 dan dijumpai didalam bilangan yang ketara. Ia boleh menyebabkan kematian yang banyak terutama kematian yang tiba2 bagi ikan yang sihat. Ikan yang dijangkiti akan mempunyai tompok2 hitam pada badan dengan kulit yang mengelupas. Dicadangkan kawalan Dipterex dengan kadar 0.25ppm atau formalin dengan kadar 50ppm disyorkan.

Kerosakan oleh lain-lain punca
Penyakit yang bukan berpunca daripada mikrob iaitu penyakit kekurangan zat makanan atau mutu air yang teruk boleh menyebabkan kesihatan ikan tergugat, tulang kepala retak, badan bengkok/cacat, otak bahagian belakang musnah dan bengkak perut. Ikan keli kayu dan bunga adalah sangat mudah dijangkiti epizootic ulcerative syndrome(EUS). Ikan yang dijangkiti akan menunjukkan lika pada kulit dan otot serta mata yang terbonjol. Musuh2 lain ialah burung, biawak, ular, katak, ketam, ikan haruan, belut, ikan puyu dan lain-lain.

Amalan sebelum ikan distok
Sebelum ikan dimasukkan kedalam kolam untuk ternakan, perkara-perkara berikut hendaklah diamalkan:
a) Bungkusan plastik yang mengandungi benih hendaklah diremdam terlebih dahulu didalam kolam yang akan dilepaskan benih selama kira2 10minit supaya suhu air dalam bungkusan sama dengan suhu air kolam.
b) Bungkusan plastik dibuka dan air kolam dimasukkan sedikit demi sedikit kedalamnya sebelum benih dilepaskan.
c) Lepas ikan kedalam kolam tersebut.
d) Selepas 6 jam, makanan halus dan lembut boleh diberikan sedikit demi sedikit. Anak ikan boleh juga diberikan rawatan secara rendaman sebelum dimasukkan kedalam kolam dengan kaedah seperti berikut:
Formalin
Ikan dirawat dengan 25ppm formalin untuk tempoh masa yang tidak tetap(2.5ml formalin dicampur dengan 100 liter air)
Furanace atau Garam Biasa
Sebagai langkah kawalan, semasa memindahkan ikan dan sebelum memasukkan ikan disyorkan ubat Furanace(Nifurpirinol, iaitu satu derivatif nitrofuran)dibubuh dalam air dengan kadar 10mg/liter air atau larutan 5.0g garam biasa bagi setiap liter air. Rawatan ini dijalankan secara rendaman selama 1 - 3 jam.
Dipterex
Rendaman dalam 0.25ppm Dipterex selama 3 jam.

Menggunakan bahan kimia didalam air
a) Formalin, 20 - 100ppm : selama 1 jam(guna apabila suhu tinggi).
b) Dipterex, 0.25 - 0.30ppm : selama 12 jam(rawatan pada suhu tinggi dan pancaran matahari).
c) Kalium permanganat, 2 - 4.0ppm : selama 1 jam(rawatan semasa naungan)
d) Garam biasa, 1 - 3% : selama 20minit. Garam dan beberapa asid hendaklah digunakan dengan berhati2. Lendir pada badan ikan melekat pada organ pembantu pernafasan. Ia akan menghasilkan sebatian yang membahayakan ikan.

Menggunakan bahan kimia didalam air atau makanan dilakukan dengan:
1) Melarutkan 1mg antibiotik kedalam 1 - 2 liter air atau,
2) Mencampurkan 5.0 - 7.5mg antibiotik kedalam 1kg makanan. Antibiotik adalah bahan yang didapati daripada mikro-organisma seperti kulat dan bakteria dimana ia berupaya menahan pembiakan mikro-organisma serta membunuhnya. Bagi ternakan keli, Oksitetrasiklina adalah disyorkan. Walaupun begitu adalah dinasihatkan supaya penggunaan antibiotik tidak diamalkan kerana kemungkinan kesan sampingan kepada ikan yang kita makan dan persikitaran perairan dimana kesan dari kedua2 ini mungkin menyebabkan terdapat bakteria-bakteria yang lebih rintang terhadap penyakit.

Pemakanan
Biasanya ikan-ikan didalam kurungan mengalami penyakit kekurangan zat makanan. Ini akan mengurangkan daya tahan ikan terhadap penyakit. Oleh itu, pemberian makanan yang seimbang adalah penting bagi memastikan pertumbuhan ikan yang baik.

Jenis-jenis Makanan
1) Perut Ayam : makanan ini tidak begitu digalakkan kerana ia boleh menyebabkan ikan yang diternak mengandungi banyak lemak, bau yang tidak menyenangkan dan pencemaran kolam. Jika tidak ada pilihan lain, ia boleh digunakan dengan mengurangkan kesa2 yang tidak dikehendaki itu. Caranya ialah perut hendaklah direbus dan dicincang dengan mesin pengisar sebelum diberi makan kepada ikan.
2) Campuran Ikan Baja/Dedak Padi : makanan campuran ikan baja (10%) dengan dedak padi (90%) boleh diberikan dari peringkat permulaan ternakan kesaiz pasaran. Cara lain ialah dengan menggunakan ikan baja dan 10% dedak padi sehingga jualan. Campuran makanan ini boleh diberi untuk selama dua bulan pertama, selepas itu, kadar dedak padi dinaikkan sehingga 20% dan satu bahagian beras hancur masak. Pada bulan keempat, kadar beras hancur masak ditingkatkan kepada dua bahagian.
Makanan diatas hendaklah dijadikan bentuk"paste"(belacan) dengan menggunakan mesin pengisar. Makanan diberikan sedikit demi sedikit sebanyak dua kali sehari sehingga ikan tidak lagi memakannya. Ini bagi mengelakkan pembaziran dan kemerosotan mutu air. Campuran vitamin dan garam galian adalah bagi menghasilkan campuran makanan yang bermutu.
3) Makanan Rumusan : Makanan rumusan yang mengandungi 25 - 30% protein mentah dan dihasilkan dari baha-bahan tumbuhan dan haiwan serta vitamin dan garam galian adalah disyorkan. Kelebihan penggunaan jenis makanan ini ialah ia lebih seimbang, bersih, mudah didapati dan disimpan dan kadar penukaran makanan yang cekap.

Salah satu formula untuk membuat makanan rumusan bagi ikan keli adalah seperti berikut;

Hampas ikan : 21-25%,
Hampas kacang soya : 28-34%,
Beras hancur masak : 35-44%,
Lemak haiwan : 4-5%,
Dikalsium fostat : 1.0%,
Garam : 0.75%,
Premix Garam Galian @ : 0.1%,
Premix Vitamin @@ : 0.1%,
Antibiotik @@@ : 0.05%,

# @ termasuk CaCO3, MnSO4.7H2O, ZnSO4.7H2o, CuSO4.5H2O dan FeSO4.7H2o.
Kadar bagi diet ikan diperairan panas.
#@@ mengandungi vitamin A, C dan D3 dengan jumlah yang dicadangkan bagi diet diperairan panas.
#@@@ oksitetrasiklina atau lain-lain yang dibenarkan.

Makanan yang dicadangkan hendaklah mempunyai kandungan protein mentah minimum 25-30%, minimum lemak 3%, maximum gentian 8%, maksimum abu 16%, maksimum kelembapan 12% dan minimum fosforus 1%.
Makanan diberi pada pukul 7.30pagi dan 5.00petang. Makanan diberi dengan tangan secara sedikit demi sedikit hingga ikan berhenti memakan. Kadar pemberian makanan ialah 3-12% berat badan ikan/sehari bergantung kepada tahap penerimaannya dan peringkat tumbesaran.
Kadar diatas adalah sebagai panduan. Kadar yang sebenar bergantung kepada suhu, kandungan oksigen dan kandungan ammonia didalam air serta kesihatan ikan.
Dalam keadaan biasa, adalah sukar untuk menilai keberkesanan pemakanan keli kerana kebanyakan makanan akan tenggelam kedasar. Oleh itu adalah dicadangkan makanan rumusan jenis terapung diberi kepada ikan ternakan. Ini akan memudahkan kerja mengangar jumlah makanan yang telah dimakan. Walaupun begitu, harganya adalah tinggi. Dasar kolam dikawasan pemberian makanan perlu diperiksa untuk menilai baki2 makanan yang tinggal selepas setengah jam makanan diberi. Jika ada sisa makanan, kuantiti makanan perlu dikurangkan supaya pencemaran air dapat dikurangkan disamping menjimatkan kos.

Jenis-jenis makanan tambahan
1. Terdapat dua jenis makanan yang digemari oleh ikan keli iaitu makanan semulajadi dan makanan buatan. Makanan semulajadi terdiri daripada mikro organisma hidup di dalam air seperti plankton dan makanan buatan pula adalah makanan palet buatan.
2. Alternatif lain untuk makanan ikan keli ialah anak-anak ikan dari hasil tangkapan yang tidak boleh dipasarkan, sisa buangan penternakan ayam dan ikan serta daging siput.
3. Makanan buatan seperti palet biasanya mengandungi daging dari serbuk ikan dengan kandungan protein melebihi 30%.
4. Makanan buatan dalam bentuk palet akan diberikan pada ikan keli yang sudah agak besar iaitu mencapai berat melebihi 30 gram. Palet yang besar akan dihancurkan dan diberikan kepada ikan keli yang masih kecil.

Makanan tambahan boleh diberikan kepada benih-benih ikan semasa peringkat asuhan. Jenis2 makanan tambahan yang boleh diberi ialah; Makanan rumusan dan Hampas ikan(fish meal).
Jenis makanan yang diberikan bergantung kepada faktor sama ada ia mudah didapati, mudah disediakan serta kos yang berpatutan. Walaupun begitu, makanan rumusan yang mengandungi 60% protein mentah dicadang diberikan kepada anak ikan diperingkat ini. Makanan ini diberi sehingga ikan berhenti makan. Makanan tambahan yang diperbuat daripada telur, kadar 2 biji kuning bagi 1000 ekor anak ikan pada hari pertama dan kedua adalah dicadangkan. Ia dihancurkan dan ditabur disekililing permukaan kolam. Kadar bagi makanan ikan baja yang telah dihancurkan ialah 3kg/100,000 anak ikan. Kadar ini ditinggatkan sebanyak 0.5kg bagi setiap 2-3 hari pemiliharaan. Makanan diberi sebanyak dua kali sehari iaitu pada awal pagi dan petang.

Makanan buatan
1. Makanan buatan yang dikeluarkan oleh kilang lebih mudah untuk diperoleh terutamanya di kedai-kedai yang ada menjual makanan ikan. Harganya bergantung kepada kandungan proteinnya.

Buatan kilang
Makanan yang dihasilkan oleh kilang adalah dalam bentuk palet dengan pelbagai saiz. Protein yang terkandung di dalam palet adalah berbeza-beza bergantung kepada kilang yang menghasilkannya dan jenis ikan yang digunakan. Terdapat dua jenis palet iaitu palet terapung dan palet tenggelam.
Palet terapung merupakan palet yang akan terapung diatas air jika ditaburkan ke dalam kolam manakala palet tenggelam akan jatuh ke dalam kolam.

Buatan sendiri
Peralatan yang digunakan untuk membuat palet boleh diperolehi di kedai-kedai. Selain itu bahan-bahan utama yang diperlukan ialah ;
1. Protein – Serbuk ikan, daging siput atau sisa dari penternakan.
2. Karbohidrat – Dedak halus, hampas soya
3. Mineral – Boleh diperolehi dari kedai-kedai menjual makanan ternakan.
4. Vitamin - Boleh diperolehi dari kedai-kedai menjual makanan ternakan.
Cacing juga boleh diberikan kepada ikan keli yang berusia empat hari.

Makanan alternatif
1. Sisa-sisa ternakan ikan, ayam dan daging.
2. Harga yang lebih murah dan mempunyai kandungan protein yang tinggi.

Sisa penternakan
1. Sumber-sumber ayam telah mati tetapi tidak lagi membusuk , boleh digunakan untuk dijadikan makanan ikan keli ini.
2. Ayam-ayam ini adalah lebih baik direbus dahulu sebelum diberikan kepada ikan keli ini.
3. Pemberian ayam kepada ikan-ikan perlu mengikut sukatan tertentu untuk mengelakkan kualiti air di dalam kolam terjejas.

Sisa perusahaan ikan kering
Sisa buangan perusahaan ikan kering sebagai makanan alternatif. Sisa buangan perusahaan ini adalah seperti kepala, ekor atau sirip ikan yang sudah tidak digunakan lagi. Makanan ini boleh diberi terus kepada ikan keli, malah ada juga yang mencampurkan dedak halus dan direbus sehingga separuh masak apabila telah sejuk.

Siput
Siput merupakan musuh utama penterrnakan ikan air tawar. Siput-siput yang banyak ini boleh dijadikan makanan ikan keli ini. Siput-siput ini perlu diasingkan dari cengkerangnya sebelum diberi kepada ikan keli. Kemudian, siput direbus selama beberapa minit kemudian isinya dicungkil keluar dari cengkerangnya dengan menggunakan alat yang runcing.

Pelaburan dan keuntungan pengeluaran ikan keli
Untuk menjalankan penternakan ikan keli ini, anggaran kos yang diperlukan haruslah diketahui dengan jelas bagi memperolehi pulangan yang lumayan.
Untuk memudahkan pelaksanaannya, perhitungan analisis ini perlu disesuaikan dengan tahap kegiatan yang biasa dilakukan. Analisis merangkumi proses pembenihan, pemeliharaan dan pembesaran.

Analisis proses pembenihan
Analisis proses pembenihan ikan keli dihitung untuk jangka masa pengeluaran. Proses pengeluaran ikan keli tempatan memerlukan lebih kurang 1.5 bulan yang meliputi kegiatan penyediaan, pensenyawaan, penetasan telur (4 hari), pemeliharaan benih (30 hari) dan bakinya adalah untuk pengeringan kolam pembenihan. Jumlah induk yang disenyawakan adalah sebanyak 10 pasang. Analisis yang lengkap adalah seperti berikut.

Pelaburan
1. Kemudahan
- 10 buah tangki berukuran 2m x 1m x 0.6m =RM 750.00
- Sewa kolam 1 tahun 200/10,000 x RM 500.00 =RM 40.00
- 1 set peralatan perikanan =RM 190.00
- 10 pasang induk ikan keli @ RM10.00 =RM 100.00
JUMLAH RM 1,080.00

2. Modal kerja
- 4 beg najis ayam @ RM2.00 =RM 8.00
- 2 kg baja urea @ RM1.00 =RM 2.00
- 2 kg baja TSP @ RM1.00 =RM 2.00
- 10 kg kapur pertanian @ RM0.50 =RM 5.00
- 5 liter cacing sutera @ RM2.00 =RM 10.00
- 10 kg serbuk palet @ RM3.00 =RM 30.00
- 20 kg butiran palet @ RM1.20 =RM 24.00
- 1 tenaga pekerja sambilan @ RM230.00 =RM 230.00, JUMLAH =RM 311.00
JUMLAH PELABURAN 1 + 2 =RM 1,391.00

a. Kos tetap
1. Penyusutan/Sewa kolam
- Tangki tembok 1.5/12 x RM750.00 =RM 93.75
- Sewa kolam 1.5/12 x RM500.00 =RM 62.50
- Peralatan perikanan 1.5/24 x RM190.00 =RM 25.00
- Induk ikan keli 40% x RM100.00 =RM 40.00
Jumlah =RM 221.25

2. Faedah modal
2.5 % x 1.5 bulan x RM 1380.00 =RM 51.75
Jumlah kos tetap (1+2) =RM 273.00
b. Jumlah Kos Pengeluaran
- Modal kerja =RM 311.00
- Kos tetap =RM 273.00
Jumlah =RM 584.00

c. Penjualan
- Benih ikan keli berukuran 5-8 cm 10,400 ekor @ RM0.30 =RM 3,120.00

d. Analisis
1. Keuntungan
- Penerimaan =RM 3,120.00
- Jumlah kos pengeluaran =RM 584.00
Keuntungan =RM 2,536.00
2. Aliran tunai (cash flow)
- Keuntungan =RM 2,536.00
- Kos pengurangan / sewa kolam =RM 221.25
Jumlah =RM 2,757.25
3. Tempoh bayaran balik modal (pay back peiod)
= Jumlah pelaburan X bulan
Keuntungan= RM 1391.00/RM 2604.50 X 1.5 bulan = 0.8 bulan

f. Analisis R/C dan BEP
1. Revenue cost ratio (R/C)= Penerimaan/Jumlah kos = RM 3120.00/RM 584.00 = 5.3
2. BEP
BEP = Kos tetap/1 – Kos berubah/Jumlah jualan = RM 273.00/ 1 – RM 311.00/RM 3120.00
= RM 273.00 atau = RM 273.00 / RM 0.90 = 303 ekor

Analisis proses pembesaran
a. Pelaburan
1. Kemudahan
- Sewa kolam 1 tahun 400m2 / 1000m2 x RM 500.00 =RM 75.00
- Pondok jaga 1 buah =RM 675.00
- Pengisar daging =RM 75.00
- 1 set peralatan perikanan =RM 150.00
Jumlah =RM 975.00

2. Modal kerja
- 4 beg najis ayam 2 RM 2.00 =RM 8.00
- 3 kg baja urea @ RM 0.60 =RM 1.80
- 3 kg baja TSP @ RM0.80 =RM 2.50
-18 kg kapur @ RM 0.50 =RM 7.00
- 8000 ekor benih ikan keli @ RM0.30 =RM 450.00
- 400 kg pellet @ RM1.00 =RM 400.00
- 600 kg makanan alternative (ikan rucah) @ RM0.30 =RM 180.00
- Tenaga pekerja tetap 1 org x 5 bulan x RM100.00 =RM 500.00
- Tenaga pekerja harian 6 org @ RM10.00 =RM 60.00
Jumlah= RM 1,609.30
Jumlah pelaburan (1+2)= RM 2,584.30

b. Kos tetap
1. Pengurangan / Sewa kolam
- Sewa kolam 6/12 x RM 500.00 =RM 250.00
- Pondok jaga 6/42 bulan x RM 675.00 =RM 96.00
- Pengisar daging 6/24 bulan x RM100.00 =RM 25.00
- Peralatan perikanan 6/24 bulan x RM300.00 =RM 75.00
Jumlah =RM 446.00

2. Faedah bank
25% x 6 bulan x RM 2887.00 =RM 64.61
Jumlah kos tetap (1 +2) =RM 510.61

c. Jumlah kos pengeluaran
- Modal kerja =RM 1,609.30
- Kos tetap =RM 510.61

d. Penjualan
- Ikan keli dengan berat 800kg @RM5.00 =RM 4,000.00

e. Analisis
1. Keuntungan
- Penerimaan =RM 4,000.00
- Jumlah kos pengeluaran =RM 2,119.91
Keuntungan =RM 1,880.09
2. Aliran tunai (cash flow)
- Keuntungan =RM 1,880.09
- Kos penyusutan / sewa kolam =RM 250.00
Jumlah =RM 2,130.09
3. Tempoh bayaran balik modal ( pay back period)
= Jumlah pelaburan/Keuntungan X bulan
= RM 2584.00/RM 1880.09 X 6 bulan
= 8.24 bulan

f. Analisis R/C dan BEP
1. Revenue cost ratio (R/C)
= Penerimaan/Jumlah kos
= RM 4000.00/RM 2119.91 = 1.9
2. BEP
BEP = Kos tetap/1 – Kos berubah/Jumlah jualan = RM 510.61/1 – RM 1609.30/RM 4000.00
= RM 510.61 atau RM 510.61/0.6 = RM 851

Pasaran / Kesimpulan
1. Permintaan terhadap ikan keli yang semakin meningkat telah menaikkan semangat para penternak untuk menghasilkan ikan tersebut.
2. Pasaran ikan keli tidak terbatas untuk keperluan pengguna di rumah sahaja, malah restoran dan hotel-hotel turut mendapat sambutan.
3. Pemeliharaan adalah proses penjagaan benih ikan keli yang dihasilkan dari proses pembenihan untuk dipelihara dalam jangka masa tertentu sehingga berukuran di antara 3-5 cm atau 5-8cm seekor.
4. Pembesaran pula proses pemeliharaan ikan keli yang telah melalui proses pemeliharaan untuk dijaga dalam jangka waktu tertentu sehingga ia boleh dipasarkan. Ukurannya di antara 6-12 ekor/kg. Biasanya ikan yang dipasarka adalah 6-8 ekor/kg.

Kaedah Penyuntikan Ikan Keli

2009-03-02T10:16:00.002+08:00

Mengenal Ikan keli
Ikan keli menurut klasifikasi berdasarkan taksonomi yang dikemukan oleh Weber de Beaufort(1965) digolongkan sebagai berikut ;
Chordata, ialah binatang bertulang belakang Pisces, ialah bangsa ikan yang mempunyai insang untuk bernafas.
Teleostei, ikan yang bertulang keras.
Ostariophysi, ialah ikan yang di dalam rongga perutnya sebelah atas memiliki tulang sebagai alat perlengkapan keseimbangan yang disebut tulang weber Siliroide, ikan yang bentuk tubuhnya memanjang berkulit licin(tidak bersisik)
Clarridae ialah satu kelompok yang selain mempunyai ciri tersebut dan bentuk kepalanya yang pipih dengan tulang keras sebagai pelindung kepala. Bersungut 4 pasang. Sirip dada. Mempunyai alat pernafasan tambahan yang terletak dibahagian depan rongga insang yang membolehkan ikan keli bernafas.

Penyebaran
Ikan keli tersebar luas di benua Afrika dan Asia, terdapat diperairan umum yang berair tawar secara liar. Di beberapa negara, khususnya di Asia. Ikan keli telah diternak, dipelihara di kolam. Seperti di Filipina, Thailand, Indonesia, Laos, Kemboja,Burma dan India.

Habitat
Habitat atau lingkungan hidup ikan keli ialah semua perairan air tawar. Di sungai yang airnya tidak terlalu deras, atau di perairan yang tenang seperti danau, telaga, serta kolam-kolam kecil.
Ikan keli mempunyai insang tambahan yang membantu ikan ini bernafas untuk mendapatkan bekalan oksigen. Oleh itu, ikan keli sangat tahan di perairan yang mengandungi bekalan oksigen yang sedikit. Ikan keli juga tahan terhadap pencemaran bahan-bahan organik. Oleh itu, ikan keli amat tahan di dalam air yang kotor.

Perlakuan Ikan keli
Ikan keli yang hidup di air tawar, bersifat nocturnal iaitu aktif pada waktu malam dan menyukai kawasan yang gelap. Pada siang hari, ikan keli lebih suka berdiam diri di dalam lubang-lubang atau tempat yang tenang dan aliran air yang tidak terlalu deras.
Ikan keli membuat sarang di dalam lubang-lubang di tepi sungai, permatang sawah dan kolam yang teduh dan tenang.

Teknik Pembenihan
Secara umumnya ikan keli membiak dengan meletakkan telurnya di dalam sarang. Sarang ikan keli berupa lubang yang dibuat pada dinding permatang sawah, tepian sawah. Kerapkali sarang ikan keli terdapat di bawah rumpun tumbuh-tumbuhan air yang tenang dan terlindung.
Kebanyakan penternak meniru cara kehidupan ikan keli ini dengan menciptakan keadaan lingkungan yang sama untuk ikan keli bersenyawa. Di dalam kolam pemeliharaan, induk ikan keli disediakan kotak-kotak kayu atau buluh yang ditenggelamkan ke dasar kolam.
Untuk memudahkan proses pensenyawaan dan pemungutan hasil, penternak-penternak mengubahsuai kotak-kotak tersebut sama dengan kehidupan sebenar ikan keli.
Salah satu contoh teknik pensenyawaan penternak di Asia.

A. Sistem Blitar
Di sekeliling tepi kolam pemeliharaan induk itu dibuat bilik-bilik atau kotak pensenyawaan.
Contoh pengukuran kolam adalah sepereti berikut;
Panjang : 10-15meter
Lebar : 8-10meter
Kedalaman : 1-1.5 meter
Dinding kolam diperbuat dari bata yang disimen untuk keseluruhan kolam.
Setelah dasar kolam disimen, sebaiknya diberi lapisan pasir bercampur tanah liat setebal 10cm untuk mewujudkan suasana yang sama dengan habitat asal ikan keli.
Untuk mengelakkan ikan keli tidak merayap keluar, terutama waktu hujan turun, di bibir kolam dipasang dinding dari plastik yang licin dan didirikan tegak lurus setinggi 50cm.
Paip kemasukan air ke dalam kolam dapat dibuat dari PVC atau buluh. Cara pemasangan dibuat dengan membuat kecerunan sedikit untuk menambahkan kandungan udara ke dalam air dengan cukup baik serta boleh menyegarkan ikan-ikan.
Untuk pengeluaran air dari kolam, dibuat pintu bentuk monnik. Dinding pintu air itu mempunyai 3 lapisan. Dinding yang mengadap kolam lubangnya di dasar, sehingga air yang terbuang keluar adalah dari bahagian lapisan dasar yang banyak kotorannya. Sekatan di tengah terdiri daripada papan-papan yang disusun dan dapat digunakan untuk mengatur ketinggian air di dalam kolam. Dengan itu air boleh mengalir keluar melalui saluran tersebut.
Permukaan air di dalam kolam itu hendaklah tidak melebihi 20 cm dari bibir kolam, supaya ikan keli tidak mudah melompat keluar.

Kotak pensenyawaan
Untuk ukuran kotak pensenyawaan pula adalah ;
Lebar : 50 cm
Panjang : 50 cm
Kedalaman : 60 cm
Kotak-kotak ini diperbuat daripada simen. Pada dinding dalam mengadap ke kolam induk, 2 lubang yang bergaris tengah 15 cm. Jarak kedua lubang itu 15 cm. Lubang ini sebagai jalan masuk ke dalam kotak itu bagi ikan keli untuk bersenyawa.
Pada dinding belakang iaitu yang mengadap keluar kolam dibuat 1 atau 2 buah lubang yang terletak di dasar kotak itu. Tujuannya adalah untuk memudahkan proses pengeringan dan pengasingan benih-benih ikan keli. Lubang itu dapat disumbat dan dibuka dengan mudah.
Kotak pensenyawaan itu perlu ditutup dengan kayu yang mudah dibuka untuk proses pembersihan. Penutup tersebut perlu disediakan lubang-lubang kecil untuk memberi sedikit ruang udara kepada ikan keli disamping untuk mengekalkan ruang yang gelap
Jarak di antara kotak pensenyawaan adalah 75 cm – 100 cm. Ini bertujuan untuk mengelakkan ikan keli yang bersenyawa tidak diganggu oleh yang lain.
Kotak diletakkan di bahagian atas kolam berdekatan dengan tepi kolam sehingga kedalaman air di dalam kotak pensenyawaan itu hanya 30 cm.
Dasar kotak pensenyawaan itu perlu dialas pasir, tetapi tidak berlumpur. Pastikan pasir yag lembut dan bersih, supaya induk tidak rosak semasa proses pensenyawaan. Lapisan pasir ini bertujuan untuk induk meletakkan telur. Kebersihan perlu dijaga untuk mengelakkan telur-telur ikan keli dijangkiti bakteria-bakteria.
Di dalam kotak pensenyawaan elok juga diberi sedikit ijuk, yang diletakkan diatas pasir. Sebelum dimasukkan, ijuk dicuci dan dijemur. Telur-telur ikan keli akan tersebar di antara serabut-serabut ijuk, tetapi tidak meletak kuat.

Contoh kaedah pengairan di Indonesia.
Satu kaedah untuk pengairan air untuk memastikan berada pada paras kita kehendaki dengan menggunakan bilah-bilah papan disusun mengikut peringkat-peringkat yang ditetapkan untuk kedalaman air iaitu salah satu kaedah di Indonesia, untuk mengawal air secara manual dengan menggunakan papan.

Pengaturan air kolam pensenyawaan.
Di dalam kolam pensenyawaan ini, ikan keli memerlukan keadaan air yang segar dan bersih, mengandungi cukup oksigen dan tidak mengandungi bahan pencemar untuk mendapatkan hasil benih yang baik. Pastikan air yang digunakan tidak mengandungi air cucian sabun dan detergen. Ini sangat berbahaya terhadap ikan keli dan perlu dipastikan setiap masa.
Apabila air menjadi keruh, air tersebut perlu diendapkan dan disaring terlebih dahulu. Di depan paip kemasukan air perlu dipasangkan saringan (filter) yang dapat menyekat kotoran.

Induk ikan keli.
Calon- calon ikan keli dapat diperolehi bila ukuranya mencapai 100 gram atau lebih. Calon-calon induk sebesar ukuran tersebut dapat diperoleh setelah ikan keli berumur 4 bulan, jika makanan yang diberikan bermutu tinggi, ikan keli boleh hmencapai 100 gram selepas berumur sebulan.
Untuk mendapatkan induk yang baik, ikan keli dipilih daripada gerak gerinya, badan yang kilat dan gemuk.

Alat kelamin ikan keli jantan dan betina terletak di belakang luang dubur, terdapat bonjolan. Pada betina, tonjolan itu berbentuk bulat. Manakala bonjolan tersebut membujur untuk jantan.
Menurut daripada penternak-penternak ikan keli, ikan keli akan menunjukkan tanda-tanda sebagai berikut;

Induk jantan
1. Alat kelamin nampak jelas dan membujur(meruncing)
2. Perutnya nampak meramping, jika perut diurut(ditekan perlahan-lahan) spermanya akan keluar.
3. Tulang kepala lebih mendatar dibandingkan dengan betina.
4. Jika warna dasar badannya hitam, warna itu menjadi lebih gelap daripada biasanya.

Induk betina
1. Alat kelamin berbentuk bulat dan kemerahan, lubangnya agak membesar.
2. Tulang kepala agak cembung.
3. Pergerakan agak lambat berbanding dengan ikan jantan.
4. Warna badanya lebih cerah dari biasanya.
Perbezaan diantara jantina adalah bentuk kelaminnya, dimana alat kelamin jantan lebih berbentuk bujur berbanding bentuk kelamin betina yang berbentuk bulat.
Dalam satu kolam pensenyawaan yang luasnya 100m2 dapat dipelihara induk keli sebanyak 25 pasang (25 ekor betina dan 25 ekor jantan)

Musim pensenyawaan
Pensenyawaan ikan keli banyak terjadi pada musim hujan.Tetapi menurut pengalaman penternak ikan, ikan keli dapat bersenyawa sepanjang tahun, apabila keadaan air kolam sering berganti. Pensenyawaan juga dipengaruhi oleh makanan yang diberikan. Makanan yang bermutu baik akan meningkatkan vitamin ikan sehingga ikan sering bersenyawa.

Pemeliharaan induk
Pemeliharaan dan rawatan calon induk dan induk ikan keli mesti berada dalam keadaan sihat, tidak mudah diserang penyakit, supaya dapat menghasilkan keturunan yang sihat. Untuk tujuan tersebut pelbgai cara telah digunakan, di antaranya adalah;
1. Mengatur air kolam agar sering diganti, walaupun kemasukan air tidak terlalu deras. Kemasukan air 5-6 liter per minit sudah mencukupi untuk menyegarkan ikan keli.
2. Makanan yang bermutu baik dan jumlah yang mencukupi. Makanan bagi ikan keli berupa makanan asas dan makanan tambahan.
Makanan asas ikan keli terdiri dari berbagai jenis, antaranya adalah (Copepoda, Cladocera), larva atau jentik-jentik, serangga, cacing dan sebagainya.

Ikan keli Cat Fish
Ikan keli Cat Fish ( Clarias gariepinus) iaitu raja ikan keli. Ikan keli ini memang mempunyai sifat-sifat yang baik, pertumbuhannya juga sangat cepat dan mencapai ukuran besar dalam waktu yang pendek.

Sifat-sifat cat fish.
Clarias gariepinus(cat fish)
- Warna badan ikan keli menjadi perangkeperangan jika ikan terkejut atau dalam keadaa stress.
- Gerakannya lebih agresif
- Sengat ikan keli ini tidak beracun
- Tidak merosakkan benteng jika diternak di dalam kolam benteng.

Clarias batrachus(ikan keli biasa)
- Warna gelap
- Gerakan biasa
- Sengat berbisa
- Merosakkan benteng kolam.

Pertumbuhan
Umur ---------- Cat fish (gram) ---------- Ikan keli biasa
2 hari (larva) ------ 2 – 3 ---------------------- 1 – 2
5 minggu --------- 10 – 15 -------------------- 1 – 5
24 minggu ------- 180 - 200 ------------------ 40 – 50

Data pertumbuhan ini diperolehi dari sumber penternak, dengan kolam 1000 m2 berkedalaman 1 meter, benih 5 – 8 cm, kepadatan penebaran 30 -50 ekor/m2 selama 24 mingu(5 -6 bulan) menghasilkan cat fish seberat 200-300 gram/ekor.

Teknik penyuntikan
Teknik penyuntikan hormon
Ikan keli(cat fish) merupakan induk daripada Clarias gariepinus dan induk betina clarias fuscus.
Tujuan teknik penyuntikan ini adalah ;
1. Dapat mengkahwinkan 2 jenis induk ikan keli, supaya mendapat baka yang baik.
2. Dapat menghasilkan induk hasil dari 2 induk yang berlainan dan cara hidup yang berbeza sebelum ini.
3. Memperolehi benih bukan hanya di waktu pensenyawaan sahaja.
4. Memperolehi benih mengikut keperluan yang dikehendaki.

Persiapan induk ikan keli untuk disuntik.
Penyuntikan hormon hanya terhasil apabila di dalam ovari ikan keli betina yang telurnya sudah betul-betul matang.
Tanda-tanda induk ikan keli betina yang sudah masak telur adalah seperti berikut ;
1. Perut membesar dan lembut jika dipegang. Perbezaan perut ikan keli yang besar akibat kekenyangan adalah perut ikan besar dan padat, bukan lembut.
2. Dubur agak menonjol dan berwarna kemerahan.
Tanda-tanda ikan keli jantan yang bersedia untuk bersenyawa ;
1. Bahagian perut lansing, jika perut diurut ia akan mengeluarkan cairan putih.
2. Ikan keli jantan tidak perlu disuntik dengan hormon kerana ia mudah untuk
disenyawakan.
3. Induk jantan dan induk betina yang sudah dipilih dikumpulkan secara terpisah di dalam
satu bekas khas.
4. Cara penangkapan induk betina perlu dilakukan dengan berhati-hati kerana ia boleh
mencederakan induk betina sehingga boleh mengeluarkan benih dari induk betina tersebut.
Bagi induk ikan keli jantan, sperma agak sukar dikeluarkan secara urutan. Biasanya ikan keli jantan ini dibunuh, iaitu dibedah rongga perutnya untuk mengeluarkan seluruh kantong spermanya dan seterusnya diletakkan di dalam satu bekas.

Alat-alat yang diperlukan
1. Pisau untuk memotong
2. Gunting
3. Jarum pencungkil
4. Alat suntik
5. Aqua bi-destilata
6. Larutan garam NaCl 0.7%

Mengambil larutan hipofisa
Induk betina ikan keli perlu disuntik dengan satu hormon yang disebut sebagai Gonade Stimulating Hormon(GSH). GSH dihasilkan oleh kelenjar hipofisa atau disebut kelenjar pitiutari. Setiap ikan ( haiwan bertulang belakang) mempunyai kelenjar hipofisa yang terletak di bawah otak. Kelenjar hipofisa ini amat penting dan berfungsi dalam proses pembiakan. Ukurannya kira-kira hanya sebesar sebutir kacang hijau. Beratnya hanya 2-3 mg. Kelenjar hipofisa ini menghasilkan hormon GSH seiring dengan proses dewasa ikan. Ikan keli dewasa mengeluarkan GSH lebih banyak berbanding ikan yang belum dewasa.
Untuk penyuntikan ikan keli, kelenjar hipofisa diambil dari ikan keli yang dikorbankan. Hipofisa boleh diambil dari induk ikan keli biasa iaitu Clarias batracthus.
Kuantiti hipofisa yang perlu disuntik kepada ikan keli cat fish adalah 3 dos. Jika saiz catfish ini 0.5kg, ia memerlukan memerlukan hipofisa dari ikan keli biasa yang berat badannya 3 x 0.5kg. Hipofisa yang diambil boleh daripada induk yang sudah dewasa tidak kira jantan atau betina.

Cara pengambilan hipofisa.
1. Ikan keli biasa dipegang di bahagian kepala. Kepala ikan dipotong dan tulang kepala atas mata ikan keli dikoyakkan sehingga tulang tengkorak terbuka dan otak kelihatan. Otak ini tarik menggunakan twezel dan akan kelihatan kelenjar hipofisa berwarna putih sebesar kacang hijau dibawah otak tersebut.
2. Dengan menggunakan twezel, kelenjar hipofisa itu diangkat dan diletakkan di dalam satu bekas. Kemudian kelenjar hipofisa tersebut dibersihkan dengan menggunakan larutan garam fisologis untuk membersihkan darah yang melekat bersama-sama kelenjar tersebut.
3. Kelenjar hipofisa dihancurkan dan dicampurkan dengan 1-1.5ml aqua bidest. Oleh itu GSH yang terkandung dalam kelenjar hipofisa itu akan terlarut di dalam aqua
bidest(boleh didapati di kedai-kedai ikan).

Cara penyuntikan hipofisa.
1. Penyuntikan ikan betina dibuat dibahagian pungung dekat dengan sirip punggung ke dalam dagingnya.
2. Untuk ikan keli yang beratnya 0.5kg , 3 dos larutan hipofisa tadi yang telah dilarutkan dengan larutan aquabidest 1ml, 1/3 ml disuntik dahulu dan dilepaskan kedalam kolam khas sacara terasing dengan ikan lain. 4 jam kemudian 2/3 larutan hipofisa disuntikkan untuk kali kedua. Dan selepas 3 jam penyuntikan kedua perut induk ikan keli betina diurut untuk mengeluarkan telurnya.

Pembenihan secara buatan
Telur dari induk betina yang sudah disuntik dengan hormone GSH diurut dibahagian perutnya untuk mengeluarkan telur. Kemudian telur ini dicampurkan bersama sperma ikan jantan di dalam satu bekas khas yang bersih.

Cara pengurutan
Induk betina yang sudah 3 jam disuntik hormon(proses teraakhir) tidak boleh lambat diambil dari tempat kolam khasnya kerana boleh menyebabkan telur akan terkeluar ke dalam kolam tersebut dengan sendiri.
Induk ikan tersebut dipegang dibahagian kepala dengan menggunakan kain supaya tidak licin. Sementara tangan kiri memegang kepala ikan, tangan kanan melakukan pengurutan perut ikan itu. Dengan menggunakan ibu jari, telunjuk dan jari hantu, proses menekan dan mengurut ikan dimulakan dari belakang kepala kearah dubur. Telur akan keluar dan ditampung di dalam mangkuk. Pengurutan perut tersebut diulang-ulang 2-3 kali sehingga semua telur induk ikan keli betina tersebut keluar.

Pengeluaran sperma.
Kepala ikan keli jantan dipotong dibahagian belakang sirip dada. Kemudian dengan menggunakan gunting, perut ikan keli jantan digunting sepanjang sisi bawah badannya untuk mengeluarkan usus dan isi perut. Apabila semua isi perut dikeluarkan, maka kantong sperma akan kelihatan berbentuk pipih memanjang seperti pita. Kantong sperma ini dipotong-potong dan dipecah-pecahkan serta diurut-urutkan supaya cairan air mani keluar. Kemudian cairan air mani itu dituangkan ke dalam mangkuk yang sudah diisi dengan telur yang keluar tadi.

Pembuahan
Telur dan air mani di dalam mangkuk tadi dicampur perlahan-lahan dengan menggunakan bulu ayam sehingga campuran tersebut sama rata. Selepas beberapa ketika, telur tersebut akan mengembang dan air perlu ditambah untuk mengelakkan ia menjadi keras. Telur-telur yang disenyawa akan melekat pada bulu ayam.
1) Cara pemotongan ikan keli jantan untuk mengambil larutan hipofisa. Ikan terpaksa dipotong dibahagian kepala iaitu bahagian tengkuk ikan keli.
2) Tengkorak ikan keli jantan digoreskan untuk mendapat hifopisa dan diangkat menggunakan twezel
3) Larutan hipofisa yang diperolehi tadi, disuntik kepada induk betina. Rujuk langkah- langkah untuk proses penyuntikan seperti yang dinyatakan sebelum ini.
4) Kemudian perut induk jantan tadi dipotong untuk mengambil sperma.
5) Sperma ini di simpan di dalam sebuah tabung.
6) Perut induk betina diurut dengan menggunakan tangan untuk mengeluarkan telur.
7) Sperma dan telur disenyawakan di dalam satu bekas bersih.
8) Selepas persenyawaan berlaku, kaedah penyebaran benih dilakukan di dalam kawasan air yang bersih.

Tilapia

2009-03-01T21:49:00.005+08:00

Some Facts About Tilapia Aquaculture

Tilapia is the common name

for nearly a hundred species. Tilapia comes in several colors, but red and black tilapia are the most well-known species. Skinless and boneless Tilapia of any variety cooks completely white, making it an excellent substitute for nearly any white fish, including: sole, flounder, cod, haddock, pompano and grouper. Both types of tilapia can thrive in either fresh or brackish water (mix of fresh and seawater) Most of the Fresh Tilapia Fillets consumed in the US are produced in Honduras, Ecuador, Colombia, Costa Rica and Brazil and imported fresh daily. Hailed as "the fish of the new millenium" and "the new orange roughy", Tilapia (pronounced Til AH pe ah) has rapidly gained consumer recognition in the United States. Consumption in America, which reached about 145 million lbs. of whole weight in 2000, has been growing at over 35% a year for the past 8 years. Tilapia traces its origin to the Nile River and has been farm raised for decades. Its culinary potential was appreciated by the ancient Egyptians and the epicurean Greeks. Aristotle is believed to have given the fish its name Tilapia niloticus (fish of the Nile) in 300 BC.Legend says that tilapia was the fish Christ multiplied a thousandfold to feed the masses. Tilapia is also referred to as St. Peter's fish. A member of the Cichlid family, these fish look much like a snapper or perch and can live in either fresh or salt water.

Britannica Concise Encyclopedia: Tilapia

Any of numerous, mostly freshwater, fish species (genus Tilapia, family Cichlidae), native to

Africa. They resemble North American sunfishes; one species grows to 20 lbs (9 kg). Tilapia

species are easy to raise and harvest for food; they grow rapidly, resist disease, and eat readily abundant algae and zooplankton. They have been used in warm-water aquaculture systems since the early Egyptian civilization and have been introduced into many freshwater habitats.

Columbia Encyclopedia: tilapia

tilapia (t?lä'pe?) or St. Peter's fish, a spiny-finned freshwater fish of the family Cichlidae, native chiefly to Africa and the Middle East. Fish of the genera Oreochromis, Sarotherodon, and Tilapia, all commonly known as tilapias, have laterally compressed bodies like those of sunfish, are fast growing, and tolerate brackish water. True tilapias are nest brooders, but species of the other genera incubate their eggs orally; one or both parents carry them in their mouths until (and for a short period after) the young hatch. They are economically important as food fishes, both in their native regions and elsewhere, where they have been introduced or are grown on fish farms. The Nile tilapia (Oreochromis niloticus) may have been farmed in ancient Egypt, and the most commercially important tilapia of aquaculture areOreochromis species and their hybrids.Tilapias have a mild-tasting flesh, but the skin has a bitter flavor. Tilapias are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Perciformes,family Cichlidae.'Tilapia' (pronounced /t??l?pi?/) is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapias inhabit a variety of fresh and, less commonly, brackish water habitats from shallow streams and ponds through to rivers, lakes, and estuaries. Most tilapias are omnivorous with a preference for soft aquatic vegetation and detritus. They have historically been of major importance in artisanal fishing in Africa and the Levant, and are of increasing importance in aquaculture around the world.Where tilapia have been deliberately or accidentally introduced, they have frequently become problematic invasive species.

Etymology

The common name tilapia is based on the name of the cichlid genus Tilapia, which is itself a latinization of thiape, the Tswana word for "fish".The genus name and term was first introduced by Scottish zoologist Andrew Smith in 1840. As they have been introduced globally for human consumption, tilapia often are referred to by specific names in various languages and dialects. Certain species of tilapia are sometimes called "St. Peter's fish." This term is taken from the account in the Christian Bible about the apostle Peter catching a fish that carried a shekel coin in its mouth. However, no species of fish is named in that passage of the Bible.While that name is also applied to Zeus faber, a marine fish not found in the area, one tilapia (Sarotherodon galilaeus galilaeus) is known to be found in Sea of Galilee where the account took place. This particul

ar species is known to have been the target of small-scale artisanal fisheries in the area for thousands of years.In some Asia n countries including the Philippines, large tilapia are often referred to as pla-pla while their smaller brethren are still referred to as tilapia.In Hebrew, tilapia are called amnoon (?????). In Arabic, tilapia are called mush? (???) (comb) because

of its comb-like tail. It is called jilaebi in Tamil.

Types of Tilapia

There are many varieties of tilapia. However, the two best suited for aquaculture are the red

tilapia (Oreochromis mossambica) and the black tilapia (Oreochromis niloticus). Although both

strains can be raised in either fresh or brackish water, black tilapia usually are most suited to

the fresh water than the red. The fillets are only slightly different in color. Fillets of both red and black tilapia, when raised correctly, will have a similar, mild taste. Since Tilapia absorbs flavor from the water its raised in, wild tilapia can have a muddy or inconsistent flavor while aquacultured tilapia with reliable water sources, the right feed, and carefully monitored growth will taste mild and sweet. It is important to buy tilapia from a company with a reliable water source. the genetic strain " Tilapia/Nile Nilotica", generally considered the best for cultivation. tilapia fish are harvested after one year of growth at an average weight of two pounds. tilapia are fed an all-natural, nutritionally balanced diet of grain and protein. Tilapia fillets are white, firm, and moist. They are very mild in flavor and accept sauces well. water sources ensure a very mild, delicate taste, a taste and texture similar to sole. Tilapia can also be used successfully in recipes calling for snapper, sole, cod, haddock, pompano, flounder, sea bass,ororange roughy. Easily poached, broiled, sauteed, grilled, baked, microwaved, steamed, fried, "blackened", stir-fried, or as an ingredient in bouillabaisse and other fish soups, Rain Forest Tilapia makes a very versatile menu item, and is a popular and nutritious fish for the whole family. Tilapia, several species and their hybrids of Oreochromis, are the second most important group of farm raised fish in the world. Tilapia farming and consumption are rapidly increasing in the US. Tilapia is now the fifth most popular seafood consumed in the United States and has become the third most important fish in aquaculture after carps and salmonids, with production reaching 1,505,804 metric tons in 2002. Because of their large size, rapid growth, and palatability, a number of tilapiine cichlids are at the focus of major aquaculture efforts, specifically various species of Oreochromis, Sarotherodon, and Tilapia, collectively known colloquially as tilapias. Like other large fish, Consumers widely agree that Fresh Tilapia Fillets are an excellent addition to a healthy diet. Fresh Tilapia fillets low in fat, low calorie, low carbohydrate and are high in protein.

Fresh Tilapia fillets are also an excellent source of Phosphorus, Niacin, Selenium, Vitamin B12 and Potassium.they are a good source of protein and a popular target for artisanal and commercial fisheries. Originally, the majority of such fisheries were in Africa, but accidental and deliberate introductions of tilapia into freshwater lakes in Asia have led to outdoor aquaculturing projects in countries with a tropical climate such as Papua New Guinea, the Philippines, and Indonesia. In temperate zone localities, tilapiine farming operations require energy to warm the water to the tropical temperatures these fish require. One method i nvolves warming the water using waste heat from factories and power stations. Tilapiines are also among the easiest and most profitable fish to farm. This is due to their omnivorous diet, mode of reproduction (the fry do not pass through a planktonic phase), tolerance of high stocking density, and rapid growth. In some regions the fish can be put out in the rice fields when rice is planted, and will have grown toedible size (12–15 cm, 5–6 inches) when the rice is ready for harvest. One recent estimate for the FAO puts annual production of tilapia at about 1.5 million tonnes, a quantity comparable to the annual production of farmed salmon and trout.Unlike salmon, which rely on high-protein feeds based on fish or meat, commercially important tilapiine species eat a vegetable or cereal based diet. Tilapias raised in inland tanks or channels are considered safe for the environment, since their waste and disease should be contained and not spread to the wild. Set against their value as food, tilapiines have acquired notoriety as being among the most serious invasive species in many subtropical and tropical parts of the world. For example Oreochromis aureus, Oreochromis mossambicus, Sarotherodon melanotheron melanotheron, Tilapia mariae, and Tilapia zilli have all become established in the southern United States, particularly in Florida and Texas.

Tilapia farming

Large-scale commercial culture of tilapia is limited almost exclusively to the culture of three

species: Oreochromis niloticus, O. mossambica and O. aureus. Of the three tilapia species with

recognized aquaculture potential, the Nile tilapia, O. niloticus, is by far the most commonly used species in fish farming. Growout strategies for tilapia range from the simple to the very complex. Simple strategies are characterized by little control over water quality and food supply and by low fish yields. As greater control over water quality and fish nutrition are imposed, the production cost and fish yield per unit area increases.Across this spectrum, there is a progression from low to high management intensity.

In traditioanal pond culture of tilapia, proper environmental conditions are maintained by

balancing the inputs of feed with the natural assimilative capacity of the pond. The pond’s

natural biological productivity (algae, higher plants, zooplankton and bacteria) serves as a biological filter that converts the wastes through natural biological processes. Tilapia has been

farm-raised as far back as ancient Egypt, and now such farming occurs in more than 85 countries.

Tilapia is considered sustainable thanks to its herbivore eating habits, feeding mainly on plankton, filamentous algae, aquatic macrophytes and other vegetable matter. As a result, wild tilapia does not accumulate pollutants and other toxins in their bodies. On fish farms Tilapia are fed mostly on grain and are also prone to be toxin-free. Tilapia is rapidly becoming one of the most popular seafood in the United States, with the National Marine Fisheries Service ranking it the fifth most consumed seafood. In fact, American’s annual consumption of tilapia has quadrupled over the last 4 years, from a quarter pound per person in 2003 to more than a pound in 2007. Researchers predict tilapia is destined to be one of the most important farmed seafood products of the century.

Pacific Aquaculture

Ponds are the traditional and inexpensive way to hold spawning populations of broodfish. In some parts of the world, the pond system has been made more efficient through the use of cages or net enclosures (hapas). Basically, the hapas are fine mesh net enclosures that are about 40 square meters in size and arranged into units within a larger pond. This segregates the pond into more easily managed units. On a per unit area basis, tanks are the most efficient method of collecting and raising fry, followed by hapas and simple ponds. In aquaculture, no two situations are alike. Each project must be carefully crafted to meet the expectations of the owners, while giving diligent consideration to the limitations and strengths inherent in the proposed venture.

Farm-raised Oreochromis niloticus

Oreochromis niloticus are a species native to Africa and as one of the tilapia species with the

Northern most range, it is tolerant of lower temperatures than many other species.

The O.NIloticus is one of the major species used in tilapia production round the world and is used in many hybrid crosses. As pond production intensifies and feed rates increase, supplemental aeration and some water exchange are required to maintain good water quality. For densities above 1.5-kg per square meter, aeration is usually required. There is a point where the incremental returns are not worthy of the additional inputs and risks. Increasing the intensity of the system does not necessarily reflect an increase in profitability. All tilapia production syst

ems must provide a suitable environment to promote the growth of the aquatic crop. Critical environmental parameters include the concentrations of dissolved oxygen, un-ionized ammonia nitrogen, nitrite nitrogen, and carbon dioxide in the water. Other important parameters include nitrate concentration, pH, and alkalinity levels within the system. To produce tilapia in a cost effective manner, production systems must be capable of maintaining proper levels of these water quality variables during periods of rapid fish growth. To provide for such growth, tilapia are fed high protein pelleted diets at rates ranging from 1.0% to 30% of their body weight per day depending upon their size and species. Numerous options for holding broodfish, fry, fingerlings, juveniles, sub-adult and adult tilapias are available to the prospective farmer. The options include ponds, tanks, raceways, hapas and cages. Tanks and raceways involve considerably greater expense to construct but offer greater control. They are usually used in intensive and super-intensive culture of tilapi as. Ponds are much cheaper to construct and allow management to stimulate natural productivity more readily. The major drawback of pond culture of tilapias is the greater risk of uncontrolled reproduction, which will occur if certain measures are not taken to minimize this possibility. Ponds are used in extensive, semi-intensive and intensive tilapia production.Pond culture is by far the most common method being employed throughout Latin America because it is the cheapest method and also is one of the best.

Noxious pest

Impacts on Australian rivers, creeks and ponds have been great, particularly the dramatic decreases in native fish populations due to predation and competition for food by the fast breeding tilapia that consume a vast range of food sources. Further habitat impacts include increases in local turbidity levels from nesting behaviours. Native fish, invertebrates, and other organisms also experience reduced access to cover through the aggressive territorial de fence of breeding and feeding sites by some tilapia species. Tilapia are listed as a noxious pest in Queensland, Australia,and are spreading rapidly into previously untouched and relatively pristine river systems such as the Endeavour River near Cooktown and the Eureka Creek, a tributary to the Walsh, which runs into the Mitchell. As tilapia can thrive in fresh, brackish and salt water, it is thought that infestation in one river can lead to infestation of neighbouring rivers by the fish swimming from the mouth of one to the other through the sea. A number of tilapiine cichlids that are native to Africa and the Levant have been widely introduced into tropical fresh and brackish waters around the world. In some cases, the introductions were deliberate, for example to control invasive aquatic plants, as in the U.S. states of Florida and Texas. Across much of Asia and Africa they have been introduced into ponds and waterways for the purposes of aquaculture. In other cases, unwanted fish have been released by aquarists or ornamental fish farmers into the wild. Because tilapiine cichlids are generally large, fast growing, breed rapidly, and tolerate a wide variety of water conditions

(even marine conditions), once introduced into a habitat they generally establish themselves very quickly. In doing so they compete with native fish fauna, create turbidity in the water

(by digging) thus reducing the light available for aquatic plants, and eating certain types of aquatic plants causing changes in local aquatic flora. Such problems have been observed in many different places, including Australia, Philippines, and the United States.

Galapagos Islands, Ecuador

Tilapia have been introduced to Laguna Junco, an older volcanic caldera. There are no native

freshwater fish in the Galapagos, but there are several native invertebrates that spend all or

part of their lifecycle in freshwater. At least one, the Galapagos dragonfly, is endemic. Tilapia

must be presumed to pose a threat to these invertebrates. The Ecuadorian Park Service is

currently (2007) planning an eradication attempt, with the assistance of US Aid forInternational

Development and the US Geological Survey. Tilapia have been introduced to the mainland of Ecuador, as well as to much of the rest of Latin America, as a fish culture organism.

Singapore

In Singapore, Oreochromis mossambicus was introduced from Java by the Japanese during World War II, hence its local names, Japanese fish and Java fish. It was formerly very abundant in fresh and brackish waters and in the sea off the north coast. However, since the late 1980s, feral tilapiine cichlid populations in most locations have crashed, possibly due to cross breeding with more recently introduced tilapiine cichlid hybrids (red tilapia O. mossambicus x O.niloticus,

possibly also O. honorum and O. aureus). The offspring of the crosses may be strongly sex skewed in favor of males,

and inter-species crosses tend to produce fewer fry per brood than single species spawns, thus causing the population to decline, and hybrids with

O. niloticus may inherit the lower salinity tolerance of that species, thus restricting the habitats where these tilapiine cichlids are found.

United States

Salton Sea in Southern California is home to a large population of Oreochromis mossambicus

known locally as Salton Sea tilapia. How they got into the Salton Sea is not known for certain. The Salton Sea tilapia feed on plant material, phytoplankton (particularly diatoms), copepods, rotifers, barnacle larvae, and small annelid worms. One peculiarity of the Salton Sea are the periodic algal blooms that cause the fish, including the Salton Sea tilapia, to die in massive numbers, causing a particularly nasty smell.There are also populations of tilapia in several lakes in Texas; one in Fairfield lake, another in Martin Creek lake, as well as in Lake Conroe and Stubblefield Lake.

Australia

Shortly after their first importations to Australia in the 1970s aquarium trade, tilapia were introduced into the warm waters of North Queensland dams for weed and mosquito control. Later genetic studies indicated that at least two separate introductions to the native creeks and rivers occurred. As early as 1979, there were established populations of Tilapia mariae and Cichlasoma nigrofasciatum in the cooler climate of Victoria, in a pond warmed by a power station. In 1981 they were also noted to be present in the waters of Carnarvon, Western Australia. Ten years later it was noted that there were established feral populations of tilapia throughout the waters of Queensland and Western Australia, and their geographical range was continuing to increase . By 1991 the waters surrounding the Queensland cities of Brisbane, Townsville, and the Gascoyne River in Western Australia were filled with Oreochromis mossambicus. It was also found that Tilapia mariae was a much less commonly found exotic, though its trapping in rivers north of Cairns indicated that at the time it was possibly extending its range into its preferred water temperature ranges, and that it had a great capacity for tolerating a wide range of salinity levels.

Tilapia as a food fish.

Apart from the very few species found in the Levant, such as Sarotherodon galilaeus galilaeus,

there are no tilapiine cichlids endemic to Asia. However, species originally from Africa have

been widely introduced and have become economically important as food fish in many countries.

China, the Philippines, Taiwan, Indonesia and Thailand are the leading suppliers and these

countries altogether produced about 1.1 million metric tonnes of fish in 2001, constituting about

76% of the total aquaculture production of tilapia world wide.

Taiwan

In Taiwan, tilapiine cichlids are also known as the "South Pacific crucian carp," and since their

introduction, have spread across aquatic environments all over the island. Introduced in 1946,

tilapiine cichlids made a considerable economic contribution, not only by providing the Taiwanese people with food, but also by allowing the island's fish farmers to break into key

markets such as Japan and the United States. Indeed, tilapiine cichlids have become an important farmed fish in Taiwan for both export and domestic consumption.The Chinese name for the fish in Taiwan is "Wu-Kuo" (??) and was created from the surnames of Wu Chen-hui

(???) and Kuo Chi-chang (???), who introduced the fish into Taiwan from Singapore. The

Taiwan tilapia is a hybrid of Oreochromis mossambicus and Oreochromis niloticus niloticus. In

mainland China, it is called Luofei fish (???), named after the origin of this fish: the Nile and

Africa (niLUO and FEIzhou in Chinese respectively).

Thailand

Thailand has its share of fish farms and fish pens devoted to the culture of tilapia species. In

March 2007, millions of caged tilapia in the Chao Phraya river died as the result of a massive

fish kill. The cause for this was determined to be oxygen deprivation on a massive scale, one of

the causes for fish kills.

Philippines

Tilapia, referred to as St. Peter's fish, is one the most preferred fish among Filipinos. In

terms of production, it outranks milkfish (bangus) as the top cultured fish in the country. There are three types of Tilapia: red, Nile and Javanese. In the Philippines, Nile tilapia is the most common. According to Dr. Crispino Saclauso, national team leader for the Aquaculture Network coordinated by the Bureau of Agricultural Research (BAR), the culture of tilapia in the Philippines began as early as the 1950s with the introduction of Oreochromis mossambicus from Thailand. It did not do well during its early cultivation because many growers did not have sufficient information and knowledge on how to properly culture tilapia. Moreover, many growers considered it as nuisance because it competed for the food of milkfish, which at that time was considerably more profitable than tilapia. In the 70s another Nile tilapia from Israel was introduced, this time with promising characteristics. Through sex-reversal the commercial production of tilapia in the country boomed and the tilapia industry experienced a phenomenal growth. In the 90s, there was an erratic production of tilapia due to fishkills and the vulnerability of the fish to various diseases. As the industry expanded, and so were the problems. This urged

scientists and researchers to have a thorough examination of the industry and put emphasis on

developing tilapia varieties that could adopt to certain difficult situations. Several species of tilapia have been introduced into local waterways and farmed for food. Tilapia fish pens are a common sight in almost all the major rivers and lakes in the country, including Laguna de Bay, Taal Lake and Lake Buhi. Locally, tilapia are also known as Pla-Pla. Tilapiine cichlids have many culinary purposes, including fried, inihaw (cooked in charcoal), sinigang (a bouillabaisse which sometimes has tamarind, guava, calamansi or other natural ingredients to flavour it), paksiw (similar to sinigang only it consists of vinegar, garlic, pepper and ginger) and many more recipes.

On January 11, 2008, the Cagayan Bureau of Fisheries and Aquatic Resources (BFAR) stated that tilapia production grew and Cagayan Valley is now the Philippines’ tilapia capital. Production supply grew 37.25% since 2003, with 14,000 metric tons (MT) in 2007. The recent aquaculture congress found that the growth of tilapia production was due to government interventions: provision of fast-growing species, accreditation of private hatcheries to ensure supply of quality fingerlings, establishment of demonstration farms, providing free fingerlings to newly constructed fishponds, and the dissemination of tilapia to Nueva Vizcaya (in Diadi town). Former cycling champion Lupo Alava is a multi-awarded tilapia raiser in Bagabag, Nueva Vizcaya. Chairman Thompson Lantion of the Land Transportation Franchising and Regulatory Board, a retired two-star police general, has fishponds in La Torre, Bayombong, Nueva Vizcaya. Also, Nueva Vizcaya Gov. Luisa Lloren Cuaresma also entered into similar aquaculture endeavors in addition to tilapia production.

Indonesia

In Indonesia, tilapia are known as Ikan Nila. Tilapia was first introduced in Indonesia in 1969 from Taiwan. Later several species also introduced from Thailand (Nila Citralada),Philippines (Nila GIFT) and Japan (Nila JICA). Tilapia has become popular with local fish farmers because they are easy to farm and grow fast. Major tilapia production areas are in West Java and North Sumatra. In 2006, Badan Pengkajian dan Penerapan Teknologi (Agency for the Assessment & Application of Technology) an Indonesian government research body introduced a new species named "genetically supermale Indonesian tilapia" (GESIT). GESIT fish is genetically engineered to hatch eggs that will produce 98% -100% male tilapia. This will benefit fish farmer to farm tilapia with monosex culture (all male) that is more productive.

United States

In the United States, the geographic range for tilapia culture is limited by the temperature-

sensitivity of tilapia. For optimal growth the ideal water temperature range is 82–86 °F, and

growth is reduced greatly below 68 °F. Death occurs below 50 °F. Therefore, only the southernmost states are suitable for tilapia production. In the southern region, tilapia can be held in cages from 5 to 12 months per year, depending on location. Research published in July 2008, suggests the nutritional value of farm raised Tilapia may be compromised due to the amount of corn included in the feed. The corn contains short chain omega-6s that contribute to the buildup of these materials in the fish. "Ratios of long-chain omega-6 to long-chain omega-3, AA to EPA respectively, in tilapia averaged about 11:1, compared to much less than 1:1 (indicating more EPA than AA) in both salmon and trout." The report also observes that the 1.5 million tons of Tilapia were produced in the US in 2005, with 2.5 million tons projected by 2010. Wide spread publicity encouraging people to eat more fish has seen Tilapia being purchased by those with lower incomes who are trying to eat right. The lower amounts of Omega-3 and the higher ratios of Omega-6 compounds in US farmed Tilapia raise questions of the health benefits of consuming this fish.

Marketing the Product

The total aquaculture production of tilapia was reported to be 1,265,800 tons in 2000.

International trade is growing rapidly, especially between Central American producers (Costa

Rica, Ecuador and Honduras) and the United States, and between Asian producers (Taiwan, China, Indonesia and Thailand) and the United States and Japan. There is also modest trade between Jamaica and the United Kingdom. The largest exporter, Taiwan, supplies Japan with high-quality tilapia fillets for the sashimi market, and ships frozen tilapia to the United States market (40,000 tons in 2001). Taiwan exports about 70 percent of its domestic tilapia production. Thailand and Indonesia export less than 5 percent of their production.Viet Nam has also recently entered the world tilapia market, and China exported 12,500 tons to the United States in 2001. Zimbabwe, thanks to the efforts one vertically intigrated operation, now also produces fresh and frozen fillets for the EC market.

Nutrition

Tilapia has very low levels of mercury because it is a fast growing and short lived fish that

mostly eats a vegetarian diet. Farm raised tilapia has very low levels of omega-3, the primary fatty-acid nutrient doctors recommend when eating fish. Farm raised tilapia also has high levels of omega-6 fatty acids. A diet with a high ratio of omega-6 to omega-3 is suspected to cause inflammation, which can be dangerous for those with heart conditions. It is not clear if this poor ratio of omega-6 to omega-3 is due to the inexpensive corn and/or soy based diets typically fed to farm raised Tilapia, the natural fatty acid levels of Tilapia, or a combination of the

two that results in less than desirable fatty acid ratio levels. Tilapia have been used as biological controls for certain aquatic plant problems. They prefer a floating aquatic plant, duckweed (Lemna sp.) but also consume some filamentous alga. In Kenya tilapia were introduced to control mosquitoes which were causing malaria. They consume mosquito larvae, consequently reducing the numbers of adult female mosquitoes, the vector of the disease (Petr 2000). These benefits are, however, frequently outweighed by the negative aspects of tilapia as an invasive species.

In aquaria

The larger tilapias are generally not viewed as good community aquarium fish because they eat

plants and tend to be very disruptive, digging up the substrate and fighting with other fish. The

smaller west African species, such as Tilapia joka, and those species from the crater lakes of

Cameroon are, by contrast, relatively popular. Conversely, in cichlid aquariums tilapias can be

mixed well with non-territorial cichlids, armoured catfish, tinfoil barbs, garpike, and other

robust but peaceful fish. Some species, including Tilapia buttikoferi, Tilapia rendalli, Tilapia joka, and the brackish-water Sarotherodon melanotheron melanotheron, are attractively patterned

and decorative fish.

Aquaculture

2009-02-28T11:27:00.003+08:00

Aquaculture is the name of any type of water or wetland where water animals and plants
are grown. Communities are very reliant on the sea and its resources. Fishing as a source of
income and lifestyle is a part of our peoples tradition and culture. Fish are an important part of
our diet and a good source of income.
But not only on ocean coasts is aquaculture important, in many areas inland aquaculture
provides fish and other products, such as prawns, catfish, eels, taro, watercress and much
more, as food and as an income. Breeding fish is only one part of a healthy aquaculture system.
There are many other factors which keep the system healthy and productive. Water plants,
bacteria, trees and other animals all play important roles in aquaculture systems.

Why is Aquaculture Important?
Aquaculture is very important because it provides so many benefits, such as:
• Fish and other water animals are very good source of protein and nutrition. Even a small pond can provide enough fish to greatly improve the diets and health of a whole family, especially children. The meat can be eaten fresh as it is needed so that it does not go rotten and have to be wasted. Fish can also be sold or dried for later use
• Aquaculture systems will produce more meat for the same area of land than any other animal. This is the most efficient way to produce high quality meat with more protein content
• Aquaculture systems will increase family and community income
• After the fish are harvested, the pond can be cleaned and the soil and manure at the pond bottom can be used as fertilizer for plants, this fertilizer is high quality, rich in nitrogen and very strong, so it should be mixed with water before use. Pond water is also a good source of fertilizer, but it is not very strong. If the ponds are located close to gardens, it will reduce the task of carrying water for watering the garden
• Aquaculture systems are a good way to turn animal manure and waste into fish food and fertilizer for water plants
• Aquaculture systems can be made on land which has low productivity or cannot be used for farming, such as swamps or wetlands
• Rice, chicken, pig and duck production can all be combined with aquaculture to increase productivity in all systems which are combined. These systems can also be integrated with terracing, swales and water catchments
• Aquaculture systems assist water flow and drainage during the wet season. During the dry season, these systems provide water storage which can be used for animal and crop needs
• Aquaculture systems change and modify climate, they make the temperature around
cooler and more comfortable. This is very beneficial for trees and areas surrounding the house
• Aquaculture systems will attract birds, frogs, useful insects and many other pest predators.
This will increase crop pollination, and reduce pest problems in areas around the aquaculture system.

Step by Step Aquaculture Systems
An aquaculture system, whether large or small, will be easier to make and maintain if neighbors
and the community work together. The objectives are:
• To create a pond or ponds which are productive and healthy
• To make ponds with as much edge as possible. More edge = more food for fish = bigger and healthier fish
• To produce a variety of products from the same area

AQUACULTURE SYSTEM NEEDS AQUACULTURE SYSTEM PRODUCTS
Construction materials, labour, water, water plants, trees and plants, fish, prawns, eels, fish food, oxygen in the water.
Fish, prawns, eels, vegetables (water plants), fertilizer, mulch, cool climate, pond edge products (bamboo, trees, fruit)

Location
Fishponds need a continual supply of water. Therefore, the ponds should be located near a
water source, like an irrigation channel, river, spring or house water. For river locations, be
careful not to choose a site which could flood during the wet season. Gently sloped land will make it easier to drain and clean the fishpond or to run water in and out of the pond. This is very useful if you plan to have more than one pond in one aquaculture system on your land. Flat land is also good, but it requires more work for maintenance and water supply. Steep sloped land is very difficult to use and will require a lot of maintenance. plants and animals
provide food for fish, and fishponds provide food for plants and animals turning swampy land into fishponds

Sunlight
For most areas, a little shade will be useful for smaller fishponds. Shade reduces the waters temperature, fish won’t eat much in hot water and could even die. Shade will also reduce water evaporating from the pond. Shade is not so important for large ponds, because with larger ponds the shade won’t affect the water temperature as much. Some shade can be provided by trees and water plants which cover theponds surface. Use trees that only give a little shade and can be cut back as needed, such as moringa, leucaena, guava, mulberry and bamboo. For smaller ponds, a simple shade structure made of bamboo and palm leaves will provide temporary shade until the trees grow tall.

BEWARE!
Too much shade can also cause problems, because fishponds need some direct sunlight for plant growth and to keep the system healthy. At least ½ days of sunlight is good, morning sun is best. In mountain areas, where the air is much cooler at night, the fishponds will need more sunlight to warm the water.

Size
It is better to make many small ponds than only making one or two large ponds. The ponds size should be a minimum of 3 m x 3 m or 5 m x 2 m. With this size the water will stay cool. 5 m x 5 m (25 m2) till 10 m x 10 m (100 m2) is a good size for fishponds. But remember, larger
fishponds means a lot more digging. It is better to start with a smaller pond, and if it works well, make more ponds. Smaller fishponds are easier to manage, clean and harvest. Also, if a problem affects one pond, it will only affect the number of fish in that pond. All the ponds can be harvested at different times.

Depth
A pond should have a variety of depths to function well. A shelf around the edge and a deeper
section in the middle is ideal for ponds, or it could be deep at one end and shallow on the other
end. The shallow parts of a pond provide a place for water plants, which supply food for fish
and people, homes for small fish and warmer temperatures, which encourage plankton and
pond animal growth (which are also fish food) in these areas. Some types of fish, like gurami,
need shallow areas to breed. The shallow areas of ponds should be 30-50 cm deep and 50-100
cm wide.
Two shallow areas with different depths is even better. These shallow areas create edges in the
water (more edge = more food for fish = bigger and healthier fish), and are an essential part
of any aquaculture system.
The deep areas of a pond should be around 1-2 meters deep. This will provide fish with a cool place to avoid the hot sun. The deep areas will also give the fish a place to hide from predators.

Shape
A fishpond can be made any shape you like. The more edge around fishponds will provide more areas for growing water plants and fish food in the pond, and more areas for growing plants and trees around the pond.

SMART IDEAS!
• Ponds in square and circle shapes will make digging faster, but they will provide less edge. Use simple shapes for the deep part of the pond, then make shapes with many edges for the shallow part of the pond
• When planning the shape of fishponds, always think of them as part of an aquaculture system which can be integrated with vegetables, trees and other animals

Construction
The construction of an aquaculture pond is hard work. Working together, especially when digging, will make the work much easier.
Work smart, not hard:
• Start digging in the middle where the deepest part will be. Gradually move outwards and
don’t dig too deep or too fast
• Wet the ground to make the soil easier to dig
• The dug up soil can be placed around the pond edge to raise the height of the edge, this will reduce the amount of digging needed
• Extra soil can also be used to create an extra shelf or to provide more plant production area

Clay or Cement?
Making clay fishponds is easier and cheaper, especially for areas where the soil
contains a lot of clay. To find out if your soil contains clay which is good for making ponds,
a simple test can be done by wetting a handful of clay and rolling it into the shape of a snake
which is 1 cm thick. If the clay sticks together, it means that the clay is good to use for making
ponds.
Cement can be used for smaller ponds and for where there is not good clay available
in the soil. Cement holds water much better than clay. Clay lining can also be used if there
is enough good quality clay around your area. The layer of clay or soil used for ponds should
be about 5-10 cm thick. Make sure the lining does not dry out during the dry season, because
this could cause cracking or leakage. If the pond does crack or leak, add another layer of fresh
clay or cement.

Clay Pond Techniques
Once the fishpond has been dug and shaped, layer it with clay to reduce water leakage. This
will help a lot, especially if there is limited water supply. Pack down the clay by stomping on it,
or use cows, buffalo and goats to walk over the pond until the clay had compacted.
Fresh cow and buffalo manure also helps to seal ponds. Lime powder can also be used to help seal the pond and balance the soils pH levels. Use 2-3 kg of lime powder for a pond of 100 m2
(10 m x 10 m).

Cement Pond Techniques
The amount in the cement mix used for layering ponds must be more than what is used for
making cement bricks, so that the cement is stronger. It is also important to use iron or wire
mesh as a frame to hold the cement together and prevent cracking.
A line of rocks around the top edge of the pond will strengthen the ponds edge and will also
look beautiful. Try to keep the cement moist for few days during the process of making the
pond, until the cement dries perfectly. If cracks do appear, add another layer of cement.
When the cement dries, paint it with vinegar, then fill the pond with water. Leave for 2 days,
then empty the water and repeat the process twice more. The last time you fill the pond with
water, it will be safe for fish to live in.

Pond Water
The water that flows into the fishpond must be clean to prevent the bottom of the fishpond from filling up with soil. Water from rivers can contain a lot of soil, so it must be filtered first. Too much soil can cause problems for natural food production and this fishpond will need to be cleaned more often. If water from springs or rivers are used:
• Line the water channels with rocks or cement. Plant
grasses or small plants along these channels to help stop erosion
• First run the water into a pond which is only used for growing water plants. This pond will catch soil and filter the water, so that when the water flows into the fishponds it will be much cleaner. Remove the soil which collects in the plant pond and use it to fertilize gardens
• Dig a ‘soil trap’ in the trench before the fishpond. This soil trap will clean the water by catching soil at the trenches base as the water flows through the trench. Make the hole 1 meter deep if possible. The soil that collects in the soil trap is fertile soil, and it can be used to fertilize gardens

Drainage Pipe
On sloped land, a drainage pipe can be added during construction of the pond. This drainage
pipe can be made of bamboo, plastic piping (paralon) or metal piping; whatever material is
available. Cover the end of the pipe which is in the water to prevent the pond water from
leaking. This pipe is used to drain the pond if needed. This method is much easier than
emptying the pond using buckets!
A plastic hose can also be used to drain ponds. Fill it with water, cover one end of the hose, put
the other end of the hose into the pond and the covered end outside the pond, but positioned
lower than the pond, then open the hose end. Water will suck out of the hose using gravity.
This method will only be successful on sloped land.

Water Overflow Points
An overflow point is where excess water will flow out of the pond. This point is needed to
be able to direct water to where you want it. It should be big enough to manage overflow
waters during the wet season or heavy rains. Make this point at a low point in the ponds wall.
If possible, layer this area with rocks or cement to prevent erosion. A large piece of bamboo
placed in the ponds wall will also help a lot.

Drainage pipe running water from a spring to the fishpond
Attach a piece of wire at the end of the overflow point or on every pipe used to prevent fish escaping from the pond. This will also help to keep the water clean, which is important if the overflow water runs into another pond. Try to run the overflow water to paddies, swales or other water catchments so the overflow water, which is filled with nutrients, is not wasted.

BEWARE!
Fish are very sensitive to pesticides and herbicides in water. These chemicals can make them sick or die. Don’t use pesticides or herbicides on lands above the pond location, because they will flow down into the pond. It is important to address this issue on a community level, so other farmers do not use the chemicals on their lands above you, because this will affect your aquaculture system.

Fish Production
To create a healthy, sustainable system and have good fish production, all the different parts of
a pond system must be addressed. Plants, manure, bacteria, plankton, insects, frogs, leaves,
fruit, trees, other animals and humans all play important roles in creating a healthy environment
which can produce healthy pond products. Water in a healthy fishpond will be light green in
color. This means that there is lots of plankton and other food for fish. To achieve light green colored water, a fishpond must be prepared and managed well.

Making a Fishpond
Preparing the Fishpond
Lime Powder
For new ponds made of clay, lime powder can be applied to the sides and bottom of the pond
before adding water. The lime will balance pH levels, especially acidic soils and waters, and later
on it will help keep the water clear. Lime powder will also help with potential pest and disease
problems. Usually, pH conditions are neutral to alkaline, and because of this water is clear. Also,
pest and disease problems are usually minimal at the beginning, so only small amounts of lime
are needed. Add about 2-3 kg of lime for every 100 m2 (10 m x 10 m) of pond area. This is not
essential, but it will help a lot for new ponds. Fill the ponds with water, then leave for 3 days
before adding living creatures. Lime is not needed for ponds made of cement.
plankton grows from the decomposing materials add leaves, manure and soil fish eat the plankton

Manure
A layer of manure and soil at the bottom of the pond will make the pond healthy. Fresh manure
is better to use than dry manure, because fresh manure contains more bacteria.
Use 30-50 kg of manure from cows, buffalo or horses for every 100 m2 pond, and 8-12 kg for pond of 25 m2. Chicken and duck manure is much stronger, and only 6 kg per 100 m2 or 1,5 kg per 25 m2 of pond area. If you combine these different manures together, use half of each type of manure. Spread the manure over the whole pond bottom and sides. The manure will encourage plankton growth, which is a natural source of food for fish.
Water and soil from another, already productive pond is also a good starter for new ponds, because the water and soil will add lots of plankton and bacteria. Add this soil together with
the manure.

Plant Materials
Before adding fish to a pond, add lots of leaves and plant materials to encourage bacteria and plankton growth, and to provide food for the fish. Legume trees are good to use. Use 40-50 kg of leaves and branches, tied in bundles, for a pond of 100 m2. Place these materials around the pond edges. After one week, the materials can be replaced with new materials, continue to do this until the water turns green in color. This is very important, especially for cement ponds.

Providing Shade
Shade will keep fishponds cooler, but don’t let the sun become blocked out completely because
sunlight is still needed, especially morning light. Trees and plants will provide shade long term.
If there are no trees, you can provide some shade by making a simple shade structure from
bamboo, wood or leaves, or make a structure for growing vine plants, like pumpkin, luffa,
grapes and passion fruit.

Water Plants and Small Water Animals
Water plants will provide habitat for small fish, food for the fish and their rotting leaves will help plankton and bacteria growth. Water plants can also provide food for people. Grow many different types of plants which provide different functions to keep the aquaculture system healthy.

Some different types of plants which can be grown are:
• Plants that grow from the soil: Taro, arrowroot, reeds, etc
• Plants that grow from the soil and on top of the water: Kangkung, watercress, etc
• Plants that live on top of the water: Water lilies, water hyacinth, lotus, etc
Many of these plants function as water cleaners. These plants will remove excess nutrients and
help to remove any toxins. This will help to maintain a healthy pond environment. Small water
animals can also be added, like water snails, prawns and frogs. They will reproduce naturally
and will become an additional source food for some larger fish.

Providing Homes for Fish
Small fish sometimes need protection from larger fish, because certain types of fish will eat other types of fish which are smaller. A place for fish to make their own nests
is also needed. All water creatures will be healthier if they have a good habitat. Piles of rocks, water plants, old tires or old drink cans tied together, will all provide space, homes and habitats for fish. Tilapia needs shallow water to make their nests. A shelf or shallow area, as already explained previously, will provide a nesting area for these fish.

Plants Around the Pond Edge
Plant areas around the pond edge immediately to hold the soil in place and prevent erosion.
Pond edges are very fertile, because they receive lots of water and nutrients.
Plants which can be grown along pond edges are:
• Water plants: Taro, arrowroot, kangkung and watercress will all provide food and habitat
for pond animals
• Grasses, to strengthen the pond edge
• Vegetables, small vegetable plots can be made around the pond edge
• Small fruit trees: Banana, citrus and papaya trees. Plant 1-2 meters from the pond edge. These plants like lots of nutrients and will not provide too much shade
• Large fruit trees: Mulberry and guava trees are best. Choose trees which can be cut back and will not provide too much shade. Plant 2-3 meters from the pond edge, and don’t
plant too many
• Legumes: Moringa, leucaena, and acacia will provide many functions including food for fish. These trees can also be cut back as needed

Add the Fish
There are many types of fish which can be grown, including: Carp, mujair, tilapia, catfish,
gurami, prawns and eels.

Fish Categories Based on Diet
Based on what fish eat, they can be divided into 3 categories:
1. Herbivores: Only eat plants, plankton, leaves and grains, for example carp
2. Carnivores: Only eat meat or animals, including insects, small pond animals and other
fish, for example eels and catfish
3. Omnivores: Eat everything, they eat plants and also eat meat, insects and small pond
creatures, for example tilapia, gurami, catfish, mujair and carp
There are many different types of catfish in the world, there are some that are carnivores and
others which are omnivores, but the most common type is omnivore. There are also different
types of carp, some which are herbivores and others which are omnivores.
A healthy aquaculture system can contain many different types of fish. The fish will naturally
create a balance between themselves. Different types of fish will feed on different layers in
the water and will maximise the use of food and space in the pond. These fish will also play
different roles in keeping the pond healthy.
The fish that feed at the top and middle of the pond, like tilapia fish, will eat most of the fish
food, mosquito larvae and other insects. The fish that feed at the bottom of the pond, like carp,
mujair and catfish, will eat food and plant materials that drop to the bottom of the pond and
the plankton which grows at the bottom of the pond. Larger ponds will provide enough space
to breed many different types of fish.
If you want to keep all three categories of fish, you must introduce them to the
pond in the right order:
First: Add herbivore fish
Second: Add omnivore fish when the herbivore fish are 3 months old or more
Third: Add carnivore fish 3 months later
Carnivore fish, like catfish, will eat other small fish so they must be added last. The omnivore
fish usually won’t eat the other small fish.
Once the fishpond is established, it will manage itself. However, some additional food and
general maintenance is still needed. Continuously observe the health of the fish and number
of each different type of fish.
The carnivore fish will control the number of small fish by eating them. This will help to prevent
overstocking the pond with fish. Some protection in the pond like rocks, water plants and old
drink cans, will provide the smaller fish with a place to hide so some of them will still survive.

Fish Stocking Rates
3 fish per 1 m2 is good for most fishponds. For 100 m2 of pond, there should be about 300 fish.
This number is good for healthy fishponds. The number of fish can be increased to 5 fish per
1 m2 of pond if extra food is added and the pond is managed well.
The following example of stocking rates can be used as a general guide:
About 30% (90) : Tilapia, gurami
About 50% (150) : Carp, mujair
About 20% (60) : Catfish
Raising eels together with fish can create problems, especially in smaller ponds. The eels will
reduce the number of other fish. Sometimes they will naturally enter fishponds from rivers or
paddies.
Always try to keep their numbers low, and only introduce them if you are confident you can
manage them well. However, it is still better to raise eels separately.

Types of Fish
Carp
Carp are common in many areas, they are tough and usually disease resistant.
• Food: Carp are usually herbivores, which only eat vegetation and
plankton. They will feed at the bottom of the pond. Carp food can be provided by adding
animal manure, rice husks, leaves, fruits and other rotted natural materials
• Growth: Carp can grow up a weight of ½ kg in 6 months in good conditions and with
enough food. They can grow to 2 kg or more if desired, but the meat is tastier when the
carp are still young
• Breeding: Carp will lay eggs after 8-12 months. The female carp lay eggs all year long
and will place the eggs around pond vegetation. The eggs will hatch in 2-6 days, and the
baby fish will start eating when they are 2 days old
• Stocking rates: In a fishpond of 100 m2 (10 m x 10 m) you can stock around 150-300
fish. In a fishpond of 25 m2 (5 m x 5 m) you can stock around 40-75 fish (around 2-3 fish
per 1 m2). The number of fish depends on the amount of food supply in the pond. If too
many fish are kept in a pond, they will grow slowly and not reach their full size, and will be
more likely to become sick

Tilapia
Tilapia is a very important fish because they are easy to feed and they will eat mosquito larvae that breed in fishponds.
• Food: Tilapia eat plankton, water plants and insects. They will grow well in natural, healthy fishponds and all the food they need is already provided. With extra feed, like rice bran, crushed corn, cassava and so on, they will grow much faster and will breed more quickly
• Growth: This fish can grow to a weight of 200 grams in 6 months with good food supply
• Breeding: Tilapia reach sexual maturity after 6 months and they can breed 6-8 times in
one year. They will breed naturally in healthy fishponds, in shallow parts or shelves of the
pond. Remove the baby fish as soon as they come to the ponds surface and keep them
separate by using nets or cages. This will make it easier to sell young fish, and reduce overstocking problems
• Stocking rates: The ideal rate is 3 fish per 1 m2 of pond. Because this fish breeds so often, overstocking problems can occur. Too many fish will cause the fish to grow smaller. This problem can be prevented by moving the baby fish as soon as they come to the ponds surface or by adding some catfish to the pond when the talipia are starting to breed. The catfish will feed on the small talipia and keep their numbers low.

Catfish
Catfish taste good and are disease resistant.
• Food: The type of catfish most commonly raised are omnivore.
Almost all food needed for this type of fish is naturally available in healthy ponds. Extra
feed can be added, such as meat or food scraps
• Growth: Catfish can be eaten between the age of 6-18 months
• Breeding: Catfish carry their eggs in their mouth until the eggs hatch. They will produce many young if their eggs hatch. However, catfish are difficult to breed so to increase their numbers you can collect more fish from rivers or paddies
• Stocking rates: These fish can be kept at a rate of 1-2 fish per 1 m2 of pond. If you want to stock more than this number, extra feed must be provided

Gurami
Gurami prefer ponds with lots of water plants. Therefore, they are
good for raising with water vegetables or rice production.
• Food: Gurami are omnivores and will eat water plants, insects, plankton and fruit
• Growth: They can grow to a weight of 80-120 grams in 6 months
• Breeding: This fish will breed naturally, but the survival rate of the baby fish is very low
• Stocking rates: The stocking rates for this fish is around 5-10 fish per 1 m2 of pond, if
enough food is available

Mujair
Mujair have similar behavior traits as carp.
• Food: Use same food as for carp
• Growth: They will grow to a good eating size in 4-6 months
• Breeding: Mujair fish breed easily, and can breed 2-3 times a year
• Stocking rates: Mujair are smaller than carp so the stocking rates can be slightly higher, about 2-4 fish per 1 m2 of pond, or 200-400 fish per 100 m2.

Freshwater Prawns
In many areas, freshwater prawns grow naturally in rivers and ponds. They are very difficult to raise from eggs or young. Therefore, you can catch them in rivers and transfer the smaller prawns to ponds. The best time is when the young prawns have shed their first skin and have just started growing their adult skin. Before this time, they need special attention, different water temperatures and specific foods. The benefit of growing prawns in a pond is that they will grow much larger than they do in the wild. The prawns can survive in smaller sized ponds. Prawns like ponds with lots of fresh water or if possible running water.

Eels
Eels live in rivers and paddy areas. They can cause problems with stocks of other fish because eels like to eat small fish. However, if eels are introduced in small numbers when the fish are already large enough, they can be combined. Only experienced fish farmers should experiment. Because eels are carnivores, their feed can be very expensive. The following example is one method for raising eels. This method works well for ponds of 15 m2 (3 m x 5 m). First, add a layer of mud an manure to the bottom of the pond. Then, add a layer of cut banana stems, add another layer of leaves and grass. Repeat this process until the pond is full of these materials. Fill the pond with water, and wait until the materials become rotten, usually around 1-2 months. After this, the eels can be introduced into the pond, use 100-150 eels. The rotting materials will provide food and habitat for insects and small water animals, which will then become food for the eels. Extra food can also be added to increase eel production, this could be animal intestines, blood, bones, skin, kitchen scraps, frogs, dead rats, termites and so on.

Breeding Fish
Proper breeding techniques for freshwater fish is very technical and often difficult. Some types of fish, like tilapia, will breed naturally, but other types of fish need special techniques, conditions and specific tools. The methods used for fish breeding are too long to include in
this manual. However, for those who plan to breed fish or are interested, you should look for more information.
Some benefits of breeding fish:
• Provide continuous supply of young fish
• Improve production and quality
• Produce young fish to sell
To hold young fish, make a basket or container of bamboo to use inside the pond.

Water Plant Production
There are many different types of water plants which can be grown for food or to sell. Taro,
kangkung, watercress, arrowroot and lotus are some water plants which are commonly grown.
The leaves, roots and young seeds of lotus plants can be eaten and taste good. Plant growth
will be faster if you add a small amount of manure to the pond. All water plants need fresh
water added to the pond often to be able to grow well. Fish and water plants that produce food
can easily be grown together. The plants and fish will help each other because the fish manure
will become plant food and the plants will provide rotten leaves and habitat for the fish.
house for young fish

BEWARE!
All water plants should be harvested regularly and controlled so they do not grow over the entire pond surface. Kangkung and watercress grow very quickly, which can cause problems for fish because they will take too much sunlight and oxygen. The water plants should at the very most cover ¼ of the pond surface. Plants which cannot be eaten or sold can be used as mulch or compost.

Fish Food
Herbivore and omnivore fish include carp, tilapia, gurami, mujair and catfish.
To provide continuous food supply for fish and to keep the pond environment healthy, continue
to add manure and leaves to the pond. One week after fish have been introduced into the
pond, begin adding manure. Use 30-40 kg of manure per 100 m2 of pond every week, or 8-10
kg per 25 m2. For old fish ponds that already are light green in color, the amount of manure
can be reduced to 20 kg per 100 m2 of pond every week. The amount of manure used depends
on the color of the pond water.
The color of pond water is very important because it shows how much fish food is available in
the pond. A good way to test this is by placing your hand 10-20 cm into the water. If you can
still see your hand, it means the water is too clear.
• If the water is too clear, the amount of manure added should be increased until the water
becomes light green in color
• If the water is light green in color, the amount of manure added can stay the same
• If the water is too dark, the amount of manure added should be reduced until the water
becomes light green again.
Another sign of too much fertilizer is if the fish are always at the waters surface until late afternoon and are acting strange. Also, if the fish do not move when scared. If this happens, stop adding manure and add more water to the pond. Sometimes, add a small amount of leaves and rotten fruit. If there are water plants growing, you do not need to add more leaves.

Other factors which can affect the color of pond water are:
• Too much sunlight can make the water color too dark
• Too much shade can make the water color too clear
• Not enough fresh water can make the water color too dark
Using the right amount of manure and leaves will keep your pond healthy. A healthy pond will
provide enough food for the fish to grow well and healthy. When the pond is harvested, the
manure can be reused as fertilizer for crops. Pond systems made of cement or large scale fish
production systems are the most likely to require extra feed for fish.

Extra Feed
Extra feed will help the fish to grow faster and allow you to increase the number of fish in a
pond. To achieve maximum benefits, the fish food should contain protein, fat, carbohydrates,
energy, minerals and vitamins. Feed the fish twice a day, at the same time each day. Increase
the amount of feed given as the fish grow larger. A good amount of fish food will be all eaten in
10 minutes. If the food is eaten in less time, add a little more. If more than approximately 10%
is not eaten, reduce the amount. Too much feed will cause problems by reducing the amount
of oxygen in the pond and by building up at the bottom of the pond.

Extra Feed for Omnivore & Herbivore Fish
Types of natural feed that we can produce ourselves include:
• Grains, contain protein, carbohydrates and fat, for example rice bran, broken rice, crushed corn, millet
• Legumes, their leaves and seeds contain lots of protein and minerals, for example beans, moringa, peanuts. Legume seeds should be cooked first, before feeding to fish
• Fruits and leaves, contain a range of vitamins, minerals, carbohydrates and protein in small amounts
• Roots, contain carbohydrates and energy, for example cassava, taro, sweet potatoes, potatoes. Root vegetables should be cooked first, before feeding to fish, and only a small amount is needed
• Meat and animal remains, contain protein, minerals, vitamins and more, for example animal intestines, blood, bones, feathers, kitchen scraps, frogs, mice, termites. All meat, except for dead mice, frogs or termites, should be cooked first to reduce chances of spreading disease and worms
• Oil seeds, contain protein, oil and low amounts of carbohydrates, for example soybeans, sunflower, kapok seeds, candlenut, coconut and peanuts
• Kitchen scraps, which contain all of the nutrients above, are a great source of fish food Carp, tilapia, mujair and gurami only require a small amount of meat or none at all. Catfish will grow better if you add some meat to their food.

Extra Feed for Carnivore Fish
Eels are carnivores, catfish are omnivores, but they eat a lot more meat than other types of
omnivore fish. They will eat small fish, frogs, worms, insects, prawns, snails and other water
animals. Meat and other animal remains, prepared in the same way as for omnivore fish, are
good for these types of carnivore fish.

Processed Feed for All Types of Fish
What is meant by processed feed is feed which can be bought in stores, which is made in factories. Almost all ponds do not need processed feed, but for some situations processed feed is a good way of making sure that fish are getting enough nutrients.
Some situations like this could be:
• Large scale fishpond production
• Cooperations of fish farmers, who can make the feed in groups and then divide it between the group members. Processed feed takes time and money to make, so it should be produced in large scale quantities. If you are interested in producing processed feed, you can learn more details from other information sources and books.

Fish Diseases and Pests
Diseases
Diseases which are most commonly experienced by fish are parasites and worms. Some symptoms of these are:
• Fish trying to scratch their own bodies on rocks and are moving slowly
• The fish have swollen, fat bodies (They are actually very thin, but their
stomachs are filled with worms)
One way of handling these problems is by using salt, The salt will also help to clean fish gills
and treat bacterial ulcers. If only a few fish are diseased, treat them using salt and water in
buckets. Always use water from the fishpond and kitchen salt. Method:
1. Dissolve the salt in water, use 25 g of salt per liter of water for a 30 second treatment, or
10 g of salt per liter of water for 30-60 minutes of treatment
2. Stir the water to add oxygen
3. Place the fish into the bucket. Observe the fish carefully, if they show any signs of stress, move them immediately to fresh water
4. Repeat this method 2 times in a row, afterwards the fish can be returned to the pond
This can be used as a quarantine method of killing diseases before adding new fish to a pond.
If many fish are diseased, then you can treat the whole pond. Use 1.5 kg of salt per 1 m3 of
pond water, for example a pond of 10 m x 10 m (if the pond is 1 m deep, it has 100 m3 of pond
water, if the pond is 2 m deep, it has 150 m3 of pond water), uses 150 kg of salt for 100 m3 or
225 kg of salt for 150 m3. Always dissolve the salt before adding it to the pond. After one day,
continue to add fresh water as usual. Observe for signs of stress in water plants, if they seem
stressed, add more fresh water. Formalin can also be used. Add 2 ml of formalin to 10 liters of
water. Put the diseased fish into this solution and leave them for 15 minutes, after this return
them to the fishpond.
To prevent worm disease problems, add some lime powder to the empty pond as the pond is
being built, this will help a lot. Adding lots of fresh water to fishpond will also help to prevent
all types of disease. After any disease treatments, change the pond water if possible to prevent
the same disease from spreading again. Also, try to add more oxygen to the fishpond.

Pests
The main fish pests are birds and humans. Snakes and crabs can sometimes cause small problems. These pests will always be around the pond. By killing off any of theses pests, you
will damage part of a healthy ecosystem, because these pests have important roles in the overall ecosystem of the garden, for example birds eat many insect pests which damage crops. The best way to manage pest problems in the pond is by prevention and always thinking of different ways to minimize potential losses and damage to the ecosystem.

Ways to prevent bird pest problems:
• Provide a place in the water where fish will be protected, for example rocks, water plants, old tyres and tin cans
• Cover the pond surface with palm leaves to stop birds from diving into the pond
• Provide a deep area in the pond, so fish can escape there
Ways to prevent attacks from human pests is only by reducing jealousy and increasing working together within groups and communities.

Oxygen
Oxygen is essential for a healthy pond and it is in every drop of water.
Oxygen is needed by all the living creatures in the pond. There is less oxygen in water which is warm and still. A lack of oxygen could be caused by:
• Overstocking, too many fish
• A lack of fresh water
• Giving too much feed • Adding too much manure
• A lack of sunlight, which is caused by too much shade and water plants
Signs of too little oxygen could be the fish are at the water surface from early in the morning and are always opening and closing their mouths, and they do not respond to surprise.

Oxygen can be replaced and increased by:
• Flowing water into the pond. If there is a continual supply of water, than only a small amount of water needs to be run into the pond
• Adding fresh water regularly, every few days, especially for small ponds
• Increasing the pond depth. A deep pond will stay cooler than a shallow pond. Cool water
holds more oxygen than warm water
• Moving the water. Moving water will return oxygen to the water. Move the water as often
as possible, by using the wind, water pumps, windmills or by simply stirring the water

Cleaning the Pond
The best time to clean the pond is after harvesting fish. If there are fish still being kept in the pond, move the fish to a container and return them to the pond after it has been cleaned. Leave a very thin layer of soil or manure at the bottom of the pond so good bacteria stays there. Don’t forget to use the pond bottom soil to fertilize your garden.

Potential Problems
Pollution
Pollution can cause big problems for fishponds. Pollution can come from chemicals, oil, petrol and even soap water. Water from the kitchen and washing water contains detergents, and this water cannot be run directly into fishponds. This water must be cleaned first by running it into a separate pond used to filter the water, after this process it can be run into the fishpond. Grow water plants, like reeds, lotus and water hyacinth, in the water filter pond. Don’t use plants which will be eaten. These plants, besides functioning to filter the water, can also be used for mulch. (For more information about how to clean water, see – Houses, Water and Waste Management). Using pesticides and herbicides is also dangerous. To reduce potential pollution problems, don’t use pesticides and herbicides on land above the pond area, because they flow down into the pond. Water pollution could come from sources far away, especially if you are using water from rivers. Work together with you community to reduce using chemical products which could pollute irrigation water. Working together will benefit everyone involved.

Over Feeding
Over feeding can cause problems to do with water quality and the amount of oxygen available
in the water. Water piling up at the bottom of the pond will also make the pond more shallow
quickly. If these problems do occur, the quickest solution is to change the pond water.

Mosquitoes
Mosquitoes can carry many dangerous diseases, such as malaria and dengue fever. Mosquitoes
lay their eggs in ponds, and the mosquito larvae will stay there until they are ready to fly.
Some types of fish, like tilapia, will eat mosquito eggs and larvae, frogs will also help with this.
Neem leaves can be added to the fishpond to stop mosquito problems. Add neem leaves to the
pond regularly, or spray a liquid solution of 3-4 ml neem oil and 1 liter of water over the pond
surface. Neem will stop mosquitoes from breeding without harming the fish. Be careful using
other types of natural pesticides, because they could be harmful to fish.

Other Types of Fishponds
Wet Season Fishponds
If during the dry season there is limited water supply or no water at all, a pond can be made for
use only during the wet season. Trenches, swales and good irrigation can be used to increase
water supply. Soil traps to filter water can be made if swales or trenches are used, or if the
water comes from rivers. The amount of oxygen in the water will be reduced if the water supply
is not regular.

SMART IDEAS!
• To grow fish to their maximal size, raise them in a separate container or water tank for 1-2 months, then move them into the pond at the beginning of the wet season
• During the dry season, when the pond is not being used, the bottom of the pond can be used for growing vegetables
• If the pond is not used for growing vegetables, cover it with a temporary shade structure to prevent cracking (including ponds made of cement)

Saltwater Fishponds
For areas close to the sea, a saltwater fishpond can be made. The pond is made by simply
digging a hole near the sea, which will then naturally fill with saltwater. The location of the
pond should not be much higher than sea level, because if it is too high it will be difficult to
reach the water. The best areas are where water plants are already growing (swampy areas).
By creating a fishpond, you will create a productive area on unproductive land which is not
being used for anything. However, be careful not to change the natural environment too much
or damage the surrounding area, because these areas are very important for keeping the coast
and sea healthy. Create an area as natural as possible by using local plants. The most common
fish raised in saltwater ponds is the milkfish.

Constructing and maintaining saltwater fishponds:
• Use the same guidelines for the pond size and shape as used for making fresh water ponds
• The pond water level will rise and fall as the seawater rises and falls, so the pond must be made deep enough to still contain enough water during very low tides
• Rocks and plants around the pond edges are important to protect the pond and prevent erosion, especially if the soil contains a lot of sand
• The most common pests in coastal areas are birds, like seagulls, so some form of protection against birds must be provided
• Some shade is essential to keep the pond water cool. Water plants will help, and they will also provide food for fish
• Special consideration must be given in areas where crocodiles may come. Strong fences must be built around the fishpond to protect the fish (and you!) from crocodile attacks

Integrating Fish with Other Systems
There are many systems which can be integrated with fish, like chickens, pigs, ducks, vegetables,
paddies and more. Following are some examples of techniques which can be used, but you can
use these techniques with any of your own ideas that you think will work well.

Fish with Chickens
The number of chickens kept will depend on the size of the fishpond and the number of fish, for example:
• A pond of 25 m2 (5 m x 5 m) : 5 chickens
• A pond of 100 m2 (10 m x 10 m) : 5-10 chickens
• A pond of 1000 m2 (20 m x 50 m) : 30-50 chickens
The chicken coop can be built over the fishpond, this will provide many benefits, the chicken
coop will provide shade and when it is cleaned out, left over chicken feed will fall into the fishpond and become fish feed. Plan where the chicken coop will go before building the pond, especially if the pond will be made of cement. The chicken coop should provide protection against wind and rain, but still have good ventilation, and the floor of the chicken coop should be strong enough to hold the weight of a person when cleaning the chicken coop.
Leave the chickens in their coop until midday so that they will lay eggs inside the coop. After,
let the chickens out to search for food on their own. Provide some feed for the chickens during
afternoon to attract them back into their coop. If the chickens are kept in the coop all day,
they should be fed twice a day, chicken feed can be grains, corn, beans, some fresh leaves and
weeds. Don’t forget to provide fresh water for the chickens to drink. Chicken manure which falls
into the fishpond will provide the fish with additional nutrients. However, fresh water must be
added once a week to keep the pond water fresh. The pond should be cleaned out completely
every one or two years.

Fish and Rice Paddy Systems (Mina Padi)
There are some types of fish, like catfish and eels, which naturally live in paddies. However,
other types fish, like tilapia, gurami and carp can also be raised in paddies, so long as there
is enough water and the paddies are free of pesticides. If the paddies used are close to the house, this is much better because they will be easier to manage. Small fish should be raised in separate ponds and added to the paddies after the rice is already growing. This will prevent the fish from eating the young rice plants. A separate, deeper pond can be made connected to the rice paddies. When harvest time is close, the water will dry up and become warmer, and the fish will then naturally escape to this separate pond. This pond should be made in area lower than the paddies. This system can be managed the same as a normal fishpond. Water flow and fish population can be controlled by using trenches and doors.

Some benefits of using this system:
• There will be two different products from the rice paddies, fish and rice
• Some fish, like tilapia and gurami, will eat mosquito larvae and reduce mosquito problems in the paddies, they will also feed on insect pests which damage rice crops
• Fish manure will fertilize the rice paddies
• Rotten vegetation from the rice crops will become food for fish.
Small ponds for young fish can be made next to the irrigation trenches which flow into the rice paddies.

BEWARE!
If you use pesticides and herbicides you will kill the fish. Even some natural pesticides,
like tuha and tobacco, are too strong and dangerous (tuha is actually used as a fish poison). Use Integrated Pest Management (ITP) techniques for managing rice crops and be careful with natural pesticides. (For more information about ITP, see Integrated Pest Management).

Fish with Ducks
Integrating fish and duck production requires a large pond and careful maintenance. However, there are some simple integration methods that will still provide benefits. Make a small separate pond for ducks, but higher than the fishpond. Water that flows from the duck pond into the fishpond contains lots of duck manure, which will provide food for fish. The ducks must be kept away from the fishpond, because they can damage the pond edges and eat small fish and water plants. To prevent this from happening:
• Build a low fence around the duck pond and duck area, or around the fishpond
• For small fishpond, you can make a lattice cover out of bamboo. Make sure enough light
can still pass through. This cover will also protect the fish from other birds. The ducks will need a house, food and fresh water, just like chickens. They can be left out during the day and returned to the house at sunset to eat and sleep.

Growing Vegetables During the Dry Season
Clay fishponds can be used for growing vegetables during the dry season, when the fishpond is not being used for fish production. The soil at the bottom of fishponds is very nutrient rich because of the manure and leaves added to the fishpond during fish production. The manure and leaves will create mud. Plant fast growing vegetables that can be harvested in one season. Be careful not to damage or dig through the bottom of the pond or the clay layer beneath the mud, this will create leakage in the pond. Grow vegetables that do not need any pesticides, because pesticides will damage the pond ecosystem when the pond is again used for fish production.

Fish with Swales
Swales catch and store rain water. During heavy rainfalls, water will flow from one swale to the
next, and it can be directed into fishponds. Swales can also be used to direct overflow water from
fishponds. There are also other types of water catchments that can be used for this same purpose, like compost pits and terraces.

a sloped land chinampa
Chinampas
Chinampa is a term for a water trench system from Mexico. This system can be used where there is a good source of water and where the soil is able to hold water. Clay soils are the best soils for this system. If there is a continual water source, chinampas can be used all year round.
Chinampas can be used both on sloped lands and on flat lands. Chinampas can be used to
grow fish and water plants. The land around a chinampa will become very productive and can
be used to grow vegetables, fruits, bamboo and more.

Sloped Land Chinampas
Chinampas can be used to grow fish and water vegetables on land which is too steep for large
fishponds. However, on land with very steep slopes it will be very difficult to build and manage
a chinampa system. The best land to use is land which is sloped but not steep. On sloped
land, chinampas are made similar to swales with trenches dug on contour, but the trenches for
chinampas are wider and deeper than the ones used for swale systems.
The trenches should be 1-2 meters wide and 1-2 meter deep in the middle of the trench. The size
depends on the slope of the land (smaller chinampas for steeper sloped land), the amount of land
and what you plan to grow. Fish need wider and deeper chinampas than water vegetables.
Small plots can be made for planting vegetables. The trenches are closer together as well, about 3-4 meter between each trench. Water will flow from trench to trench through pipes or simple trenches lined with rock. The soil between trenches will stay moist and is ideal for growing vegetables and fruit trees. Vine plants can be grown over the trenches to provide some shade.

Flat Land Chinampas
Chinampas on flat land can be made larger than chinampas on sloped land. However, make the
size suitable for your needs. Chinampas are very good for changing flat land that is continually
wet, like swamps, into highly productive land. Water runs through the trenches, and so kangkung can be grown there. On flat lands, chinampas do not need to be on contour (because there is no land contour, the land is flat) and pipes are not needed to direct overflow water. The trenches can all be connected or a flat land chinampa overflow trenches can be used.

Drying and Storing Fish
During harvest time, there will be large quantities of fish, too much fish to finish by eating and
selling. To reduce wasting fish, it is important to know ways of preserving and storing fish for
longer periods of time. Using a solar drier is a good and inexpensive way to dry fish, and it will protect the fish from insects and animals. (Fore more information about how to use solar driers, see Module 12 – Appropriate Technology). Store the dry fish in a cool, dry and protected place.
The best aquaculture system that you can create is one that suits your own needs. Every aquaculture system will be different because the land is different, the people are different and their needs are different. Use the techniques and ideas that you like and develop them with your own ideas.

Lintah/Leech

2009-02-19T21:15:00.002+08:00

Lintah Dalam Perubatan
Lintah adalah spesis cacing (annalida) yang telah banyak digunakan dalam bidang perubatan terutama dalam menyelesaikan masalah pengaliran darah, sejak zaman dahulu lagi. Kandungan hirudin yang ada di dalam lintah adalah bahan yang sangat berkesan untuk menahan darah dari
membeku manakala Histamin pada lintah pula dapat mengembangkan salur kapilari darah.
Saintis-saintis telah membuktikan bahawa :
“Extracts from the salivary glands of sanguivorous species of Euhirudinea used for medicinal purposes” “The benefit of using medicinal leeches, or Hirudo medicinals were first recorded by Themison Laodicea in 50 BC”. “Napolean’s military surgeon, Franccois-Joseph-Victor- Broussais, have use leeches for the medical benefits on 1833.” “In 18th century, Europe had used leeches to suck their tocsid blood”

Dalam bidang perubatan, air liur lintah / ekstrak – mengandungi bahan bius, bahan anti pembekuan dan bahan antibiotik yang berkesan. Ia juga menghasilkan bakteria (aeromonan hydrophila) untuk mencerna darah dan menghasilkan antibiotik untuk membunuh bakteria lain yang mungkin menyebabkan pembekuan. Terapi lintah (bekam) juga turut digunakan untuk memulihkan pengaliran darah selepas menjalani pembedahan kosmetik Kelebihan terapi lintah –
jerawat, migrain, menormalkan serta membaik pulih kapilari darah, kesan anti-inflamasi yang cepat serta melegakan tekanan. Di Malaysia, terdapat dua jenis lintah yang diternak secara komersil oleh individu persendirian atau berkelompok iaitu lintah daripada jenis perut hijau dan lintah perut perang. Di atas harga pasaran lintah yang stabil iaitu purata RM60 sekilogram dan pemintaan untuk dijadikan bahan kecantikan dan juga digunakan di dalam perubatan, maka
dengan tidak secara langsung menggalakankan lagi industri Lintah di Malaysia hari ini.

Penternakan lintah secara komersil mula timbul di negara ini sejak dua tahun lepas berikutan wujud permintaan terhadap haiwan itu apabila beberapa syarikat mengusahakan perniagaan perubatan berasaskan lintah.Sebelum ini, permintaan terhadap lintah adalah kecil walaupun
bidang perubatan berasaskan lintah telah wujud sejak 3 tahun lepas apabila pengamal perubatan tradisional menggunakan haiwan itu bagi rawatan berkaitan kesihatan seksual lelaki di kaki lima kedai atau mengunakan minyak lintah untuk menumbuhkan ramput. Lintah telah lama digunakan dalam rawatan kesihatan di negara ini yang menyaksikan Lintah diadun dengan santan kelapa bagi mendapatkan minyaknya yang digunakan untuk kesihatan seksual lelaki selain membaik pulih tisu dan memperkuatkan otot. “Penternakan lintah ada potensi yang baik cuma tidak dieksploitasi memandangkan harga pasaran pun baik dan penternakannya mudah
dikendalikan”.
Lintah-lintah di negara-negara Barat seperti Britain, Jerman dan Rusia di mana lintah dipelihara untuk tujuan khusus, hasil penyelidikan yang lama telah membolehkan lintah digunakan dalam perubatan moden dan berjaya menghasilkan produk siap. Lintah juga turut diternakkan untuk tujuan perubatan terutama bagi masalah kesihatan berkaitan bahagian yang sensitif seperti bahagian kepala, belakang mata atau telinga yang memerlukan pembedahan, lintah hidup digunakan untuk menghisap darah pesakit dan kemudiannya darah itu dikeluarkan untuk dianalisis mengenai penyakit yang mungkin dihidapi oleh pesakit itu.Khasiat kesihatan dalam lintah terdapat pada apa yang dipanggil “Hirudin”, sejenis protein yang berfungsi menghalang pembekuan darah, yang terdapat dalam air liur lintah. Penternakan lintah amat mudah dikendalikan dengan jagaan minimum sama ada di luar bangunan (kolam konkrit atau kolam tanah) atau dalam bangunan (tangki gelas serat, tangki akuarium atau tangki lain yang sesuai) yang didapati lebih mudah.Makanannya adalah belut and keli, tetapi ada juga penternak lintah mengunakan baja lintah sebagai gantiannya, biasa ia diberikan setiap seminggu atau setiap dua minggu dan biasanya ia cepat membiak melalui sumber makanan ini. Lintah yang hidup dan diternak di Malaysia tidak sama dengan yang terdapat di negara Barat dan setakat ini menunjukkan terdapat enam jenis lintah di Malaysia. Anak lintah atau benih lintah yang boleh dijual biasanya berumur dua hingga tiga bulan manakala lintah induk pula enam bulan ke atas.Gandungan yang terdapat dalam lintah boleh digunakan untuk mengeluarkan produk kosmetik dan industri ini wujud antaranya di negara Taiwan,China, Thailand,jepun dan Korea Selatan.

Fakta Lintah

1. terdapat 650 spesis lintah
2. lintah terbesar dijumpai berukuran 18 inci
3. kira-kira 1/5 dari sepsis lintah hidup dilaut yang mana memakan ikan
4. lintah mempunyai 32 otak iaitu 31 lebih dari manusia
5. lintah Hirudo mengeluarkan anak dalam kokun dimana lintah itu membawa anak-anaknya diatas perut sendiri. Kadangkala mencapai sebanyak 300 ekor
6. tidak semua lintah adalah penghisap darah.kebanyakkannya adalah pemburu yang memakan cacing tanah dan lain-lain.
7. Lintah Amazon menggunakan kaedah yang berlainan untuk menghisap darah. Ia memasukkan proboscic panjang ke dalam mangsa tanpa menggigitnya
8. Gigitan lintah tidak menyakitkan kerana mempunyai bahan bius
9. Lintah Hirido menyuntik anti pembekuan serum ke dalam mangsanya untuk mengelakkan pembekuan darah
10. Lintah akan mengembang sendiri sehingga kenyang dan jatuh dari mangsa dengan sendiri
11. Lintah akan memgembang sendiri sehingga 5 kali berat badannya
12. Lintah pertama yang digunakan dalam perubatankira-kira pada 1000 sebelum masihi. Kemungkinan ketika India purba
13. Pada masa lampau, orang ramai akan berdiri di tepi tasik dan kolam, bila lintah melekat pada kaki mereka, ia dimasukkan dalam bakul untuk dijual. Pada masa kini, lintah Hirudo merupakan spesis terancam
14. Pakar bedah yang asal adalah seorang tukang dan mereka menggunakan lintah untuk memulihkan apa sahaja penyakit bermula dari sakit kepala ke penyakit gaut
15. Sistem saraf lintah mempunyai banyak persamaan dengan sistem saraf manusia
16. Saudara terdekat lintah adalah cacing tanah
17. Lintah boleh menggigit walaupun pada paha badak air yang tebal

INFO Lintah

* Lintah banyak digunakan untuk ramuan kosmetik dan industri perubatan.
* Lintah liar semakin sukar ditemui di sungai kerana banyak bahan kimia terenap manakala di sawah padi, penggunaan mesin bajak menggantikan kerbau menyebabkan habitatnya semakin pupus.
* Bekalan lintah semakin berkurangan menyebabkan harganya melambung sehingga mencecah RM120 sekilogram.
* Untuk 100 kilogram lintah yang diternak, ia memerlukan 30 hingga 40 kg belut.
* Lintah juga boleh mendapatkan sumber pemakanan daripada anak katak, larva terampai dalam air serta spesis umbut daun tertentu.
* Lintah boleh membesar enam hingga 10 kali ganda saiz asalnya.
* Induk lintah boleh menghasilkan 300 hingga 500 benih lintah sekali bertelur.
* Lintah adalah hermapordit (jantan dan betina dalam satu badan), tetapi perlu mengawan untuk membiak. Kedua-dua lintah akan menyalurkan sperma ke badan pasangan.
* Lintah akan melepaskan gigitan selepas darah yang dihisap mencukupi.
* Lintah boleh menghisap darah lima kali melebihi berat badannya.

MODUL DAN PANDUAN MENTERNAK LINTAH

Biologi
Terdapat lebih kurang 650 jenis lintah di dunia. Di Malaysia sahaja terdapat 6 jenis
spesis lintah yang dapat dikenalpasti.
Spesis Hirudo Medicinalis dan Hirudinaria Manillensis atau lebih dikenali dengan ‘lintah hijau’ dan ‘lintah coklat’ sangat popular untuk diternak untuk tujuan perubatan.
Di Eropah, selain 2 spesis popular yang popular tadi, lintah Amazon; Haementeria Ghilianii juga diternak.

Struktur Binaan dan Anatomi Lintah

Struktur binaan dan bahagian dalaman lintah terdiri daripada 3 lapisan otot yang kuat:-
1. Otot circular
2. Otot diagonal
3. Otot longitudinal

Lintah mempunyai badan berbentuk tiub yang fleksibel (boleh memanjang dan
membesar) serta bersegmen.
Lintah mempunyai hos penyedut (sucker) di kedua-dua hujung badannya tetapi cuma
satu hos penyedut yang terletak di kepala yang mempunyai keupayaan menyedut darah.
Lintah dari keluarga Hirudo mempunyai 3 rahang di mana setiap rahang mempunyai
100 barang gigi yang jumlah keseluruhannya seekor lintah mempunyai 300 batang gigi.
Rasa kurang sakit semasa digigit lintah adalah disebabkan oleh anesthetic atau bius
yang dihasilkan sendiri oleh lintah.

Lintah memasukkan serum anti-coagulant yang bertindak menghalang darah daripada membeku dan tersumbat. Lintah akan menyedut darah sehingga 5 kali saiz dan beratnya dan akan melepaskan gigitan selepas ia kenyang. Selepas lintah tadi melepaskan gigitan, luka tadi akan berdarah selama beberapa jam dan boleh sehingga 10 jam.

Lintah mempunyai 32 otak iaitu lebih 31 daripada manusia.
Lintah mempunyai sensor yang terletak dikepala dan badannya yang berupaya mengesan cahaya, suhu dan gegaran.
Lintah matang dan boleh dituai pada umur 6 bulan dan ke atas.
Lintah boleh mencapai umur sehingga dua (2) tahun dan mempunyai kebarangkalian
mati awal akibat sakit disebabkan habitat tidak sesuai atau lain-lain punca.
Lintah sangat sensitif dengan bahan kimia.

Habitat

1/5 daripada spesis lintah hidup di laut dan sumber makanannya adalah ikan. Baki 4/5 spesis lintah hidup di air tawar. Kedalaman air 1 kaki hingga 2 kaki sudah memadai untuk lintah.
Lintah tidak hidup di air berarus, tercemar dam masam. Tahap pH air sesuai untuk lintah ialah 7.0 ke atas (bersifat alkali). Sumber fakta dari Biopharm Leeches UK “Alkalinity is a requirement for leech survival with pH levels above 7.0 desired” Suhu yang sesuai ialah 15oc hingga 27oc. Lintah sangat sensitif dengan bahan kimia terutamanya kandungan zink yang tinggi
dalam air (Ginsberg, D., 1998). Sebaiknya ada bangsal yang dilitupi jaring hitam orked yang 50% atau 70% halang ketelusan cahaya. Cahaya sekurang-kurangnya 30% itu bagi membolehkan tumbuhan akuatik hidup.

Pernafasan

Sistem pernafasan lintah berlaku di seluruh permukaan badan badannya. Wujud pergerakan kecil di badan lintah semasa proses pertukaran gas berlaku. Lintah akuatik lebih cenderung untuk naik ke permukaan air jika mereka dapati air habitatnya kekurangan oksigen.

Organ sensor (pengesan)

Organ sensor atau pengesan lintah yang terdapat di kepala dan permukaan badan membolehkan lintah mengesan kehadiran cahaya, suhu dan gegaran atau pergerakan. Reseptor kimia di kepala lintah juga memberi keupayaan kepada lintah untuk menghidu bau dan juga bertindak sebagai mata memandangkan lintah adalah buta.

Pembiakan

Lintah adalah hidupan hermaphrodites iaitu mempunyai dua jantina dan dua organ
pembiakan jantan dan betina. Lintah mempunyai clitellum, satu kawasan kulitb tebal yang hanya dapat dilihat semasa waktu pembiakan atau persenyawaan. Proses persenyawaan melibatkan sepasang lintah atau lebih bertemu dan berjalin badan satu sama lain di mana setiap mereka mengeluarkan sperma ke kawasan clitellum pasangan mereka.

Sperma tadi akan masuk ke ovari tempat di mana fertilasi berlaku. Kawasan clitellum
mengeluarkan kokun gelatin yang mengandungi khasiat. Daripada kokun inilah telurtelur
lintah akan terhasil. Kokun itu tadi sama ada tertanam atau melekat di batu, kayu, daun atau akar tumbuhan akuatik. Selepas beberapa minggu atau bulan, anak lintah kecil akan kelihatan.
Lintah dari keluarga Hirudo bertelur secara kokun dan juga lendiran; manakala lintah Amazon bertelur di atas perutnya yang berpotensi menghasilkan kira-kira 300 ekor anak. Lintah dari keluarga Hirudo tidak mempunyai anggaran tepat tentang potensi anak yang dihasilkan tetapi dipercayai lebih kurang 20 hingga 200 ekor anak dan volum ini bergantung kepada 4 faktor penting:-
1. Kualiti air (julat pH antara 6.8 hingga 7.4);
2. Suhu normal (suhu air antara 15oc hingga 27oc);
3. Suasana gelap; dan
4. Gangguan paling minima.

Kokun lintah

Lintah boleh mula bertelur pada umur 3 bulan dan ke atas.
Lintah dikatakan boleh menghasilkan telur 5 atau 6 kali dalam hayatnya.

Tetapi wujud juga dakwaan saintis yang lintah akan mati selepas bertelur untuk kali kedua atau ketiga. Selepas bertelur, lintah selalunya mengambil masa 1 bulan atau lebih untuk mula bertelur buat kali seterusnya. Jangkaan kematian atau ketidakberjayaan anak dihasilkan dari telur lintah dianggarkan 5%.

Makanan

Kebanyakkan spesis lintah adalah jenis sanguivorous, iaitu mendapat makanan dengan menyedut darah dari hos (perumah) yang boleh terdiri daripada hidupan mamalia seperti binatang dan manusia, ikan, katak, dan lain-lain.
Lintah jenis ini boleh menyedut darah yang beratnya berkali ganda dari jumlah berat badannya.
Selepas kekenyangan lintah akan berehat di kawasan gelap dan terlindung untuk proses penghadaman. Proses penghadaman adalah perlahan. Lintah boleh bertahan tidak makan selama beberapa bulan (ada mengatakan sehingga 6 bulan).

Teknik Pemakanan Lintah Ternakan Komersil

Lintah ternakan komersil diberi makan ikan belut dan keli secara berjadual. Belut lebih disyorkan kerana darahnya lebih banyak dan mengandungi lebih banyak khasit seperti Omega-3 yang bagus untuk tujuan pembiakan berbanding keli. Kaedah beri makan boleh dilakukan dengan menggunakan sangkar, jaring atau cuma mata kail dengan menenggelamkan badan belut atau keli ke dalam air dengan mulut dihadapkan ke permukaan air. Sengat dan bawah bibir keli perlu dipotong terlebih dahulu sebelum diberi makan kepada lintah. Belut pula perlu diikat mulutnya yang boleh dilakukan dengan menutup kepalanya dengan kain dan diikat dengan sebaiknya.

Ini untuk mengelakkan lintah digigit belut atau termasuk ke dalam insang yang menyukarkan proses bedah siasat. Keli dibiarkan di dalam air selama 4 jam sebelum diangkat dan diperiksa atau dibedah siasat bagi memastikan tiada lintah tertinggal di dalam insang atau badan. Belut dibiarkan di dalam air selama 6 jam sebelum diangkat dan diperiksa atau dibedah siasat bagi memastikan tiada lintah tertinggal di dalam insang atau badan. Jika keli atau belut adalah makanan utama lintah dan tiada makanan tambahan (supplement) seperti booster, maka haruslah diberi makan seekor keli atau belut setiap minggu atau lebih jika lintah-lintah tadi membiak dengan banyak.

Booster disyorkan untuk menggalakkan pembiakan dan tumbesaran lintah dengan mewujudkan aggil dan plankton yang terhasil dengan tindakbalas bahan organik dalam booster dan hampas dan sisa tumbuhan akuatik seperti kiambang atau keladi bunting yang mati.

Berikut adalah cadangan sukatan booster:-
Polytank 80 Gelen
Permulaan 2kg; setiap minggu 500g ditabur di dalam setiap polytank
Kolam Batu Blok 4 X 9
Permulaan 4kg; setiap minggu 1kg
Kolam Kanvas 15 X 30
Permulaan 30kg hingga 40kg; setiap minggu 3kg

Penggunaan dalam Perubatan

Hampir 2000 tahun, lintah digunakan dalam perubatan bagi menyembukan pelbagai jenis penyakit dengan kaedah mengeluarkan darah (bloodletting). Penggunaan lintah di Eropah mencapai zaman kemuncak pada tahun 1830 hingga 1850 sehingga kekurangan bekalan lintah menyebabkan pengurangan penggunaan hidupan ini.

Kini lintah telah diiktiraf sebagai alat perubatan seperti di Amerika dan banyak negara Eropah.
Digunakan secara meluas dalam industri perubatan kosmetik seperti pembedahan kecantikan bagi menyelesaikan masalah pembuluh darah kecil tersumbat atau beku dan kekejangan otot.
Contoh penyakit yang boleh dirawat menggunakan lintah seperti:-
1. Kanser tiroid;
2. Migrain;
3. Masalah kulit;
4. Diabetes;
5. Mata bengkak, kemerahan;
6. Jerawat dan resdung;
7. Pembedahan kosmetik;
8. Membuang darah kotor; dan
9. Penggunaan lendiran lentah (hirudin) dalam merawat inflamasi, mata lebam, antibeku darah yang berguna bagi merawat penyakit jantung, darah tersumbat dan darah terlalu pekat.

Tips Penjagaan

Jangan gunakan air paip tanpa merawat dengan anti-klorin terlebih dahulu.
Air paip juga boleh dirawat dengan biarkan ia di bawah cahaya matahari selama lebih daripada 2 hari untuk menghilangkan klorin.
Jangan gunakan air sungai dan paya kerana dihuatiri terdapat anak ikan yang akan membesar dalam kolam lintah dan makan telur lintah ternakan anda.
Air semulajadi seperti air hujan dan air gunung (air terjun) juga sesuai untuk lintah tetapi mestilah diuji tahap pH.
Air hujan kebanyakan di bandar besar dan kawasan industri mempunyai air hujan yang tahap pH bawah 5.0 (berasid tinggi) yang tidak sesuai dengan lintah.
Jangan letak anak ikan untuk membunuh jentik-jentik.
Beri makan belut atau booster secara berjadual dan tidak melebihi sukatan atau dosage yang disyorkan.
Jangan biarkan badan belut atau keli yang mati terbiar di dasar kolam kerana akan mencemarkan kualiti air kolam.
Berhati-hati ketika memilih baja atau booster lintah kerana terdapat booster yang mempunyai kandungan ammonia yang terlampau tinggi.
Selalu periksa tahap pH dan suhu air (cuaca panas) anda. Sebaik-baiknya 1 minggu sekali.
Penggunaan Effective Microorganisms (EM) memang terbukti boleh merawat air tetapi sesetengah penternak lintah berpengalaman menasihatkan cuba mengelakkan penggunaan secara kerap, hanya kecuali jika kualiti air sangat teruk.
Elakkan memberi jeli darah lembu kerana darah hidupan mamalia dikhuatiri berpenyakit dan darah yang terdedah dengan udara selalunya dikaitkan dengan tercemar.
Jika lintah digunakan dalam bekam; jangan gunakan lintah yang sama kepada 2 pesakit kerana dikhuatiri penyakit pesakit 1 berjangkit kepada pesakit 2.
Lintah yang telah menyedut darah manusia tidak boleh dimasukkan semula ke dalam kolam tetapi mesti dikuarantin terlebih dahulu selama 3 bulan.
Gunakan keladi bunting, kiambang dan pokok kangkung puteri sebagai tumbuhan akuatik bagi tempat lintah berlindung, bertelur dan juga sebagai sumber atau punca menambah oksigen dalam air.
Elakkan mambakar sampah, meracun rumput atau menghisap rokok berdekatan dengan bangsal lintah. Ia akan menjejaskan ketahanan dan jangka hayat lintah selain membantutkan pembiakan.
Pastikan tangan bersih dan bebas daripada sisa kimia seperti sabun, minyak rambut, alat kosmetik dan rokok sebelum memegang lintah atau mencelup tangan ke dalam polytank.

Sejarah
Penggunaan lintah sebagai alat perubatan telah dipelopori di India pada 1000 tahun sebelum Masihi.
Dhanvantari, salah seorang dewi India, dalam Ayurveda digambarkan memegang seekor lintah di salah satu dari empat tangannya.

MEMULAKAN PROJEK PENTERNAKAN LINTAH

Menternak lintah secara komersil sangat menguntungkan kerana permintaan terhadap lintah
dan produk lintah sangat tinggi. Ia sangat popular kini kerana disebabkan kesedaran
masyarakat dunia tentang khasiat dan keefisyenan dan kadar efektif lintah yang tinggi dalam
perubatan moden dan tradisional. Selain itu, ternakan lintah ini bersifat modal sekali kerana
ia membiak pantas dan perusahaan penternakan ini dapat dibesarkan tanpa mengeluarkan
modal baru untuk membeli induk tetapi cuma tidak menjual keseluruhan lintah dan menyimpan
untuk penternakan kali seterusnya.
Tetapi adalah dinasihatkan supaya bakal penternak mengikat kontrak perjanjian jual beli
dengan syarikat penghasil produk lintah atau pemborong lintah. Cara mudah ialah dengan
mencari syarikat yang menawarkan perjanjian contract farming atau perladangan kontrak
yang menjanjikan akan membeli lintah daripada anda apabila tiba waktu menuai dengan harga
yang telah ditetapkan. Syarikat yang menawarkan perjanjian contract farming ini selalunya
syarikat yang sudah lama bertapak, mahir dalam ilmu lintah. Jika anda mengikuti kursus yang
dianjurkan oleh syarikat ini selalunya akan ditawarkan mengikuti pakej penternakan yang
sekaligus mengikat perjanjian dengan syarikat tersebut.
Harga jualan standard lintah kepada orang tengah atau syarikat kontrak adalah dalam
lingkungan RM50-00 hingga RM80-00 per kg dalam kauntiti pukal. Harga jualan lintah dalam
pasaran kecil seperti menjual kepada kumpulan atau individu pengamal perubatan moden atau
tradisional, kemungkinan tinggi sedikit kerana kuantiti dibeli adalah sedikit. Dianggarkan
RM80-00 hingga RM100-00 per kg.
Carta Harga Jualan (standard dan akan berubah mengikut pasaran)
Lintah jumbo (menopause) RM50 – RM80/kg (60 – 100 ekor = 1kg)
Lintah matang RM120 – RM150/kg (130 – 150 ekor = 1kg)
Lintah muda RM220/kg (200 – 250 ekor = 1kg)

Hasil jualan lintah mengikut harga berdasarkan saiz untuk satu polytank yang berjaya tanpa
masalah kritikal, penyeliaan dan penjagaan yang rapi, makanan yang cukup dan berjadual,
kualiti, suhu dan tempat ternak yang kondusif dan menyerupai habitat asal lintah dan dapat
meminimumkan gangguan bersifat gegaran atau kehadiran bahan kimia berbahaya.
Hasil akan berkemungkinan menjadi lebih tinggi dengan usaha gigih dan izin Allah. Selalunya
hasil tinggi akan dinikmati oleh penternak untuk batch kedua kerana induk lintah yang lebih
banyak dan pengalaman yang lebih meluas.
Mengikut kajian yang dijalankan oleh sintis dan juga hasil pengalaman yang dikongsi oleh
penternak lintah yang telah lama menceburi sama-sama menyatakan fakta bahawa lintah
mudah membiak dalam kawasan kecil dan sempit kerana lebih mudah bertemu. Lintah juga
tidak berapa sesuai diternak dalam kolam simen kerana wujudnya kehadiran kapur dan asid
simen. Walaupun asid simen telah dihilangkan namun para pemborong dan syarikat pemproses
produk lintah tidak menggemari lintah hasil ternakan kolam simen kerana pasif dan kandungan lendir atau hirudin sedikit.

Kolam kanvas dianggap pesaing hampir kepada kaedah polytank. Namun kaedah kolam kanvas
telah dibuktikan melalui testimonial penternak lama yang mengatakan ia sangat leceh,
memerlukan komitmen dan penyeliaan yang tinggi; contohnya angin boleh membawa sisa racun
rumput walaupun kawasan diracun berjauhan menyebabkan merosakkan tumbuhan akuatik dan menjejaskan hayat dan pembiakan lintah, bersaiz besar yang menyukarkan proses pembiakan berlaku, menggunakan ruang yang besar, sukar untuk memperbaiki keadaan jika berlaku masalah; contohnya pemindahan lintah.
Masalah kolam kanvas ini kesemuanya dapat diselesaikan oleh kaedah polytank (dengan izin
Allah) yang mudah diselenggara kerana kecil, bertudung dan tinggi dapat mengelak dari angin
membawa sisa racun, kecil dan sempit bagus untuk pembiakan, tahan lama kerana diiktiraf
oleh ISO dan SIRIM.

2 saja masalah kaedah polytank ialah pertama: polytank tidak dapat digunakan sampai bilabila
dan mempunyai tempoh masa sesuai iaitu sehingga 7 atau 10 tahun dan kedua: polytank mudah menyerap haba kerana ia plastik dan berwarna hitam. Masalah-masalah tersebut boleh diatasi dengan membuat bumbung net orkid hitam dengan ketelusan 50% hingga 70% halang cahaya dan harga polytank bukannya mahal cuma RM100 – RM120 setong, itu pun ditukar selepas satu jangka masa yang agak lama.

BOOSTER BIO-BOOM

Nama Booster BIO-BOOM tercipta hasil kombinasi perkataan booster yang bermaksud
penggalak atau pemangkin; bio – singkatan daripada perkataan biologi iaitu hidupan atau
semulajadi dan boom bermaksud impak besar.
Booster BIO-BOOM boleh dijadikan makanan alternatif bagi menggantikan belut atau keli
atau juga menjadikan ia sebagai asas (foundation) kolam atau polytank lintah anda
menggantikan tanah selut atau pasir.
Booster BIO-BOOM dirumus khas daripada baja kompos, bahan-bahan organik, zeolite,
kalsium dan fosforus yang diproses secara vermikompos (penguraian cacing) yang membantu
mengurangkan kadar ammonia dan menyahkan toksik berbahaya. Berikut adalah manfaat
penggunaan produk ini:-
Menggalak pembiakan dan tumbesaran lintah;
Menjadi makanan alternatif dengan mewujudkan microflora (plankton, agil, turbiditi)
sekaligus menjimatkan kos pembelian belut; Mengawal suhu air; Kandungan zeolite dapat mengurangkan ammonia dan komponen gas-gas bersifat nitrogeous dalam air; dan
Menyuburkan tumbuhan akuatik seperti keladi bunting, kiambang dan kangkung puteri.

Leeches

2009-02-19T19:54:00.004+08:00

Leech Therapy
They bite, slither, and slide -- and they save fingers and lives.

While the sight of a wriggling, blood-sucking leech may make many people feel queasy, the spineless worms can also help people feel better -- as NATURE's BLOODY SUCKERS shows. The ancient physician's art of using leeches has made a modern medical comeback: the worms help doctors do everything from reattach severed fingers to treat potentially fatal circulation disorders.

Leeches have been used by physicians since ancient times.

Leeches -- which are found all over the world, living mostly in fresh water -- have long had a place in the doctor's medical kit. Five thousand years ago, Egyptian medics believed that letting a leech sip a sick patient's blood could help cure everything from fevers to flatulence. And in medieval Europe, leeches were so closely associated with doctors that physicians were called "leeches" -- and they used millions of the parasites annually to treat patients.

In the 20th century, however, most doctors turned away from the worms, which in nature feed on everything from frogs to alligators. A few physicians, however, saw that leeches might play a special role in certain kinds of surgery, by helping promote blood flow to damaged tissue. That's because when leeches bite a victim, their unique saliva causes blood flow to increase and prevents clotting. As a result, once bitten, victims can bleed for hours, allowing oxygenated blood to enter the wound area until veins re-grow and regain circulation.

The leech is invaluable in microsurgery when faced with the difficulties of reattaching minute veins. Ears have such tiny veins that, in the past, no one was able to successfully reattach them. Then, in 1985, a Harvard physician was having great difficulty in reattaching the ear of a five-year-old child; the tiny veins kept clotting. He decided to use leeches and the ear was saved. This success established leeches in the modern medical world. Since then, leeches have saved lives and limbs, reducing severe and dangerous venous engorgement post-surgery in fingers, toes, ear, and scalp reattachments; limb transplants; skin flap surgery; and breast reconstruction.
Perhaps the best known advocate of medical leeches is Roy Sawyer, an American researcher. Several decades ago, he recognized the potential benefits of "leech therapy" and started one of the world's first modern leech farms. Today, the company -- Biopharm, based in Britain -- provides tens of thousands of leeches every year to hospitals in dozens of countries. Two species are commonly used in leech therapy, which can last for up to 10 days.

Leeches can help promote blood flow to damaged tissue.

Leeches do have their downsides. Sometimes, they slip off patients and reattach themselves in unwanted places. And no matter how helpful, some patients simply can't stomach the thought of a blood-sucking parasite burrowing into their skin. So some scientists have developed a "mechanical leech" that can perform some of the same duties -- without the gross-out factor.

"In the case of the leech in medicine, we think we can improve on nature," says Nadine Connor, a University of Wisconsin at Madison scientist who in 2001 helped develop the mechanical leech. The device, which looks a little like a small bottle attached to a suction cup, delivers an anti-clotting drug to damaged tissue and then gently sucks out as much blood as needed. And, unlike real leeches, the mechanical version is insatiable and can remove as much blood as doctors think is necessary (real leeches drop off when engorged with blood).

"But perhaps the mechanical device's biggest advantage is that it is not a leech," says Connor. "People don't want this disgusting organism hanging on their body. This added psychological stress for both patient and family members compounds an already difficult situation."

Other physicians, however, still swear by the natural wrigglers. Leeches, they say, are a nearly perfect -- and self-reproducing -- surgical tool. And the leech's bite, they add, isn't nearly as bad as its reputation.

Application

Leeches can be used in many applications especially for medical and cosmetic purpose. Traditional use of leeches is by letting the leech to suck blood of the patient’s body to relief symptoms like headache and join pain. Leech oil is known to the local community for enhancing
the sex capability of man. In India, it is used for preventing hair loss. Chinese medicine use leech as and ingredient for various treatments. Modern medicine uses the ingredient extracted from leech to cure blood related diseases. Leeches have been used for medical purposes since over 2000 years ago.
One example is using leeches to suck out the blood in the body to achieve the healing purpose. Today there is a real clinical application in this method; they are of great value to plastic surgeons when venous congestion of skin and muscle flaps is a problem. The leech can suck the blood at the joint where blood is clogged and make it flow again. Leeches today are used in plastic and reconstructive surgery worldwide. There is also successful ongoing research into relieving symptoms of osteoarthritis by using leech. One bigger progress in using leeches in medical field is that they have been approved in America for use in therapy purposes. Live leech are being distributed to various location in the country and also worldwide for use. After sucking the blood, leeches are treated in the same way as other blood treatment procedure that they only can be used on the same patient. This is mainly to prevent the spreading of disease that carried by blood. Other usage of leeches also includes treatment of black eyes. Hirudin, the anti-coagulant from leech can be used in the treatment of inflammation of the middle ear. It is also being developed for experimental use as a systemic anticoagulant, and may prove useful in invitro blood sampling. By extracting the anti-clotting serum from the leech researchers are isolating new pharmaceutical compounds for eventual treatment of heart diseases.
From the history, leech was indispensable in 19th Century medicine for bloodletting, a practice believed to be a cure for anything from headaches to gout. The medicinal leech is getting more popular in modern medicine thanks to the work of Dr. Roy Sawyer, an American scientist who established the world’s first leech farm. Thousands of patients owe the successful reattachment of body parts to technological advances in plastic and reconstructive surgery; at least some of these operations might have failed if leeches had not been reintroduced into the operating room.
The reason for using leeches in surgical procedures is actually very straightforward. The key to success is from what contain in the leech bite, which punctures a wound that bleeds literally for hours. The leech’s saliva contains substances that anaesthetize the wound area, dilate the blood vessels to increase blood flow, at the same time prevent the blood from clotting. Usually the surgeon can get blood to flow in the reattached arteries but not veins. With the venous circulation severely compromised, the blood going to the reattached finger becomes congested; the reattached portion turns blue and lifeless and is at serious risk of being lost. At this time leeches start to play their major role in letting go of the clotting blood. Leech farming is an industry that is getting more popular as more leech usage has been established. One reason is also due to the number of leeches getting lesser in the wild, after the heavy usage of insecticide and pesticide. More researches are on going in discovering the uses of leech that can help us to cure the blood related problem such as heart diseases and also high cholesterol in our body. The role of leech will change from a blood sucking creature that is feared by many people to a great helper in our health.

Leeches

Biology

Illustration: K. Dempsey

Leeches are annelids or segmented worms, and although closely related to the earthworms, are anatomically and behaviourally more specialised.

The bodies of all leeches are divided into the same number of segments (34), with a powerful clinging sucker at each end (although the anterior, or front sucker can be very small). Body shape is variable, but to some extent depends on the degree to which their highly muscular bodies are contracted. The mouth is in the anterior sucker and the anus is on the dorsal surface (top) just in front of the rear sucker.

Leeches usually have three jaws and make a Y-shaped incision. The Australian land leech has only two jaws and makes a V-shaped incision. Australian leeches can vary in size from about 7 mm long to as much as 200 mm when extended.

Different Types

Leeches are grouped according to the different ways they feed. One group (the jawed leeches or Gnatbobdellida) have jaws armed with teeth with which they bite the host. The blood is prevented from clotting by production of a non-enzymatic secretion called hirudin. The land leech commonly encountered by bushwalkers is included in this group.

Jaw drawings, after M. Stachowitsch The Invertebrates - an Illustrated Glossary

A second group (the jawless leeches or Rhyncobdellida) insert a needle-like protrusion called a proboscis into the body of the host and secrete an enzyme, hemetin which dissolves clots once they have formed. Leeches which live on body fluids of worms and small freshwater snails possess such an apparatus.

A third group, (the worm leeches or Pharyngobdellida) have no jaws or teeth and swallow the prey whole. Its food consists of small invertebrates.

Respiration

Respiration takes place through the body wall, and a slow undulating movement observed in some leeches is said to assist gaseous exchange. Aquatic leeches tend to move to the surface when they find themselves in water of low oxygen content. As a fall in atmospheric pressure results in a small decrease in dissolved oxygen concentrations, rising leeches in a jar of water provided nineteenth century weather forecasters with a simple way of predicting bad weather.

Sense Organs

Sensory organs on the head and body surface enable a leech to detect changes in light intensity, temperature, and vibration. Chemical receptors on the head provide a sense of smell and there may be one or more pairs of eyes. The number of eyes and their arrangement can be of some use in Identification, however to properly identify a leech, dissection is required.

The Rhyncobdellids are capable of dramatic colour changes, and although not an attempt at camouflage, the significance of this behaviour is unknown.

Reproduction

As hermaphrodites, leeches have both male and female sex organs. Like the earthworms they also have a clitellum, a region of thickened skin which is only obvious during the reproductive period. Mating involves the intertwining of bodies where each deposits sperm in the others' clitellar area. Rhyncobdellids have no penis but produce sharp packages of sperm which are forced through the body wall.

The sperm then make their way to the ovaries where fertilisation takes place. The clitellum secretes a tough gelatinous cocoon which contains nutrients, and it is in this that the eggs are deposited.

The leech shrugs itself free of the cocoon, sealing it as it passes over the head.

The cocoon is either buried or attached to a rock, log or leaf and dries to a foamy crust. After several weeks or months, the young emerge as miniature adults. Studies show that the cocoons are capable of surviving the digestive system of a duck. Leeches die after one or two bouts of reproduction.

Feeding

Most leeches are sanguivorous, that is they feed as blood sucking parasites on preferred hosts. If the preferred food is not available most leeches will feed on other classes of host. Some feed on the blood of humans and other mammals, while others parasitise fish, frogs, turtles or birds. Some leeches will even take a meal from other sanguivorous leeches which may die after the attack.

Sanguivorous leeches can ingest several times their own weight in blood at one meal. After feeding the leech retires to a dark spot to digest its meal. Digestion is slow and this enables the leech to survive during very long fasting periods (up to several months).

Foraging - How does a leech go about searching for a blood meal?

A hungry leech is very responsive to light and mechanical stimuli. It tends to change position frequently, and explore by head movement and body waving. It also assumes an alert posture, extending to full length and remaining motionless. This is thought to maximise the function of the sensory structures in the skin.

In response to disturbances by an approaching host, the leech will commence "inchworm crawling", continuing in a trial and error way until the anterior sucker touches the host and attaches. Aquatic leeches are more likely to display this "pursuit" behaviour, while common land leeches often accidentally attach to a host.

The Bite

When a jawed leech bites it holds the sucker in place by making its body rigid. Using its semi circular and many toothed jaws like minute saws, it then makes an incision in the skin and excretes a mucous from the nephropores (external openings from the kidney-like organs). This helps the sucker to adhere. A salivary secretion containing the anticoagulant and a histamine floods the wound and the leech relaxes its body to allow the blood to be ingested. This mixture allows the blood to flow and also prevents clotting once inside the leech. A bacterium in the gut of the leech assists the digestion of the blood, and it has been shown that the type of bacterium varies with the type of host on which the leech feeds. The bacterium also prevents growth of other bacteria which may cause the ingested blood to putrefy.

Habitat

Most leeches are freshwater animals, but many terrestrial and marine species occur.

Land leeches are common on the ground or in low foliage in wet rain forests. In drier forests they may be found on the ground in seepage moistened places. Most do not enter water and cannot swim, but can survive periods of immersion.

In dry weather, some species burrow in the soil where they can survive for many months even in a total lack of environmental water. In these conditions the body is contracted dry and rigid, the suckers not distinguishable, and the skin completely dry. Within ten minutes of sprinkling with a few drops of water, these leeches emerge, fully active.

Freshwater leeches prefer to live in still or slowly flowing waters, but specimens have been collected from fast flowing streams.

Some species are considered amphibious as they have been observed in both terrestrial and aquatic habitats.

Uses in Medicine

For over 2000 years, leeches were needlessly applied for many ailments as an adjunct to blood letting. Their use in Europe peaked between 1830 and 1850, but subsequent shortages led to a decline in their use. Today there is a real clinical application in that they are of great value to plastic surgeons when venous congestion of skin and muscle flaps is a problem.

Leeches are treated in the same way as blood products and are reused only on the same patient.

Medical use of leeches also includes treatment of black eyes, and hirudin is used in the treatment of inflammation of the middle ear. Hirudin is also being developed for experimental use as a systemic anticoagulant, and may prove useful in invitro blood sampling.

Repellents

The most common enquiry regarding leeches concerns repellents. It is unknown whether a specific preparation is commercially available but there is a plethora of tried and tested, but unproven leech-protection ideas. These include a lather of bath soap smeared on exposed parts and left to dry, applications of eucalyptus oil, tropical strength insect repellent, lemon juice and impenetrable barriers of socks and pantyhose.

The Wound

The presence of hirudin in the wound following a leech bite may cause oozing to continue for several hours. Although inconvenient, blood loss is not significant.

Gut bacteria can cause wound infection. In the post-operative use of leeches this is closely monitored and dealt with by use of the appropriate antibiotic.

There may also be a delayed irritation and itching after a bite. There appears to be no support for the theory that mouthparts left behind after forced removal of the leech causes this reaction.

Can leeches transmit disease? There is no evidence to suggest that they do. The presence of trypanosomes, (malarial parasites), in the gut of jawless leeches has been noted, but jawed leeches do not appear to be hosts.

Allergy to leech bite has been reported. Medical opinion should be sought, depending on the severity of the reaction.

The leech was indispensable in 19th Century medicine for bloodletting, a practice believed to be a cure for anything from headaches to gout. Leeching was largely abandoned as medical science advanced, only occasionally being called upon to treat bruising and black eyes. However, the medicinal leech is making a comeback in modern medicine thanks in part to the work of Dr. Roy Sawyer, an American scientist who established the world's first leech farm.

Based at Hendy near Swansea, South Wales, Biopharm is home to over 50,000 leeches which are supplied to hospitals and research laboratories around the world.

Thousands of patients owe the successful reattachment of body parts to miraculous technological advances in plastic and reconstructive surgery; at least some of these operations might have failed if leeches had not been reintroduced into the operating room. The appendages reattached include fingers, hands, toes, legs, ears, noses and scalps.

The pioneering use of leeches in modern plastic and reconstructive surgery can be attributed to two Slovenian surgeons, M. Derganc and F. Zdravic from Ljubljana who published a paper in the British Journal of Plastic Surgery in 1960 describing leech-assisted tissue flap surgery (in which a flap of skin is freed or rotated from an adjacent body area to cover a defect or injury). These surgeons credit their own use of leeches to a Parisian surgeon, one Philippe-Frédéric, who reported in 1836 that he had used leeches to restore circulation following reconstruction of a nose.

The rationale behind the use of leeches in surgical procedures is fairly straightforward; nonetheless, it is subject to misunderstanding, even by clinicians. The key to success is the exploitation of a unique property of the leech bite, namely, the creation of a puncture wound that bleeds literally for hours. The leech's saliva contains substances that anaesthetise the wound area, dilate the blood vessels to increase blood flow, and prevent the blood from clotting.

Microsurgeons today are adept at reattaching severed body parts, such as fingers. They usually have little trouble attaching the two ends of the arteries, because arteries are thick-walled and relatively easy to suture. The veins, however, are thin-walled and especially difficult to suture, particularly if the tissue is badly damaged. All too often the surgeon can get blood to flow in the reattached arteries but not veins. With the venous circulation severely compromised, the blood going to the reattached finger becomes congested, or stagnant; the reattached portion turns blue and lifeless and is at serious risk of being lost. It is precisely in such cases that leeches are summoned.

FILTRATION

2009-02-15T11:07:00.029+08:00

Filtrations basics
The circle of life may come to mind when reviewing a picture of the nitrification cycle. Yet it is key to mother natures design of biologically filtering waste from water. However, several other
mechanics should take place in your pond if we are expected to achieve an environment in which we can expect to keep healthy aquatic life successfully. Filtering the ponds various forms of debris and waste products takes several steps and can be done so many different ways. The better we incorporate the basic features, the more likely we are to have success.When filtering waste from a pond, it is better to Mechanically filter it before continuing onto the Bio-Filtration. This permits the Bio-filter stage to perform optimally.

Should you go for a gravity or for pump fed filtration system?
We get a lot of queries about this particular issue and it is clear that this is an issue that a pond novices just don't understand all that clearly. Note that this choice only applies to low pressure filter systems rather than closed circuit high pressure systems (where it makes no difference - you can locate a high pressure filtration system just about anywhere.

Generally low pressure systems use less electricity and are more efficient in giving you maximum water movement through your filter systems with the lowest possible energy input (a good thing!). Low pressure systems have one drawback however in that their installation is not as easy as with a high pressure filter system. This is because one leg of a low pressure system will rely on gravity, either to feed water to the filters, or to return water back from the system to the pond. It is thus very simple, but it takes some experience to get your head around it.

Gravity Fed Filtration. A gravity fed filter system relies on a water from the Koi pond over flowing into the filter systems. The pump that drives the system then sucks water from the final stage of the filter system and pushes it back into the pond, causing the water level in the pond to rise and to overflow and re-fill the filters.

If this pump is turned off for any reason then the pond will overflow for a while into the filters which will fill up to the same level as the pond and then coming to what we call the idle state - in other words the water levels in the pond and the filters are exactly the same.The water levels in the pond are thus critical. If the water level in the pond drops for any reason you may find that the water flow rate feeding the filters slows down to the point where the pump on the other end empties the filters faster than they can be filled, resulting in the pump sucking dry and burning out on you.

If the pond is over full there shouldn't be a problem however - your filters should always be at the same height as the pond so there will be no chance of the filters overflowing. It is always a good idea to install an overflow into your pond so that that if the pond overfills - say due to rain - the excess water can be drained off preventing the filter chambers from overflowing and allowing all your ActiBioBed media to escape into your garden... The other challenge that a gravity fed filter system presents is that unless you do your design carefully and with some forethought it is very easy to get flow rates wrong. Trust us, each pond IS different and in some instances we have seen ponds trying to feed a filter with a small 50mm pipe as the sole feed... and this on 15 000 litres of pond water. It simply isn't going to work no matter what you do!

The secret to success with a gravity fed filter system is to allow yourself as much headroom as possible - such that the filters can run with at least double the anticipated flowrate that you intend pushing through your filters. If you over specify this you can do no harm. If you under specify it you will regret it for all time. Location of the system will depend on your situation. As with all filter systems the closer to the pond the better in terms of flow rates and energy efficiencies. Try and aim at putting the pump side of the filter as closer to the pond side - because if you get your flow rates correct gravity will 'pump' the water to the system to you for free. All your pump has to do it move the water a short distance back to the pond, thereby maximizing your efficiency of your pump.

Pump Fed Filtration. A pump fed filtration system relies on a pump to feed the filters and then gravity to move the water back to the pond. Literally the filters overflow with the intention being that the water from the filters overflows back to the pond.The potential headache for these filters is that if the pump is capable of delivering more water to the filters than gravity is capable of returning back to the pond then the filters will overflow and you will be picking up ActiBioBed media all over again.

Gravity is not the strongest of pumps however. the higher your filters stand above your pond the stronger the gravity pump becomes - but even so there are limits. No matter what you do getting 20 000 litres per hour through a 50mm pipe is not going to happen...(!)

Also, if you have the returns from your filter system returning below water level you will find odd things happening when the system starts up from idle. The pond water creates a small resistance to the flow of water and when the system starts up this can cause the water in the filters to backup and, yes, overflow! The solution is to use large bore pipes - and again to over specify your return pipe work by a factor of at least 2.

Surging is also an effect unique to water flowing out from a vessel via a constriction, such as a pipe. What happens is that as the vessel starts to overflow water escapes via the outlet pipe at an ever increasing rate pulling air in as it does so. Eventually if the flow rate is fast enough the air trapped in the pipe is expunged and the water velocity in the pipe increases. As it does so it can exceed the fill rate of the vessel and hence begin to suck air again. The process repeats infinitely and is referred to as surging.In and of itself surging is not a problem. Air trapped within the water return stream is also not problematic although it does cause bubbling at the point of entry of the return water to your pond if your water return is below surface level. Surging can however result in filters overflowing if the flowrates are large enough relative to the diameter of pipe used to carry the water back to the pond.

The general rule of thumb with pump fed filters and gravity returns is to use as large a diameter pipe as possible, and then to over do it! If you return water below the surface of your pond note that you are likely to get some bubbling taking place.In a pump fed filter system the general rule is to locate the pump as close to the pond and the filters as possible to minimize the piping run it needs to deal with. Again, if you get the calculations correct gravity can 'pump' the water back to the pond for you for free.

The mechanical. The purpose of this stage is to trap as much of the crud as possible. Such as leaves, sticks and any other items like fish waste that have settled to the bottom. Also to trap debris floating in or on top of the water.

Mechanical filtration takes place normally at the very start of your Koi pond filtration system. It's role is to remove any solid (organic) material from the system before the pond water reaches the sensitive biological filtration stage. Organic wastes that reach the bio filter stage are not beneficial in any way. An ideal mechanical filter removes ALL solid wastes so that the biofilter can operate with almost exclusively nitrification bacteria and hence optimise the efficiency of the ammonia breakdown process known as the nitrogen cycle.

There are a few ways of achieving this process. In human swimming pools, sand filters are highly effective at trapping solids for easy backwashing and rinsing away and there seems to be a disturbing trend, particularly in South Africa of using these on Koi pond systems. However, there are some major differences between swimming pools and Koi ponds, the biggest being that Koi ponds are supposed to keep things alive. Sand filters have no place in Koi ponds and especially not as a primary mechanical filtration devices. Find out why here!

The other primary means of removing solids is by using a vortex chamber. These are typically big, the bigger the better and pond water is allowed to slowly circulate in the chamber, allowing enough residence time for solid particles that are denser than water to sink and collect at the bottom from where they can be purged. Vortexes make the dangerous assumption that all solids are denser than water. This is often not the case - leaves, gunge, rotting dead algae killed by the UV etc often floats. In many more instances the solid materials density is so close to that of water that even in a massive vortex the particles simply do not have enough time to settle out.

Heterotrophic bacteria that can negatively compete with the nitrification bacteria in the biofilter (see inorganic wastes) don't mind what form their organic solid food takes. As long as it's there, they'll pitch up for the meal. And pitch up in great numbers at that, competing with and hampering the performance of the much needed nitrification bacteria. When heterotrophic bacteria appear in great numbers so do pathogens and unwanted, harmful bacteria (to Koi anyway). You may not see them, but your Koi know they're there and at the first sign of weakness an apparently otherwise healthy Koi can easily be overwhelmed and succumb to a secondary infection that would never have troubled it ordinarily. Something simple like a cut or a graze, handling wound or a even bird peck becomes potentially life threatening. Minor cuts and damage should be no problem for a healthy Koi in a healthy pond! Often two or three vortexes are linked in series to enhance their efficiency. However, the volume of waste material gathered in the second or even third chambers is often not sufficient to justify the additional cost save to all but the hardened Koi purist. Normally a bigger first vortex would perform better overall.

There are many variations on mechanical filtration involving brushes, foam blocks, and so forth and so on. A quick browse on the Internet will provide you with many such solutions - Japanese matting incidentally is NOT used for mechanical filtration - it is a bio media and acts as a biological filter. It is not operating at optimum efficiency if it is not free from organic debris. There are two problems with this style of mechanical filter. The first is that of maintenance. As they collect solid debris much like they're supposed to, they have to be regularly cleaned to maintain their efficiency and to get rid of the muck that they accumulate. This should be done ideally every day if you want to avoid high bacterial counts - heterotrophic bacteria colonise alarmingly quickly.

Secondly, no matter how fine the medium, a percentage of solid material is going to make it straight through the media. These are typically the smaller particles that have been broken up or break off from the media as bacteria munch away on them. A significant proportion thus finds its way into the biological filter, which, being cleaned far less often (because the nitrification bacteria take a long time to colonise you do not want to disturb them more than is absolutely necessary - ideally never) than the mechanical filter material. Once in the bio filter there is a two fold effect. The heterotrophic bacteria quickly build up in numbers and start competing for space with the nitrification bacteria, as well as adding to the ammonia load. Now, because this is taking place you are also forced to clean out the bio filter media more often causing severe disruption to the nitrification bacteria colonies and hence to the overall nitrification process. This is turn can be severely problematic for your Koi and about the only solution is to reduce or halt feeding, and then gradually building up again as the beneficial (nitrifying) bacterial colonies take hold once more.

And then you try telling a pond full of hungry Koi that the diet is for their own good! Organics in the bio filter are thus a double whammy and one you and your Koi can live without. Over the years the benefits of brilliant mechanical filtration as offered by the Answer easily outweigh the initial cost. It simply has no equal.

Examples of mechanical filters; Skimmer, screens in front of intakes, filtering media, brushes, pump baskets and settling tanks to name a few. Surface debris is removed using skimmers. Since crud settles, using a bottom drain as a source for intake permits this crud to be removed from the pond to some type of separation chamber. Screens or baskets in front of pumps are important in keeping pumps from clogging. They also prevent damage to the pumps impellors.

Bio Filtration. Biological filtration is not a difficult concept to understand. It's at the heart of the nitrogen cycle and is responsible for removing all the dissolved wastes that would otherwise accumulate in your Koi pond and kill all your Koi. If left unattended, dissolved wastes in the form of ammonia can wipe out a Koi population in a matter of days.

The nitrogen cycle is explained under Inorganic wastes. An effective nitrogen cycle, one in which all ammonia is completely broken down into much less harmful nitrates requires an effective 'reaction'. It's elementary chemistry and the only uncertainty in the entire cycle is the nitrifying bacteria themselves. If they're not present, the 'reaction' cannot take place. If there are not enough of them present, then the reaction cannot proceed to completion - in other words, not all the ammonia and nitrites will be 'reacted' into nitrates, and the pond water will have to make a second or third pass through the filter.

I have stressed the importance of fish stocking densities as much as I can. It cannot be over emphasized enough. Koi are tough fish. But with a vastly increased density per cubic meter of water as we find in Koi ponds, the stresses placed in the quality of the water in which they live are enormous. After feeding, ammonia levels in the pond will greatly exceed those as found in a natural lake or Koi mud pond. This is a situation that Koi can tolerate but should not have to! Prolonged exposure to ammonia is dangerous and will wear the Koi down until eventually an opportunistic bacterial infection or disease breaks out and kills the Koi (which under normal high water quality circumstances it would have been to easily resist).

The point should be clear that the role of the biofilter is to remove as much of the ammonia as it can as fast as possible. Speed is everything in this process and it is vital that the bio filter be able to remove ALL the ammonia and ALL the nitrites produced in a single pass of pond water. It simply is not good enough if any nitrite or ammonia makes it back into the pond.

Why is this so important? If you consider a Koi pond of say, 10 000l. The filtration system should turn over this pond volume once every two hours as a rule of thumb. This means that if all the water in the pond passes through the filter system once, it will take 2 hours to reduce the ammonia concentration down to zero.

Note that it is a dangerous assumption to make that the water is perfectly evenly distributed and that each liter will make it through the filtration system every complete cycle! It gets even worse though. If the ammonia concentration at the start of the filtration process is 100 mg/l by way of example let's see what happens over a two hour period in our 10 000l pond. At the start of the process, in a Koi pond of 10 000l we will have a total of 10 000 x 100 = 100 000 mg of ammonia. After 24 minutes, 20% of the pond volume (2 000l) will have been circulated through the filter system. Assuming we have a bio filter that is capable of completely removing all ammonia and nitrites converting them into nitrates (plant food) the amount of ammonia in the pond will have dropped by 20%. It will now be 2 000l x 100mg = 20 000mg less than it was before.

This means that the concentration of the ammonia in the pond will be reduced to 80 mg/l. Now consider what happens over the next 24 minutes. Again, another 2 000l of pond water passes through the filter system, and all the ammonia in this water is removed. Because the CONCENTRATION however is now LOWER (at 80 mg/l) the MASS of ammonia removed is LESS. 2 000l x 80 mg/l = 16 000mg of ammonia will have been taken out over this time interval. Now the concentration of ammonia in the Koi pond is our starting mass of 100 000mg less the mass removed in the first 24 minutes of 20 000mg and less the mass removed in the next 24 minute interval of 16 000mg, which leaves us with a total of 64 000mg still in the pond water. This is a concentration of 64mg/l.

Can you see that the rate at which ammonia is removed depends on the concentration of the ammonia in the water to begin with? It will take considerably longer than 2 hours, even in a perfectly mixed pond to reduce the concentration of ammonia to zero. If even only a little ammonia is recycled to the pond from the bio filter because there is inadequate bio filtration taking place, the time taken to reduce the ammonia to zero will increase dramatically. This increases the exposure period of the Koi to the ammonia, as well as the concentration levels that the poor Koi have to suffer with. There is one obvious solution which is to increase the rate of turnover through the filtration system. However, if the water passes through the filter system too quickly, the bacteria will not have enough time to munch all the ammonia - it will simply pass through too quickly.

Yes, you can run two or three systems in parallel and increase your performance that way. However, consider the practicalities and the expense of doing this. Bigger pumps mean more electricity. More biofilters mean more expense. More maintenance. Etc. No doubt there are sufficient fanatics out there who will take the hobby to this level and I encourage them to do so, but for the average Koi keeper this is simply not a practical route to adopt. As I've also said before, Koi are tough. The only time you'll know anything is wrong will be when it's too late. It may even take a few years - when the Koi are nice and big, and have had a good feed in the middle of summer when it's warm and they're eating like the pigs that they are and the bio filter hasn't been properly cleaned for a week or two and so forth and so on until a combination of circumstances fall into place that leads to disaster. It only has to happen once.

Water quality is critical to Koi keeping. Biological filtration is critical to water quality. Superior performing bio filters that can expand to accommodate growing Koi and increased feeding levels are what I would consider an 'essential first purchase above all else' necessity. Responsible for biologically converting organic wastes from animals and plants to water, new cells and gases. Bacteria thrive in a ph range from 6.5 to 8.5 and will not survive at a ph of less than 4.3 or above 10.5. Since fish release ammonia, then this toxic chemical requires some sort of bio-filtration to convert it to a final product which is not toxic.

Bacteria: There are both Pathogenic (Bad Bacteria) and Non pathogenic (Good Bacteria) Aerobic (require oxygen) and Anaerobic (absence of oxygen) bacteria. Since pathogenic (generally anaerobic) bacteria cause disease, it is preferable to introduce and promote growth of a larger number of non pathogenic aerobic bacteria.

The bio-filters need to provide adequate media surfaces for bacteria to flourish when environmental demands increase. Over stocking a pond is a common mistake made by pond keepers that ends with fish mortality. Most lakes have a smaller ratio of fish to water volume
then the ponds most of us create in our own yards. Since the good bacteria attach to and grow on the media, flowing water helps wash away decaying bacteria and bring fresh chemicals. The more media surface, the more good bacteria the filter can support. Bacteria is abundant throughout the pond in the water and on all pond surfaces. Increasing the oxygen levels also benefits the ability for bacteria to flourish.

Chemical filtering. Since the Nitrification cycle is a filtering process, it should be understood well if you plan on keeping fish. Other chemical filtering requires addition of commercial products to routinely break down biologically and degrade most forms of waste present in typical Koi ponds. This method breaks down not only fish waste, it breaks down leafs and other debris that have fallen into the pond. It can remove pesticides, odors, organic waste, excess nutrients and other harmful chemicals from your pond.
The Nitrification Cycle.
Fish release Ammonia; The Nitrosomonas bacteria consume the Ammonia and release a chemical called Nitrite. The Nitrobacter bacteria consume the Nitrite and release a chemical called Nitrate. Nitrates are not harmful to fish till very high levels. Nitrates are consumed by Algae and plants.
Two Good Bacteria's;
Nitrosomonas bacteria,
Nitrobacter bacteria.

Understanding more about the Nitrification Cycle.
The Nitrification Cycle is the process of fish wastes and other debris being broken down by different bacteria's in your pond.

Ammonia: (toxic to fish) Your fish release ammonia primarily through gill tissues and some through kidney functions. Once Ammonia is in the water, a good bacteria called "Nitrosomonas" develops and consumes the Ammonia. As byproduct, it releases a chemical called Nitrite.

Nitrite: (toxic to fish) Once Nitrite is in the water, another good bacteria forms called "Nitrobacter". As a byproduct, it releases a harmless chemical called Nitrate.

Nitrate: Plants and algae consume Nitrates. If you have no plants, then Nitrates will continue to increase to levels that could cause sickness in the fish. Normally Nitrates don't bother fish. If the Nitrate
levels continue to increase past 60 ppm, then they start to become a concern. Reaching levels of 200 ppm will then become a factor that may stress the fish and cause some ill conditions.
Water changes are a quick means to reduce Nitrate levels. Water changes of 5-10% each week should be done on a regular bases as a means to keeping good water quality and healthy fish. Keeping water Hyacinth plants in the pond are very effective in reducing Nitrate levels. A note about the above bacteria. Over time, the bacteria consume the carbonates which are the buffers for your PH. Be sure to test your alkalinity and PH levels on a regular bases. Once your alkalinity
begins to drop below 80 ppm, the conditions for a PH crash are possible and fatality to fish will begin. Usage of Baking soda is a regular practice in maintaining alkalinity levels. Since alkalinity is the buffer to PH, be sure to watch and keep the alkalinity levels up. Increasing more then 25 ppm per day may cause stress to the fish. Consider dissolving the Baking Soda (100% Sodium Bicarbonate) with some water and pour around the pond, or pour the powder in a separate area of your pond like a stream, skimmer or pre-filter. If your water has high levels of alkalinity, then your regular water changes may be enough to help maintain your alkalinity and PH. In either case, testing regularly will help in keeping good water quality.

Creating the Cycle. Begin with water conditions tested to be in normal ranges (Alk. PH.). Normally it takes a minimum of 21 or more days to cycle once Ammonia is present in the water. Complete Cycling can take 4-6 weeks. 5 to 7 days is possible by spiking a new filtering system using bio-filter
media containing bacteria from an existing filtering system. Two methods to consider for getting Ammonia to exist.

* Adding 100% Clear Ammonia (Check at Rite Aid)
* Adding some fish (Expendable Gold or Koi fish)

When adding clear Ammonia, be sure that it does not contain any soap. Add 9 teaspoons of Ammonia for every 100 gallons of water. The Ammonia level should be around 5 ppm when tested. Maintain reasonably warm and well oxygenated water (65+) flowing through your filtering system. DO NOT ADD FISH while using this method! Wait till the your nitrite tests
indicate 0 ppm. The disadvantage to this method is that it does take 3 weeks before the Ammonia level reaches 0 ppm and the water color will turn a tea color. Water changes after the 5th week will begin to reduce the tea color. Since nitrite is the byproduct of the good bacteria called "Nitrosomonas", nitrite levels will begin to increase 7-16 days after the addition of Ammonia. DO NOT ADD ANY FISH UNTIL the Nitrite levels reach ZERO! Then follow up with regular testing weekly of all tests. PH, Alkalinity, Ammonia, Nitrite, and Nitrate.

When creating a cycled filtering system using the method of adding fish, use only a few fish and don't over feed! Be sure the fish are expendable and not too valuable to you. In case they become ill and die from the toxicity of Ammonia and or Nitrites. It would be a very wise thing to test everyday for until the Ammonia and Nitrites reach 0. Then follow up with regular testing weekly of all tests. PH, Alkalinity, Ammonia, Nitrite, and Nitrate.

The best and most ideal way to cycle a new filtering system is to use some filter media from an existing and cycled pond bio-filter. Placing some of this media in the filter or in a location that permits the water to flow over it will begin to introduce the good bacteria's into the new environment enabling the cycle process to reach a working level much faster then if you started from scratch. It is possible to be cycled in 3 to 7 days depending on how much media is introduced and other conditions. You may have fish in the environment during this time and it would be a very wise thing to test everyday for until the Ammonia and Nitrites reach 0. Then follow up with regular testing weekly of all tests. PH, Alkalinity, Ammonia, Nitrite, and Nitrate.

Salt. The cheapest first consideration for treating a sick fish is to use Salt. Salt can be found at hardware stores for around $6.00 for a 40lb. bag. It eliminates 7 of the 9 parasites very quickly. And it will not harm your filtering system.
Bring the Salt content to 0.3% over a 3 day period by adding one lb.of salt for every 100 gallons each day. In the case of really ill fish, this can be done every 12 hours until the 0.3% range is reached. To recap; 3 lbs. added to 100 gallons = 0.3% salt.

Salt at 0.3% according to many sources will kill the following
* Ich. (Ichthyophthirus) White spots.
* Flukes
* North American Trichodina
* Costia
* Chilodinella
* Epistylis
* Scyphidia
* Glossatella

Protective coating. Salt stimulates the mucus slim coat over the outside of the Koi and benefits them in providing a protective coating from parasites.

Type of Salt to use. Non iodized, kosher, ice cream and sea salt are ok. Solar rock salt from a common hardware store is great. Be sure to read labels looking for 95.5% pure salt. Verify that the label does NOT list YPS or Yellow Prussiate of soda. Max Levels. Some have raised salt levels to 0.45% or even as high as 0.6%. The 0.6% should only be considered after doing more research and when attempting to kill Japanese Trichodina.

Adding the salt. Since the quickest way to dissolve salt is to locate it in the path of moving water, consider adding it in a stream bed or waterfall. Adding to the pre-filter or skimmer will work, yet may kill off some of the beneficial bacteria in the bio-filter since this will be a very strong dose. For smaller ponds, add the rock salt to a sock and lay it on the waterfall. Usage of a towel to form a sack or consider folding a couple of layers of some netting to form a sack and then lay this sack containing your salt in the path of moving water.

Plants. Also remember that salt levels do harm some plants. Most plants can handle 0.1%. At 0.3%, hardy water lilies, Irises or common papyrus are ok. Water Hyacinths, Lettuce and celery will yellow.

If you are treating ill Koi: A Koi fish immune system is not active unless the water is 55 degrees or higher. When quarantining an ill fish in a another tank, it is recommended to use some of the water that they were in and began to warm it slowly over days. A sudden change of temp., chemicals, or being chased when catching can be enough stress to send this fish over the edge. Koi Fish naturally have a 1.0% salt level. By adding salt, the buoyancy of a Koi reaches closer to a neutral level and the Koi can swim with less effort. This less amount of stress to an ill fish also benefits them from less water pressure on infected or open wounds. Once you begin increasing the salt level, you may see more activity from your Koi.

How long does salt remain? Salt stays in the pond until you remove water. Salt does NOT evaporate! You should NOT keep 0.3% salt level in your pond year round. This practice will only develop tougher trains of parasites. When this happens, you may not be able to help your fish
with salt.

Salting to the seasons. Some increase salt levels in the fall and then lower the percentage during the winter water changes. Then increase again going into spring, then reduce during the summer water changes. This does several things. Twice a year you are killing off possible
parasites and are increasing the protective slim coats. This may not be for everyone since keeping plants in the pond are effected. Others may resort to use of chemicals for treating the pond seasonally or when ill fish warrant treatment.

Biological Filtration Media. The bacteria that converts harmful nitrogen by products from aquatic animals into less harmful nitrates occurs naturally in nature's lakes and streams. In a koi pond these bacteria are found on the walls of our ponds. They also can be found on the inside walls of the pond plumbing, attached to the skimmer basket, and on the rocks that form a waterfall. The reason we build biological filter systems is to increase the available surface area for these bacteria to colonize. Rock is an economical and the most common media used in pond filters. Because of rock's low cost and availability, it is a good material to use for a biological filter media. But rock or crushed gravel is not the only material that can be used as a filter media. Any material that bacteria can attach to is suitable for a filter media. Before we discuss an alternate to using rock, lets review some beliefs koi people have about rock.

When I started in the koi hobby, the message I got concerning using rock for biological filter media was; The best rock was roofing rock. The recommended brand was Sunshine Rock. Sunshine roofing rock is crushed granite gravel about half the size of pea gravel. It is used as a topping on asphalt and felt commercial building roofs, and is available in Southern California in 100 lb. bags from roofing supply outlets. The reason given for using roofing rock was that the smaller the rock, the greater the surface area. It was also said that crushed rock was preferable over smooth river rock. The reason was the crushed rock provides more "nooks and crannies" for the bacteria to live than smooth river rock. Pea gravel was ok, as long as it was crushed pea gravel. Roofing rock was said to be better. Sand was too small. Sand would clog and then the water would "channel" and this would defeat the advantage of the smaller size equals greater surface area belief. This seemed to make sense and the roofing rock worked just fine. In addition, I obtained a copy of the revered book on filtration by Stephen Spotte, Fish and Invertebrate Culture, Water Management in Closed Systems, 1970, John Wiley & Sons. New York. In Spotte's book he says "the best size is 2 - 5 mm". This supported the Sunshine rock. Another rock method being touted was the layering method. The layering method was a layer of 2" rock, with a layer of pea gravel, and with a layer of coarse #12 sand on top. I might add that there was some filter debate concerning in pond vs out of pond filters and up-flow vs down-flow, with the out of pond, up-flow filter as generally the winner. The bottom line here in Southern California was (and still is), any method was right if it kept your water clear and your fish healthy.

Back in the late seventies and early eighties I had the opportunity to visit many private koi ponds. I got to see filter systems that worked and many that did not work or were inefficient. Also had the opportunity and luck to run into a goldfish and koi hobbyist (backyard breeder) who was totally disassociated with any koi clubs or connection to A.K.C.A. This lady had several above ground ponds with out of pond "sideway-flow" biological filters. For rock she used the decorative white 1- 1 1/2" rock used in landscaping. When I asked her about her unusual filters and I tried to "educate" her about filter construction, she informed me that she had come to this design after many years of experience and trial and error. And besides it worked for her!

My own experiences taught me that roofing rock and crushed pea gravel worked great but eventually after a couple of years it got harder and harder to keep it clean. My experience also taught me that in the beginning when the rock was new, it probably worked because of all the massive surface area it provided. Towards the second year, the filter rock became fully established, and the filter worked better. By established I mean that the bacteria count has reached its maximum. And the nooks and crannies between the rock contain "detritus" which greatly improves the filtering capacity of the filter. Eventually the filter performance would gradually deteriorate, partly because of the increase in fish load do to the growing fish and partly because it was getting harder and harder to keep the rock from clogging. An air cleaning system help immensely, but I always skimped on settling basins. Eventually I would have to remove all, or part of the rock in stages, and clean it by rinsing it off in a box with a wire screen bottom. If I replaced the gravel with crushed 3/4 rock it did not seem to decrease the filter's performance.

Then along came Grant Fujita's book Nishikigoi (republished as KOI by A.K.C.A.). In this book Grant talks about the advantages of using 2" smooth rock. Previously Grant had introduced the New Marine pressurized biological filter. In addition, we now have brushes, fiber mat, open cell foam, and spirorex being used as a biological filter media. In addition, we have borrowed from the salt water aquarium hobby, plastic filter media.

What does it all mean? The bottom line is, you must have some type of biological filter. Contrary to what some people believe, you do not have to have a mechanical sand or fine filtering media to keep a well stocked koi pond's water crystal clear. Did I mention that my koi ponds have clear water and get some full direct sun? Filter size and system design are more important. The filter media can be any of the above mentioned.

Types of Filters (Some)

Trickle towers have been found to be the most optimal bio-filter design of filtering since there design adds the additional important element needed, oxygen. The water splashes over the media adding oxygen and cleansing decaying bacteria. Since the trickle tower design tends to be high or tower like in design, many look for lower profile bio-filtration type designs. Trickle towers are used by some successful Japanese Koi farms in Japan. For smaller ponds, Quarantine tanks or other small applications, consider the Tetra Filter.

Bead filters have proven to be ideal in being able to keep a low profile and achieve many benefits to the beginning, average or experienced Koi Keeper. Bead filters are capable of sizing to the demand required and be done with the least amount of ease and maintenance. The Advantage bead filter really is very simple to use and requires very little cleaning when compared to other filter systems. Consider the Advantage Filter.

Barrel Media filters have long been a favorite for pond keepers since they are the easiest to design and are great for the do it yourselfer (DYI). They are capable of housing plenty of bacteria and can be designed so many ways for so many different needs to fit the end users needs or requirements. Matting material is probably the most popular media used to date and can be cut to fit any design. While many other new forms of media continue to reach the market place, they all have there advantages and disadvantages and this may require some research to make any final decisions when building such a filter. Anything from plastic tubs to 55 gallon drums are used. The disadvantage to barrel filters is messy cleaning process.

Underwater Gravel filters are popular among some Koi Pond keepers. Simulating that design of aquariums that pass water down through a gravel layer. The water then returns up via plumbing. To build the lower return system, many use a network of PVC tubing that has many "T"s or PVC branch lines which are slotted to permit water to enter and not the gravel. This framework is laid out along the bottom and 4 to 6 inches of gravel is poured over. The gravel acts as the mechanical and bio filter because crud is trapped and the Bacteria grow on the gravel. The maintenance of this method requires rigorous stirring of the gravel from time to time to break up the crud lying down deep in the gravel. Different methods are used to clean this type of filter. One method of cleaning first requires users to stir up the gravel while a second tube then pulls the dirty water out and runs it through a mechanical filter to trap the crud before it returns to the pond. If the gravel is not occasionally cleaned of the trapped crud, like any filter, the crud eventually goes anaerobic and releases a toxic gas.

Sand Filter Another popular choice by some. The sand is capable of having more surface area for hosting good bacteria. Conventional sand filters have proven for years to give incredible water clarity. While this may be up the side, they are know for clogging problems and are capable of channeling the water. When this happens, the filter is not running in a state of efficiency and requires deeper and messier cleaning to break up the sand and crud to get the filter clean. This may have been the reason why bead filters have become so popular.

Glass Filter A recycled glass media is used instead of sand. This new material is 20% lighter than sand which makes it easier to clean during the backwash cycle. Additionally, because of the irregular shape of the glass media it is not prone to “channeling” like sand will. It works similarly to a conventional sand filter, which have proven for years to give incredible water clarity except, without the clogging problems associated with a sand filter.

Although the Advantage Bead Filter will give you exceptionally clear water, this Glass filter takes it to a higher level. "This filter is designed to be placed after the Advantage Bead Filter." Most peoples comments are "The water is so clear, the fish look like they are floating through air!"

Advantage Glass Filter - Read More

Water Changes. Water changes are necessary. In natures design, she provides the occasional influx of rain and water shed. Some of which arrives from streams bringing with it fresh minerals. Normally, water and toxins are able to seep or penetrate the pond or lakes bottom. Our liners or cement bottoms create a barrier preventing this. To duplicate natures water changes requires draining off a percentage of water. Then make any needed adjustments in the chemistry of calcium, alkalinity and PH. Performing water changes is the final act of benefiting your ponds water quality and filtering needs. Existing pond water is teaming with life and is often referred to as living water. Rarely is it needed to drain off more then 50% of the water. The max to drain off should never be more then75%. Maintenance water changes are 5% weekly or 10% by weekly. The 5% weekly is considered less stressful for fish.

When adding water that contains ANY Chlorine, add the Dechlorinator to the pond first.

Large Pond Filtering

Building a small lake? Filtering mechanically and biologically of large ponds or lakes 40,000 to 400,000 gallons of water is not similar to that of common smaller ponds. It just would not be cost prohibitive. Once your volume of water falls in the above parameters, then consider using nature’s own engineering to maintain clarity. Enhancing circulation and aeration as much as possible can do this.

Ever notice golf course ponds. You’re not likely to find a bio filtering system. Instead, you’ll see quit often, some type of fountain or bubbler like fountain. The fountains they use are pulling large volumes of water up from the bottom and forcing it up and out towards the edges of the pond or lake. This large movement of water is getting aeration as it is forced up and out. Second, it is accomplishing total pond circulation. As the water moves towards the edges, it is then drawn down across the bottom to be pulled up again by the fountain. The larger the pond, the more fountains are required to achieve total circulation. For ponds that are longer, then install them centered in several locations the length of the pond. This massive amount of aeration and circulation enhances the biological bacteria to maintain a healthy pond. Stagnate water is created by the very lack of water movement and aeration.

As for the different types of fountains, consider the following model as a reasonably priced and good quality unit. Call to order.

1 Strata-Flo Floating Aeration Pump Assembly.

1 – ½ hp Strata-Flo
300’ cord, 6/3 wiring, 115v, Hibiscus Nozzle

The nice part about using a fountain: No backwashing like regular bio-filters…

Strata-Flo with Hibiscus Nozzle

Spray: 3’ up, 5’ out

Perfect for golf courses, parks and retention ponds.

Strata-flo™…the solution to your pond management headaches. The Strata-flo’s™ high-flow, propeller driven output means algae, unpleasant odors, sludge, weeds and poor water clarity due to stratification are history, without the need for chemicals, dyes or labor-intensive dredging. The Strata-flo™ pumping system aerates colder, denser water from deep below in a beautiful, changeable fountain display that re-oxygenates and de-stratifies water layers, aiding in the natural biodegradation of algae for clearer, healthier, more easily managed ponds.

Bio Filter Bucket - A simple Do It Yourself - DIY filter

Building your own bio-filter is not too hard. For those that need a quick bio-filter, consider building this small 5 gallon filter that can use Lava Rock or most any other media. Important fact! - Lava rock if used should be replaced every year during the winter!!! Lava Rock has tiny pockets that do not get cleaned out and as the good nitrifying bacteria becomes trapped, it will become anaerobic and toxic. Don't let this keep you from using lava rock for this filter, just realize that you should throw it away after a year. This filter when completed will be above water level.

Water pump size - Recommend range 350 - 800 GPH, Max 1000 GPH.

How to: Take one CLEAN 5 gallon bucket, and drill 4 to 8, 1/2 inch holes close to the bottom. (1 inch or so off the bottom). Drill them all the way around if your going to set on a support in the pond. (Could set it on another inverted bucket) If you would like the water to only come out on one side because your planning on placing this filter on the ledge or side of the pond, then just drill the holes on the one side or even consider using a little larger drill bit. No drill has to be used if your safe with a sharp knife... More holes are needed if water is higher then 1.5 to 2 inches from the bottom, inside during operation. Important: Drill one more small hole close to the top in the side. This lets air in during operation.

Now place the CLEAN lava rock or other media in the bucket. Fill about 2/3 full. Snap on lid. Cut a hole in the center of the lid so that the entry water supply pipe stays snug. Water tight is not needed, just make the whole tight to help hold the water supply pipe tight in place. Then connect the water supply pipe to the pump.

If you have some media from an older filter, some of it if added inside this bucket will kick start the nitrification cycle much faster. Your new filter will be cycled in 3 to 7 days. Or, if your using older pond water, it too will help cycle the filter with good bacteria in 3 to 7 days. If you have nothing to help kick start this filter, then realize that it will take a full three weeks for the filter to cycle. Providing some ammonia is in the water. A few fish will provide this ammonia. If so, feed very little and test for ammonia everyday!

Slow way down on the feeding while waiting for the new filter to cycle. Also be testing for Ammonia. Be sure to have an Ammonia test kit on hand. If you detect higher then .05 levels, then perform a 10 to 25% water change. Be sure to treat the new water with a De-chlorinator.

This design is considered a "Trickle Tower". The benefits of a trickle tower are many. Oxygen is added as the water cascades over and through the lava rock or other media. Water passing over the media also washes away the aging nitrifying bacteria. Because of the design, larger colonies of nitrifying bacteria will be able to be present then that of a submerged bio-filter.

3 Barrel Filters - Settling, Pre-Filter and Aerated Bio-Filter

Using 55 gallon barrels work really well for making a filtration system. Keep in mind that the water level in the barrels will match that of the ponds elevation. So you may find yourself digging a large hole in the ground for the barrels unless your pond is build on a hill and the barrels are on the down hill side.

Matala rolled media works great in this design. The brushes as an option can be in the first barrel or the second. Consider trying both ways to see which provides clearer water. If you want to install a pond overflow, then the first barrel would be an ideal location by using another bulkhead and an elbow pointed up with a short section of PVC cut to the proper height. The use of aeration in the biological barrel can be considered as an option, yet having it in operation greatly improves the environment and performance of the beneficial bacteria.

Building your own barrel filter will require the following list of items. The barrels can found at your local car wash often for free to 5 or $10 each. Rinse them several times to remove soap. Connect all three bottom waste lines to a single line. The reason the bulkheads for the waste lines are not centered through the bottom is because the 55 gal. barrels typically have a ridge seam through the center of the bottom which will not permit a flat surface for the bulkheads to seal. Cement is used to shape the inside bottom.

Important note: The flow rate through the barrels. Pump no more then 1800 gallons per hour to permit enough time for the crud to settle in the 1st barrel. (55 gal. drum - 22" dia.)

Water pumps for ponds.You want a pump that delivers the maximum volume but at the lowest possible Running Cost! The two are NOT the same. When it comes to good Koi pond design a non pressurised filtration system will Always be cheaper to run - because your pump does not have to pump against the resistance that any pressurised system faces. Pumping against this resistance uses energy (in this case electricity) for which you pay. Same thing applies to very high water features. Getting the water up there uses a lot of energy and your pump will cost you more to run as you will need a pump that can deliver enough energy to the job at hand. Bear in mind that a pump uses a fixed amount of energy. Whether it runs at full tilt, or whether you throttle it back with a valve the pump will consume the same number of watts.

Hence a 100 W pump will use 100 watts whether it pumps 1000 litres of water up a height of 1 meters or whether it pumps it up 6 meters. All that differs is the flowrate at the different heights - at 6m you will get dramatically less water than at 1 meter, if indeed you get any water at all!

So consider your pumps carefully. We like to use low power consumption pumps that deliver large volumes of water but are not as good as pushing water high up or through pressurised systems. There is always a trade off between the cost of running a pump and between high flow rates through pressurised or even non pressurised systems. Airpumps are the most overlooked components of a Koi pond.Which is a fairly bold thing to say... ! But it's true...So you have a venturi and three thousand water falls cascading several hundred metres into your Koi pond that is 600mm deep with 1000 square meters of surface area.

You must have saturated oxygen levels right...? Wrong..!

Getting water to dissolve oxygen is hard and difficult. In fact it is a lot of work. We've been saying it for years - your Koi pond can never have too much dissolved oxygen in it.

The Japanese know and understand this. They have been keeping Koi for centuries. And in every single Japanese Koi pond we have seen there is massive amounts of aeration. Venturis do NOT oxygenate Koi ponds. Waterfalls help, but should not be relied upon for oxygenation purposes. Oxygen diffuses into your Koi pond at the surface, where it slowly dissolves across the air/water interface. The operative word here is "slowly". The warmer the water the less oxygen it can carry and the longer it takes to dissolve - yet the more active the Koi are and the more oxygen they require!

The maximum level of dissolved oxygen that water can carry is only theoretical and can perhaps be achieved in a laboratory under controlled conditions. Anyone who tells you that their water in their Koi pond (that actually contains some Koi) is at oxygen saturation is talking utter rubbish plain and simple. Even if their test kit backs them up it serves to prove that the test kit isn't worth its weight in dog turds.

It is physically impossible to achieve oxygen saturation in a Koi pond. The absolute best that you can hope for is to get as close as possible and within 80% would be exceptionally good. Oxygen is used in many processes - all of which have varying demand and hence the strain on the supply of oxygen varies considerably throughout the course of day and night. So, getting oxygen in via the water/air interface is the area we should be concentrating our efforts on. Water at the bottom of the pond is not going to get any oxygen unless it comes up into contact with the water/air interface. It is precisely this action that our air pumps deliver. By creating a plume of bubbles at the bottom of the pond, water is pulled up along with the bubbles as they surface, bringing deep water to the surface of the pond. This is called vertical circulation and it is this action that improves dissolved oxygen levels in a pond.

By bringing oxygen poor water from the depths into the air/water interface zone oxygen is given a chance to dissolve into oxygen poor water (which is much easier for the oxygen to do than if the water already contains a fair amount of oxygen). Compare this with a venturi that basically pushes all the surface water (which is likely to be oxygen rich anyway) around the top of the pond. This achieves the square root of nothing since the oxygen poor water lying underneath remains there -out of the elusive air/water interface zone.

A waterfall does the same thing. Some oxygen rich water hits the pond, but unless the water fall is very steep and amazingly high, this water is unlikely to penetrate to the depths where it is most needed! So you end up with the same problem. And no, just keeping the surface water well oxygenated is not enough, unless your pond is only 200mm deep... This is because no matter how much oxygen the surface water contains, it will not be enough when all your Koi decide that they need it for whatever reason. The reality is that the vast majority of ponds run under oxygen poor conditions. It's a very simple test to make. If there are air stones, or aerated bottom domes, or air curtains in a Koi pond it WILL be far, far better aerated and more oxygen rich than any other pond with waterfalls or venturis could ever hope for.

And that folks, is the bottom line. Air into your pond to create vertical circulation within the pond is a critical element to Koi pond success. Do not underestimate it!

Water (misc.)

1 cubic foot water = 7.48 gallons.

1 cubic foot water = 62.5 lbs.

1 gallon of water weighs 8.33 lbs.

1 GPM = 60 GPH

Double a pipe's diameter increases volume up to 4 times

BIOLOGICAL FILTRATION

2009-02-13T09:01:00.002+08:00

What is biological filtration?
Biological filtration is the use of beneficial bacteria to eliminate organic waste compounds from a body of water. It is distinguished from mechanical filtration, which is a process whereby water is strained and suspended material is physically removed from the water. The bacteria that do the work in a biological filter are part of the "nitrogen cycle," a series of events that also occurs in nature.

Why is it important?
By eliminating the organic waste compounds in the water, biological filtration detoxifies the water and makes it safe for fish. Additionally, by removing the organic waste compounds, algae is controlled because those compounds are the nutriment that algae require in order to grow.

What is a biological filter?
A biological filter or "bio filter" is simply a home for the beneficial bacteria that perform the nitrogen cycle. The filter provides surface area that the bacteria can live on and a recirculating water pump ensures that water is constantly flushing over the bacteria so they can obtain their necessary nutriment and oxygen.

Where do the bacteria come from?
The bacteria occur naturally in a pond. They live on fish and other underwater surfaces such as plant stems and rocks. In order to get the bacteria established in a filter or new environment, aquarium and pond owners used to borrow some gravel that had bacteria on it from an existing system. This cumbersome procedure is no longer necessary as there are now available bottled viable bacteria cultures in either living form or freeze dried spores.

If the bacteria occur naturally, why is a bio filter necessary?
Most backyard ponds have a much higher concentration of fish than would occur in nature, and the fish are usually fed a high-protein food. These facts result in a higher concentration of organic waste, i.e., ammonia,than the naturally occurring bacteria can deal with. A bio filter houses more bacteria, hopefully enough bacteria, so that ammonia and the other nitrogen compounds are completely eliminated.

Why do ponds turn green?
Ammonia is at the root of most green water (algae) problems. As discussed below, ammonia forms naturally in the pond and is toxic to fish. Ammonia may be eliminated by the beneficial bacteria in a properly operating bio filter, but if it is not, the pond could become toxic were it not for algae. Algae is nature's safety net for fish. If ammonia levels rise, algae will colonize the pond and make it safe for fish by taking up the ammonia as nutriment.

The Nitrogen Cycle
The nitrogen cycle consists of three basic steps; 1) ammonia to nitrite, 2) nitrite to nitrate, 3) nitrate to free nitrogen. Ammonia is created from two sources- fish and other animal waste, and decaying organic debris (leaf litter, pollen, etc.) that gets into the pond. To complicate matters, ammonia is present in two forms - free (NH3) which is very toxic to fish, and ionized(NH4-) which is still toxic but less so. The higher the pH, the greater the ratio of the more toxic free form to the ionized form. Nitrosomonas bacteria oxidize ammonia into nitrite by the addition of oxygen, and nitrobacter bacteria oxidize nitrite into nitrate. These two types of bacteria are referred to as "nitrifying bacteria," and live on surfaces in the pond, such as plant stems, rocks and even on the fish themselves. They require oxygen in order to live and to perform their function.

Nitrate is eliminated by "denitrifying bacteria" that live in the bottom mud. These mud dwellers are anaerobic bacteria that die in the presence of oxygen, and, as they do their work converting nitrate to free nitrogen, also release hydrogen sulfide and methane gases - the swamp smell. Most clean, well aerated backyard ponds do not have an anaerobic environment or chamber, and nitrate thus accumulates in the pond. It is nowhere near as toxic to fish as are ammonia and nitrite, but it is a nitrogen fertilizer and will encourage an algae bloom. Fortunately for beleaguered pond owners, there are now available proprietary formulations of bacteria that eliminate nitrate in the presence of oxygen. These bacteria can be added to the pond and thus allow the nitrogen cycle to be completed so that algae will not colonize the pond. Otherwise, plants, periodic partial water changes or algae must be relied upon to remove the nitrate.
Two types of biological filters

There are two basic types of bio filters; in-pond and out-of-pond. Out-of-pond filters are further divided into two types - pressurized and non-pressurized. In-pond filters are typically used in smaller ponds, say up to about 1500 gallons, and out-of-pond filters are typically used in larger ponds, although this rule is far from absolute. The main function of any type of bio filter (i.e. providing a home to bacteria ), is the same regardless of design. The differences are in cleaning, space requirements, and add-on enhancements.

An in-pond filter has a submersible pump attached, and all the equipment is in the pond. The advantages are ease of installation and cost economy. The disadvantage is that you have to reach into the pond to clean the filter. Some in-pond filters have only a sponge for the bacteria to live on and do not work very well because the bacteria are killed off every time the sponge is cleaned. Others, such as the Bio+Plus, have separate mechanical and biological chambers, and are much more efficient.

Out-of-pond non-pressurized systems are the oldest form of bio filter - a simple gravel bed. Usually the water is pumped into the filter below the gravel, with a gravity flow back to the pond, although with proper engineering the reverse can also be set up. Gravel bed filters are custom built at the pond site and are very difficult to clean unless expertly engineered.
Out-of-pond pressurized filters

Out-of-pond pressurized filters are typically swimming pool sand filters that are modified for pond use. (Diatomaceous earth and cartridge type swimming pool filters are generally not used in ponds, as they get clogged up too fast.) These filters have the advantage of being very easy to clean and, because the water is under pressure, are very flexible for variations installation requirements. A problem for the inexperienced installer is that all the instructions that come with these types of filters are for spas or swimming pools - not for ponds. Sizing of pump, canister, and medium are different for ponds, and only the side-mounted multiport valves provide a sufficient backwash. When they are sized and maintained properly, they provide excellent bio filtration.

What makes a pressurized filter so easy to maintain is the multiport valve that controls the flow of water through the filter. There are backwash and rinse positions that allow pond water to be used to clean the filter. The dirty water is discharged to waste, and the whole process only takes a minute or so. If the sand grain size is too small, however, back-washing will not be effective, and water will channelize through the filter, greatly reducing efficiency.
Set up and Maintenance

Since the primary purpose of a bio filter is to provide surface area for beneficial bacteria to live on, the size of the filter depends upon the amount of organic waste the bacteria have to deal with. The amount of waste is a function of the fish population, debris that blows in from nearby plants and trees and water plants such as water lilies that drop a lot of debris of their own. There's not much reason to have an over-sized bio filter,as the bacteria population will only be as large as the organic waste warrants. The exception to this rule is a poorly designed or hard-to-maintain filter that is inefficient and requires a larger surface area because the bacteria are struggling to survive.

In-pond-filter
The filter should be placed as far away from a waterfall or fountain as is practical. If the pond is deep, it may be set on blocks for easy access and cleaning. Typically, tubing runs from the discharge of the submersible pump that is attached to the filter to a waterfall or fountain. The water then circulates through the full range of the pond, and stagnant areas are avoided. If there is no waterfall or fountain, a venturi T should be added to the discharge tubing to ensure proper aeration.

Out-of-pond pressurized filter
Water is drawn from the pond, through the pump to the filter and then back to the pond. Typically a non-submersible pump is used that has sufficient power for proper back-washing. The water may be drawn from the pond through a surface skimmer, which helps considerably in maintaining good water quality.

PVC pipe, usually 1 1/2" or 2.0" depending on pipe length and pump size, is trenched from the pond to the pump, which is normally located next to the filter but need not be. However, since the pump must be shut off everytime the position of the multiport valve is changed, the on/off switch should be near the filter. There two discharge pipes from the filter; return-to-pond, and waste. The return-to-pond pipe may be T'd and valved so that water may return via the waterfall or through an underwater jet.

Fluidized-Bed Filters
Fluidized-bed filters are a very unique biological filter. If properly designed and built tall enough, they have the ability to cultivate not only aerobic nitrifying bacteria, but also facultative anaerobic denitrifying bacteria. This means they may have the capability to remove not only ammonia and nitrite, but also nitrates. They usually consist of some type of column chamber which houses several cups or more of coarse sand or similar media. Water enters at the bottom of the filter and exits at the top. There is usually a control valve for regulating water flow. A check valve is usually placed on the filter intake to prevent the sand from packing-down when the filter is turned off.

Because water flows upward through the filter, the sand in the filter becomes suspended or "fluidized" in the water column, forming a fluidized bed of sand. If the flow of water is controlled properly, the sand does not flow out of the filter, but remains suspended. This happens because the flow of water is just fast enough to keep the sand in suspension. The weight of the sand prevents it from escaping the filter. Because the sand is suspended in water, fluidized-bed filters are self cleaning, and require little or no maintenance.

The water at the bottom of the filter is fresh and high in dissolved oxygen, so aerobic bacteria cultivate in the bottom half of the sand bed, and remove ammonia and nitrite, using up oxygen in the process. In taller fluidized-bed filters, enough aerobic bacteria cultivate in the bottom half so that as water flows past them, they remove most of the oxygen from the water, so facultative anaerobic bacteria cultivate in the top half of the sand bed where they remove nitrates. Not all fluidized-bed filters are tall enough to promote anaerobic denitrifying bacteria, but most are very efficient at cultivating beneficial aerobic bacteria.

Some fluidized-bed filter designs are stand-alone units that are too tall to be placed under an aquarium in a cabinet stand. These are actually the best designs, but are not practical for most aquariums. Other fluidized-bed filters are designed to hang on the back of an aquarium or sit in a reservoir, and may be driven by a small pump or the return line of a canister filter. These types of fluidized-bed filters are an excellent way to provide biological filtration on an aquarium equipped only with a canister filter.

Plenum Systems
Describing a plenum requires far more than just a single paragraph. The plenum method was discovered by Dr. Jean Jaubert and is often referred to as the Jaubert System. "Plenum" refers to an un-oxygenated layer of water trapped beneath a deep layer of gravel or sand at the bottom of an aquarium. This layer of water becomes anaerobic. Bacteria cultivate in this oxygen-free environment and remove nitrates from the aquarium. There are several variations of the plenum, depending on what literature you read.

The basic structure of the plenum system is essentially a deep (3" to 4") layer of gravel, suspended 1/2" to 1" above the bottom of an aquarium. It is usually recommended that very little or no water flow should be directed across the gravel surface. A basic plenum may be created by suspending egg crate material or under gravel filter plates above the aquarium bottom, using inert supports such as PVC pipe. If egg crate is used, it is covered with nylon screening over which the deep gravel bed is placed. The actual materials, including what grade of gravel or sand is used, vary depending on what literature you read, but usually coarse live sand, fine coral gravel, or a combination of both are used. One technique is to use 2" of live sand on the bottom, over which nylon screening is placed. The screen is then covered by 2" of fine coral gravel. This allows the aquarist to turn over the top inch of gravel occasionally to clean it, without disturbing the anaerobic layer below.

Anaerobic bacteria form in the bottom depths of the substrate and in the water below. As anaerobic bacteria cultivate, they remove nitrates. Anaerobic action produces a fair amount of heat. The heat warms the water layer below the gravel. The warmer water flows upwards, displacing cooler water above the gravel. This action moves water through the plenum at very slow rates. The slow movement of water through the gravel helps to prevent dangerous hydrogen-sulfide gases from forming in the plenum. The deep gravel bed also provides a home for burrowing motile invertebrates which feed on solid organic mulm and detritus. These burrowing animals, which are either purchased and/or cultivate on their own from live rock, serve to keep the plenum porous and aid in the slow movement of water through the system. "Burrowing" sea cucumbers that serve this function well may be purchased from a good aquarium store.

The aquarium is stocked with live rock, but not as much as is typically used. The live rock construct should be suspended above the gravel bed, allowing water to move freely beneath the reef. This may be accomplished in a number of ways. One way is to place a couple of "anchor" pieces on the gravel bed, and glue others to the back of the tank using aquarium epoxy putty (not silicone!). The rest of the live rock may then be bridged across these supports to build the reef, but not too high. The construct should be loose, not tightly packed together, to allow good flow through the rock. Care should be taken not to direct flow from pump returns across the gravel. The emphasis in aquariums using a plenum should be on the reef, with a minimal number of fish to balance the ecology.

The Jaubert Plenum System, if constructed properly, can work well, provided the aquarium is only lightly-stocked with fish. While we are sure some hobbyists would disagree with us here, we feel that more research is necessary on this fascinating subject. The original plenum method used aeration as the only means of water movement in the tank. We highly recommend that a plenum be used in conjunction with a Berlin system. The protein skimmer will remove other dissolved and solid organics, not removed by the plenum. The use of a protein skimmer combined with the plenum method may be the key to keeping more fish while using this type of biological filtration. If you're setting up a new aquarium, installing a plenum will be relatively easy. If you have an existing reef tank, installing a plenum will involve a fair to major amount of work. Definitely read up on the subject before you go to work.

Pumps
The rule of thumb is to pump the volume of the pond through the filter once an hour, with a higher turnover rate for small ponds (say, under 500 gallons) and a lower rate okay for larger ponds (say, over 2500 gallons). The pump must operate 24 hours a day in order to keep the bacteria alive. It is much better to have a smaller pump that is cheaper to operate running all the time than to have a larger pump that is shut off part of the day.
Sometimes a two-speed pump makes a lot of sense. It runs on low all the time to save energy costs and on high for back-washing or when a major water flow is desired. The new electromagnetic submersible pumps draw about one-seventh the energy of that of a similarly sized conventional pump, but they are limited in size.

What can go wrong?
If the bacteria colony is not thriving, ammonia will accumulate and algae will colonize the pond. The most common problems with bio filters (beyond poor design) are shutting off the pump for part of the day, improper cleaning, chlorine or chloramine in the water supply and copper leaching into the water from copper pipes. As previously noted, the pump must operate 24 hours a day. If the water source has chlorine or chloramine added, it can not be used to clean the filter as it will kill the bacteria. Furthermore, a chemical detoxifier must be added to the pond in an amount sufficient to treat new water added for topping up. If copper is present, it too must be detoxified with a proprietary water conditioner.

Both nitrifying and denitrifying bacteria should be added on a regular basis.

The sand in a pressurized filter should be checked after backwashing to ensure that it is clean. If not, a larger grain may be required.

Aquaculture Manual - Resources

2009-02-01T11:28:00.004+08:00

FISH FOODS
Some fish are fussy eaters; most fish will eat a wide range of foods, while a few will try just about anything. Garbage in, garbage out is as true for fish as for humans, but determining exactly what is garbage for a fish is slightly more difficult than human nutrition. Fish grow faster when there is a lot of protein in their diet, although they need their carbohydrates and vitamins as well. A good food to start with (and an excellent back-up food in any case) is any sort of cheap dog food or trout/catfish chow if you can get it. Another good all around food for fish is seaweed or kelp meal. This is especially good for baby fish and can be purchased at garden centers or feed mills.

Feeding ideas
1. Fertilization. If you are raising a herbivorous fish, or if the fish you are raisin cats something that grows readily in your system then fertilizing the tank to promote algal (and therefore zooplankton) growth. Compost is probably the best sort of fertilizer for a small system. Use only a handful or two and then wait to see what happens.
2. Food scraps. There are a lot of wasted foods out there, and if you can get your hands on a steady, local supply, you could end up feeding your fish for free. Tilapia will cat vegetable peelings, as will carp. Many fish will take meat scraps, fishmeal, or leftovers from the table. There are recipes available for homemade fish feeds from waste materials .

Here are some suggestions of food resources in the city.
Stale bread and bakery throwouts
Fish scraps - frozen and ground
Meat scraps - fresh or frozen and ground
Vegetable peelings
Old vegetables from markets
Restaurant wet wastes
These can be found at numerous commercial businesses, as well as public places like schools and institutions. If your fish will cat it, you probably produce enough food scraps 'in your house to feed a healthy population of tilapia. A tank full of leftover-eating fish can be your substitute.
3. Collect invertebrates for food. Most fish love eating insects, especially live ones, - and if you know where to look and are not too squeamish, there are lots of potential insect sources in and around a city. The first one that comes to my mind is cockroaches squish 'em and toss them to the sharks! Many of these can be trapped and (for the intrepid) can even be cultured right in your own backyard. Here are some ideas.
Earthworms
Cockroaches
Crickets
Snails
Slugs
Flies
Moths
Beetles
Buried beetle and wasp larvae
Big, juicy caterpillars
4. Keep a worm bin. Red wigglers are a favorite food of tilapia and also help you reduce your household wet wastes into nice, indoor compost. God's Gang, who have several aquacultural ecosystems set up in Chicago, grows red wigglers both for sale and to feed to their fish. Fish fed with earthworms on a regular basis grow healthy and strong due to the high vitamin content of these little guys.
5. Grow some plants. Fish, especially herbivorous fish, will eat a lot of plant materials that we do not even consider to be food, Of course, fish will eat just about all the fruits and vegetables that we eat, so these are not listed here but are also good sources of food. The following list shows some of the more exotic parts of the fish diet.
Water hyacinth - fish will not eat it unless you take it out of the tank, chop it up, and then return it to the tank
Azolla
Duckweed
Carrot tops
Marigolds
Taro leaves
Purslane
Green tomatoes
Much has been written on feeding fish and the references in the bibliography should give you some direction if you are interested in developing new ways of feeding them. Fish will eat so many things that it is always worth trying something new The best way to test a new food is to put a little bit in the tank and watch for awhile. Usually fish will mouth the new food and then spit it out - it is their way of testing. If they do not eat it right away, leave them alone for an hour or so and check again. The food will most likely be gone by then if they are going to eat it at all. An exception is live foods. Fish seem to know that a live insect or worm will stay fresh until they eat it (or until it dies), so they often let it live in the tank for a few days before consuming it. This is especially true with worms, who can live underwater if the water is well oxygenated. Just as they think that they have escaped, the fish usually eats them!

FISH SPECIES FOR AQUACULTURAL ECOSYSTEMS
I am not an expert in raising many different types of fish, but there are so many experts out there already that you can easily find information about the fish you might want to raise. Table 7-1 lists several fish species, their temperature ranges, and whether or not they are easy to raise. The last category was determined from a literature review generally aquaculture authors agree about which species are easy and which are temperamental. It is interesting to note that many widely farmed fish are actually quite difficult to raise. The reason that they are widely farmed usually has nothing to do with how easy or hard they are to raise, but rather how much money they can make for the farmer, and
that is why trout and channel catfish are so popular among North American farmers. In countries where people raise fish for their own or local consumption, carp, Chinese carp, and tilapia are much more widely raised.
Good places to go for advice about fish are extension agents, pet stores, fish dealers, and the library. Anybody who sells you fingerlings must know a thing or two about how to raise fish, so make sure that some advice is included in the purchase price. Take advice with a lot of salt, however. I cannot remember how many people have told me that I was raising fish the wrong way! Usually commercial fish farmers have little knowledge about recirculating systems but they still know a lot about the particular species of fish that they raise.

OTHER EDIBLE ANIMALS
There are several other species of animal, mostly invertebrate, that you might want to try raising as you become proficient. Most of these are crustaceans, but
if you like to eat frogs, why not? All these species are freshwater types and would be suitable for aquacultural ecosystems, providing you do a little background research on their natural history-
Freshwater shrimp (Macrobrachium spp.)
Crayfish (Procambarus spp.)
Bullfrog (Rana catesbeiana)
Freshwater clams
Turtles
Yabbles (an Australian crayfish)
Giant snail (Achanita spp.)
Escargot (Helix spp.)
Freshwater crab (Halicarcinus spp.)

VEGETABLES
These are lists of vegetables (including herbs and annual fruits) that grow well under certain conditions or are tolerant of aquatic conditions. Some of the uncommon ones may be difficult to get a hold of in North America but are included here, as you should be able to find them if you look hard enough. Also, some root vegetables have been largely overlooked as they are difficult (or at least impractical) to grow in aquacultural ecosystems.
Vegetables that float on the water surface
Water hyacinth
Water mimosa
Watercress
Vegetables that grow in underwater soil (emergent vegetables)
Water chestnut
Lotus
Taro (Colocasla esculentes)
Kangkong (Ipormea aquatica)
Watercress
Indian water chestnut
Arrowhead
Chinese arrowhead
Wild rice
Duck potato
Water celery
Manchurian wild rice
Vegetables that grow well in hydroponics
These are the basic ones. Almost all-common annual vegetables can be grown hydroponically with the exception of some root vegetables such as potatoes. See a good magazine like The Growing Edge or look in the bibliography for books about hydroponics.
Basil eggplant
Mint kale
Arugula lettuce
Chives mustard greens
Coriander peas
Ginger peppers
Parsley radish
Beans rapini
Bok choy spinach
Broccoli sweet potato
Cabbage tomato
Chard zucchini
Chinese cabbage cucumber
Corn

AQUATIC PLANTS
There are many aquatic plants available both in a good garden center as well as in the local pond. Increasing the diversity of aquatic plants in your system will also increase the diversity of the microorganisms that use aquatic plants as habitat. Many of them can be quite beautiful, especially if the conditions are right for them to flower. Also see the vegetable section for plants in these categories.
Floating plants
Water hyacinth
Water lettuce
Duck-weed
Salvinia
Azolla
Indonesian water hyacinth bladderwort
Submerged plants
Hydrilla
Elodea
Plants that are rooted in underwater soil (emergent plants)
Cattail
Alligatorweed
Pickerel weed
Smartweed
Lotus
Water lily
Water buttercup
Watercress

TROUBLESHOOTING
If you maintain a healthy system and do riot overload it with organisms, you should not encounter any serious problems. Every, system is different and therefore each system will experience problems in a different way. What I have tried to do here is to set up a problem-solving helper based on my experience of what some of the common problems are. If you come to the end of this helper and the problem is not solved then it is up to you - be resourceful!
To use this helper, simply look down the list of problems until you find one that sounds like what you are experiencing. There are numbers for solutions listed below. Sometimes a major problem (like Fish almost Dead) will refer you to a lesser problem (such as Pump is Broken) as problems seem to set themselves up in a hierarchy. Check each of these possible solutions in order to see I if they solve your problem. Good luck!

PROBLEMS
System problems
(P1) - Water is not circulating / no bubbles. (S1) (S2) (S3) (S4) (S5) (S6)
(P2) - Puddles on the floor around the system. (S7) (S15) (P4)
(P3) - Big puddle surrounding the system. (S8) (P9) (S15) (S17)
(P4) - Found a leak! (S9) (S15)
(P5) - Funny smell - rotten eggs. (S10)
(P6) - Funny smell - like manure. (S11)
(P7) - Funny smell - fishy smelling. (S12) (P11)
(P8) - Funny smell - ammonia! (S13) (S12)
(P9) - Cracks in the ceiling in room below system. (S14)

Fish problems
(P10) - ALL THE FISH ARE DEAD THIS MORNING! (P1) (P5) (P6) (P7) (P8) (S16) (S17)
(P11) - One of the fish is dead, others appear fine. (S18)
(P12) - Fish gasping at surface. (P5) (P6) (P7) (P8) (S19)
(P13) - One fish is swimming funny, covered with lesions, or does not feed with the rest. (S18)
(P14) - Fish attacking each other. (S22) (S23) (S24) (S16) (P5) (P6) (P7) (P8)
(P15)- Some fish seem to be missing. (S7) (S17) (S6) (S25)
(P16)- One fish grows really fast, smaller fish missing. (S26) (S25) (S6)
(P17) - Fish do not seem to grow (SI6) (S27)
(P18) - Fish never get very big, more and more appearing. (S27) (S24) (S16) (S28)
(P20)- Fish are not feeding. (S27) (P1)
Plant problems
(P21) - Plants appear unhealthy. (S30) (S31) (S32) (S33) (P26)
(P22) - Plants do not grow. (S31) (P21)
(P23) - Plants grow but are spindly. (S31) (P21)
(P24) - Plants grow well, but no flowers or fruits. (S30) (S31)
(P25) - Flowers appear, but no fruits. (S35) (S31)
(P26) - Insects, insects, everywhere! (S34)

SOLUTIONS
(S1) - Screens are clogged. These need regular maintenance for smooth operation. Scrub with a brush to remove accumulated algae and debris. If possible, use a larger mesh size.
(S2) - Air pump broken or not plugged in. Check for air from the outlet tube. If there is none then you may have blown a gasket. Buy a replacement gasket (US $2-3) at a pet store.
(S3) - Air tubing is clogged. Remove the air stone and try to blow through the tubing with your mouth - you should be able to do this easily and feel air coming out the other end.
(S4) - Air stone clogged. Air stones get clogged eventually with algae and other stuff They can be cleaned somewhat by soaking 'in vinegar, but will never bubble as well as a new one. Clean or replace.
(S5) - There is a clog in the plumbing. Visually inspect all plumbing, use a stick to probe the depths. Sometimes, a fish gets caught in the
plumbing and blocks it up. Snails will sometimes congregate in plumbing to the extent where water flow is blocked. Exclude both with some 1/4" mesh. (S6)
(S6) - There is a clog in the b1ofilter. If you make your biofilter too fine, or you do not use a large enough uptake pipe, you may find that your system clogs. Also, your biofilter may need a good cleaning. Set aside a few hours and take apart your b1ofiltcr to find out what the problem is. (S25)
(S7) - Fish like to play. Sometimes newly introduced fish splash around while they settle into their new environment. Sometimes they jump to their death. Put a net over the fish tank to prevent jumpers.
(S8) - There is a big leak in your system and you had better find it soon. Rescue what you can and try to determine if the leak is repairable. Usually a leak is found at a joint or in the biofilter - check those first.
(S9) - If you can, drain the System to below the level of the leak, let it dry out, and then repair with silicon. It is almost impossible to properly repair a leak while it is wet. Alternate layers of plastic bags and duct tape may do the trick, temporarily.
(S10) - Toxic hydrogen sulfide is being released! Act fast; provide as much dissolved oxygen as you can to the afflicted tank. Gently vacuum up any anaerobically decomposing material from the bottom of the tank. (P1)
(S11) Methane is being produced. Eventually, this can cause problems, especially if other people have to around your system. Gently vacuum up
any anaerobically decomposing material from the bottom of the tank. (P1)
(S12) - Food is rotting in the system. Locate and remove any obviously rotting pieces of food. Avoid feeding too much.
(S13) - Ammonia is highly toxic, aerate immediately Prevent future problems by encouraging nitrifying bacteria in a biofilter. (P1)
(S14) Call an engineer. Your system is too heavy for the building structure -move it to the basement.
(S15) - Leaking water can cause rotting problems with wooden structures. Protect the floor with plastic or move the system.
(S16) - Check the water temperature and compare it with recommended ranges for your fish.
(S17) Fish tanks in semi-public places are prone to vandalism. Respond appropriately.
(S18) - Remove fish and inspect for signs of disease or attack. Suspicious spots, missing scales, funny colored eyes, and other symptoms all could indicate a diseased fish. Alive still - S (20). Dead - S (21).
(S19) - Dissolved oxygen is in short supply. Aerate immediately by whatever means necessary. (P1)
(S20) - Keep fish isolated in a well-aerated tank. Feed only sparingly and only if fish seems willing to eat. (S21)
(S21) - Increase aeration and keep a close eye on the rest of the fish.
Consult a fish disease handbook and do a biopsy if you feel up to it.
(S22) - The attacked fish may be ill. See (S18).
(S23) - The attacking fish may be ill. See (S 18).
(S24) - The fish may be breeding. Consult natural history information about that species in order to confirm this.
(S25) - Sometimes fish escape into other parts of the system. If they have you will find them eventually.
(S26) - Fish are eating each other. Either come to terms with this horrible fact of life, or choose a less cannibalistic species. Increasing the availability of live food and reducing population density will reduce cannibalism. You could also try removing all the big fish, or removing all the small fish (called "grading").
(S27)- There may be a problem with the foods you are giving them. Try something different for awhile to see if they improve.
(S28)- Fish may be overcrowded. Increase water circulation and biofiltration or reduce fish density.
(S30)- There is a nutrient deficiency. Check a nutrient table to see if one of these matches the symptoms. Nutrient tables can be found in good gardening books.
(S31)- There is not enough light. Move the plants to a place where they can get more light, supplement the available light, or grow more shade-tolerant plants.
(S32)- The plants are diseased. Check a plant disease book. Remove and destroy diseased plants.
(S33)- The roots are waterlogged and possible rotting. Evaluate your growing system and consult the hydroponics literature.
(S34)- The plants may be infested with detrimental insects. Confirm with an insect guidebook. Feed infested plants (insects included) to the fish. Look in a good organic gardening book for ideas about controlling future
infestations.
(S35) There are no pollinators. Open the window or, if it is too cold, investigate artificial pollination techniques.

BIBLIOGRAPHY
Books and Manuals
I have in my opinions on the following books, which I have found useful for understanding and learning about aquaculture, hydroponics, and agriculture in general. Usually, the most interesting materials are in magazines and journals, but there is a lot of historical, reference, and background material in larger books. Older books tend to be interesting and informative - often they contain ideas that were rejected for one or another reason by the rather narrowly focused aquaculture/hydroponic industry. Much early work on sustainable and organic methods in these fields was rejected outright or modified by the industry to conform to sterile, chemical agriculture. Now, as sustainable aquaculture and organic hydroponics arc coming into vogue, many of the best books are out of print. A good public library can be a gold mine of useful information from the past.
Chakroff, Marilyn. 1976. Fresh water fish pond culture and management. Volunteers in Technical Assistance (VITA) publication #36E
- The Peace Corps classic. Chakroff wrote this manual from firsthand experiences while serving in the Philippines with the Peace Corps. While there is little information about tanks, the information about fish, their biology, and how to take care of them is accurate and accessible. Most libraries seem to have a copy - worth the effort and expense to photocopy this book if you can find it.
Mollison, Bill. 1997. Permaculture -A Designer's Manual Ten-speed Press.
Mollison, Bill. 1998. Introduction to Permaculture. Ten-speed Press.
- Bill is one of the most creative agricultural thinkers of this century. All of his works 'include sections on aquaculture and the underlying philosophy of permaculture is both interesting and useful for anyone who likes to contemplate our place in the world. Full of new ideas and practical advice.
McLarney, William. 1998. Fresh water aquaculture. Hartley & Marks, Port Roberts, WA.
- The standard textbook on small-scale, freshwater aquaculture, McClarney was a founding member of the New Alchemy Institute and worked with John Todd 'in his early career. This book was out of print for a long time but the 1984 edition has now been reprinted and it is available through special order. Lots of information and charts, but a lot of the contact information is out of date and useless. He tries to promote using North American species for aquaculture as opposed to introduced species like carp. I would not recommend purchasing this book unless you want to raise N. American species, want more technical information about aquaculture, or are interested in other forms (such as ponds, lakes, cages, etc.)
Logsdon, G. 1978. Getting food from water. Rodale Press, Emmaus, PA
An excellent but out of print book. Seems that all the alternative agriculture organizations were running interesting programs on aquaculture and aquaponics in the seventies. Now Rodale publishes magazines like "Men's Health" and the New Alchemy Institute is
defunct. This book is an excellent alternative to McClarney's text. It Is written in a more accessible style and seems to be more on the scale of home gardeners. There's even an account of an old man who raises catfish in a bathtub. Out of print but a valuable read if you can find it.
Todd, Nancy Jack and John Todd. 1994. From Eco-cities to Living machines: Principles of ecological design. North Atlantic Books.
John Todd and his wife outline their philosophies and ideas about ecological engineering and the role of ecology in design. Not a very handsome book, but it does have some interesting ideas about aquaculture, cities, and the future of the planet. Generally, while the ideas coming out if the New Alchemy Institute are pretty cool, the books and other publications from the members of this group are sort of vague and disappointing. If this group wants the world to change using its ideas, then they need to write a detailed manual about building living machines. There are a lot of willing people out there who are sort of puttering in the dark trying to do good things but apparently missing key details.
DeKorne, James B. 1992. The hydroponic hot house: low-cost, high-yield greenhouse gardening. Loompanics Unlimited.
DeKorne is the last of the paranoid survivalists, but has developed some very useful systems for growing things hydroponically indoors. He is an inventor who has limited resources - the results are accessible, cheap, and easy to build systems.
Resh, Howard Al. 1 990. Hydroponic home food gardens. Woodbridge Press.
Resh is the dean of commercial hydroponics in North America. Every
good hydroponics store will be stocked with his books, and libraries usually have a few copies. This book is the most accessible of his works, and although the ideas are fairly narrow-minded and conventional, at least it provides a solid survey of the hydroponic industry in general.
Douglas, James Sholto. 1985. Advanced guide to hydroponics (soilless culture).
Douglas, James Sholto. 1976. Hydroponics: the Bengal system.
- Douglas was one of the first writers about the 'new' science of hydroponics and he was very keen on organic and sustainable methods of production. If you can find any of his books, snap them up. Reading Douglas after reading Resh, you realize that Resh's entire scope would fit into a specialist chapter or two of Douglas' global perspective. Look for these books in the library.
Addey, William and Karen Loveland. 1998. Dynamic Aquaria. Academic Press.
A fantastic book about how aquariums and ecosystems work, written by two biologists. Full of explanations about how different environmental factors can influence fish and other organisms. Also has good ideas about how to stock an aquatic system with plants, fish, and other organisms.
Magazines
Of all the magazines published currently, the Growing Edge is by far the most relevant and useful. It often has article about aquaponics and
organic methods, and is an excellent source for latest hydroponic ideas. Practical Hydroponics and Greenhouses from Australia is equivalent to the Growing Edge in quality and outlook, but can be expensive because it is imported. The out of print Journal of the New Alchemist and the New Alchemy Quarterly have good articles about living machines but are rather difficult to find.
A good all-around gardening magazines is Organic Gardening. It is widely available and contains useful information about vegetables, composting, and the occasional water-gardening/hydroponic/aquaculture article. Older issues are better than recent issues, as the current editor seems more concerned about growing ornamentals than food.
Aquaculture Magazine the best source for industry news and format. Their articles are well written and researched, although keep in mind that the bottom-line is the driving force behind this magazine. Their annual Buyer's Guide is a must-have. It tells you where to get everything you could possibly need for aquaculture, especially sources of fingerlings.
All of these magazines have extremely useful back-issues. You can find these in a good library system or you can often buy them at a discount form the publisher.
Aquaculture Magazine
P.O. Box 2329
Asheville, NC, 28802
USA
www.aquaculturemag.com
The Growing Edge Magazine
1-800-888-6785
www.growingedge.com
Organic Gardening
Rodale Press
Emmaus, PA, 18049
USA
www.organicgardening.com
Practical Hydroponics and Greenhouses
P.O. Box 225
Narrabeen, NSW
2101 Australia
www.hydroponics.net.au
Journal of the New Alchemists, New Alchemy Quarterly - Both are out of print. Try contacting Ocean Arks International or your local public library to locate back issues.
Free Literature
Generally, your local extension agent will be able to provide you with information about some aspects of your proposed project. Here is one agency that has been particularly helpful.
Southern Regional Aquaculture Center
c/o Michael P. Masser
106A Swinger Hall
Auburn University, AL, 36849-5628
USA
(334) 844-9312
(334) 844-9208 (fax)
mmasser@acesg.auburn.edu
This center has put a lot of effort into promoting aquaculture. They have an excellent range of free publications, many of which are highly useful for recirculating aquaculture enthusiasts. They are one of the few places which promote crayfish, Chinese carps, tilapia, and exotic shrimps in the USDA system. They are also excellent sources of information about where to buy less common species. Ask for the following pamphlets in particular.
SRAC282 Tank culture of Tilapia
SRAC451 Recirculating aquaculture tank production systems. An overview of critical considerations.
SRAC 452 Recirculating aquaculture tank production systems. Management of recirculating systems.
SRAC 453 Recirculating aquaculture tank production Systems. Component Options
SRAC 454 Recirculating aquaculture tank production systems. Integrating fish and plant culture.
Herb, Frances Raising snails for food
WEB SITES
Web access is becoming more widely available, and even In the developing world Internet is available at reasonable prices
(approx. US$5 per hour) in Internet cafes. There are tons of resources on the Internet but beware anybody can write Just about anything in cyberspace and nobody checks their work. Be wise about advice and ideas that you glean off the Internet - if It sounds too good to be true, it probably is.
The following sites have useful information and will lead you to other sites.
www.jeffcook.com/hbpond.htm1
Jeff's half -whiskey-barrel page, while not quite as funny as Eric's is also full of information. He has a lot of different opinions from Eric, but the two end up with the same thing in the end. Jeff 's links are extensive.
www.livingmachines.com
The Living Technologies company site. This site is John Todd's consulting site. There are some interesting photos, information, and links, as well as examples of how Todd has applied living machines to industrial problems.
ext.msstate.edu/anr/aquaculture
Access to Mississippi State University's excellent collection of aquaculture extension information.
www.kloubec.com
- A major tilapia producer in Iowa, their site gives a good overview of this species.
ag.arizona.edu/azaqua/tilapia
- A large but disorganized site containing lots of information about tilapia.
www.itv.se/rainbow
- Swedish farmers who grow trout and vegetables in a recirculating system,
www.townsqr.com/snsaqua
- Home page of the Sperraneo family who are successful aquaponic farmers in Missouri.
www.cropking.com/store/AquaM/AquaSystem.htm
o A large-scale and high-tech aquaponic system made by a major hydroponic equipment manufacturer.
keywords to search with for internet information
aquaponics
hydroponics and aquaculture
living and machines
aquaculture and recirculating
alternative and aquaculture

ELECTRICITY USAGE

2009-01-23T10:44:00.001+08:00

How much electricity costs, and how they charge you.
Here's how you can check if you have plan to buy/install a pump-motor to your pond.

What the heck is a kilowatt hour?
Before we see how much electricity costs, we have to understand how it's measured. When you buy gas they charge you by the gallon.
When you buy electricity they charge you by the kilowatt-hour (kWh).
When you use 1000 watts for 1 hour, that's a kilowatt-hour.

When the number is low we sometimes use watt-hours (Wh) instead of kWh. For example, we might say 240 watt-hours instead of 0.24 kWh.

Watts and watt-hours
Watts is the measure of the rate of electrical use at any moment. For example, a laptop computer uses about 50 watts.
If your device lists amps instead of watts, then just multiply the amps times the voltage to get the watts.
For example:
2.5 amps x 240 volts = 600 watts

Understand the difference between watts and watt-hours
* Watts is the rate of use at this instant.
* Watt-hours is the total energy used over time.

To measure use over a period of time, we use watt-hours, not watts. The way it works is, watts or kilowatts for the amount at a given instant, and watt-hours or kilowatt-hours for the amount over a period of time.

How much does electricity cost?
The cost of electricity depends on where you live, how much you use, and possibly when you use it. There are also fixed charges that you pay every month no matter how much electricity you use. For example, I pay $6/mo. for the privilege of being a customer of the electric company, no matter how much energy I use.
Check your utility bill for the rates in your area. If it's not on your bill then look it up on the utility's website. The electric company measures how much electricity you use in kilowatt-hours, abbreviated kWh. Energy cost can be determined by knowing the amperage of an equipment, which is always listed, Volts x Amps = Watts.
The formula for kWh is Watts multiplied by hours used and then divided by 1000. For instance, a 800-watt water pump used for 10 hours would use 8.0 kWh. At 0.22 cent per kWh it cost $1.76

Maximum Demand
What is Maximum Demand?
Maximum Demand is calculated and billed by a kW demand meter, which records the highest kW value consumed in one 15 minute period, over a monthly billing cycle.
Demand Charges
Some utility companies also impose an additional charge based on the maximum amount of electricity you draw at any one time. This is called a demand charge. The following chart illustrates the concept. The shaded area is how much electricity you used, and you know you get charged for that. But the black bar on top is the demand, how much energy you "demanded" at any given point throughout the day. If your utility company has a demand charge (ask them), then you can save money by spreading out your electrical use throughout the day. Running appliances/equipments one after the other rather than at the same time would reduce your demand. And better yet, running them when you're not using much electricity for other purposes will reduce your demand even more.

Cheaper in the evenings
Some utilities have cheaper rates in the evenings. (Check with them to find out.) That's because it's harder for them to reach peak demand during the day when everyone's running a load. So they might charge less in the evenings to try to get you to move some of your consumption outside of those daytime hours. And even if your utility doesn't have cheaper rates at night, if your utility has a demand charge (see above), it could still pay to shift your extra demand to the evenings, because running two big motors at the same time results in a higher demand.

Gold Coin & Bullion Investing and Buying

2008-11-12T16:19:00.033+08:00

Gold Coin Images

Images and specifications of gold bullion coins, gold bars, and historic gold coins -- an overview of the most popular (and most interesting) investment items!

The Physical Gold IRA

Why gold makes sense in your retirement plan

As the ultimate long-term store of value, gold coins and bullion may very well be the ultimate retirement asset. Among the primary asset classes most often used in retirment planning -- stocks, bonds, annuities and savings accounts -- the tangible king of metals stands out as the only one that does not rely on the performance of another individual or institution for value. Former French president Charles DeGaulle once famously said of gold, it 'has no nationality and is eternally and universally accepted as the unalterable fiduciary value par excellence'. What better way to save for retirement than with the ultimate savings vehicle -- physical gold. We invite you to establish your gold retirement plan through USAGOLD.

Rollovers

Rolling over a Traditional or Roth IRA into a gold-backed IRA is relatively simple. The term "rollover" actually refers to the rolling over of assets in a 401(k) plan when the employee has separated from his/her employment. Separation from employment is the key to the ability to rollover the 401(k) assets into a gold-backed IRA. If no separation has occurred, then chances are very high that the plan holder will be barred from moving the assets out of the employer's 401(k) plan. However, there are exceptions to every rule, and a telephone consultation is always in order to see if the exception applies to you.

When it comes to existing IRAs, then the term "transfer" applies. Existing IRAs with banks, credit unions, stock brokerage firms or other financial service providers can be transferred directly to one of our referred trust companies. One very convenient option is to transfer either the cash in the account or the securities themselves. However, this arrangement is not always acceptable to the firm who is transferring your account. Again, for every rule there are exceptions -- which is why telelphone consultation is highly encouraged.

Approved precious metals investments

GOLD BARS & COINS: At present, gold bars with a purity of 24 karat (0.995+ fineness) are allowed into an IRA. They must be hallmarked by a NYMEX- or COMEX-approved refiner/assayer. These bars come in the following sizes: 1 ounce, 10 ounces, kilo (32.15 ounces), 100 ounces, and 400 ounces. Gold coins having a purity of 24 karat (0.9999 fineness) are the only ones allowed in an IRA, with the exception of the 22 karat US Gold Eagles. Readily acceptable for gold IRAs are the popular bullion coins from Amerika, Australia, Austria and Canada. The South African Krugerrand, being a 22 karat bullion coin, is not allowed.

SILVER: Regarding silver investments, only silver coins and bars with 0.999+ fineness are allowed. These include the 1 oz. US Silver Eagle, Canadian Silver Maple Leaf, and the Mexican Silver Libertad bullion coins. Investors can purchase 100 oz. silver bars and also 1000 oz. silver bars. Pre-1965 bags of US silver coins (dimes, quarters, half dollars, and silver dollars) are not allowed in an IRA because their alloy contains only 90% silver and thus does not meet the fineness standard.

PLATINUM GROUP METALS: Platinum and palladium bars and coins of 0.9995+ fineness can also be placed into a precious metals IRA. Both the US and Canadian Mints make 1 oz. platinum coins. Other countries, such as Great Britain and Australia, have 1 oz. platinum coins which are not as well known but also qualify. All platinum and palladium bars and coins must be from a NYMEX- or COMEX-approved refiner/assayer. Private companies with well-established hallmarks, such as Johnson Matthey and Englehard, manufacture platinum and palladium bars ranging in size from 1 oz. to 100 oz.

Gold Bullion Bars

Gold bar sizes: VARIABLE
Popular Gold Refineries: PAMP, Credit Suisse, Johnson Matthey, Metalor etc.
(1 oz. PAMP Fortuna gold bar shown above left)
Fineness: VARIABLE (.995 to .9999 is common)

Gold bars are produced in a wide variety of sizes, shape, and fineness, most of them destined for one-way transit to manufacturing end-users who intend to refabricate the gold into other forms such as industrial/electronic plating or decorative applications. Most gold bars are not intended for use as investment products (i.e., recirculated on the secondary public market) primarily because their authentic weight and purity both fall into question owing to the ease of tamperability once the bars have traveled outside of the original commercial chain of custody. However, one very notable exception to the use of gold bars for investment and financial purposes is with regard to the large (350-430 oz.) London Good Delivery bars that are maintained with a reliable chain of custody within the confines of an international network of central bank reserves and commercial bullion banking vaults. For the individual investor who demands more flexibility with regard to both portability and liquidity, gold coins fit the bill perfectly and are by far the most popular form of gold ownership.

Austrian Philharmonic Gold Bullion Coins

Vienna Austrian Philharmonics -- gold bullion coins
Fineness: .9999
Actual Gold Content: 1.0 troy ounce (31.103 grams)
Diameter: 37 mm
Face value: 2000 schillings or 100 euro (also minted in 1/2, 1/4, 1/10 ounce sizes)

Canadian Maple Leaf Gold Bullion Coins

Canadian Maple Leaf -- gold bullion coin
Fineness: .9999
Actual Gold Content: 1.0 troy ounce (31.103 grams)
Diameter: 30 mm
Face value: $50 (also minted in 1/2, 1/4, 1/10 ounce sizes)

U.S. Gold Buffalo Bullion Coins

American Buffalo gold bullion coins
Fineness: .9999
Actual Gold Content: 1.0 troy ounce (31.103 grams)
Face value: $50 (also minted in 1/2, 1/4, 1/10 ounce sizes)
(2006 mintage was one-ounce only)

The American Buffalo gold bullion coins are struck by the United States Mint's facility at West Point and have the distinction of being the first pure gold (.9999 fine, 24-karat gold) coins ever struck by the U.S. Mint for public sale as an investment product. Production of these coins was authorized by the Presidential $1 Coin Act (Public Law 109-145, dated December 22, 2005) and provides for gold bullion to be minted in the form of $50 legal tender coins, conveying that the content and purity is guaranteed by the United States Government.

According to the official U.S. Mint press release on June 20, 2006:

"This American Buffalo Gold Coin will appeal to both investors who choose to hold gold and to others who simply love gold," said Deputy Director David A. Lebryk during the ceremonial striking at the United States Mint at West Point, where the coins are being produced. "These classic and beautiful American Indian and buffalo designs by James Earle Fraser [a student of Augustus Saint-Gaudens], which have been American favorites since they were first used in 1913, recall a golden age of coin artistry."

[These bullion coins] portray the images of the revere

d Buffalo Nickel of 1913, Type 1. The iconic James Earle Fraser image of an American bison graces the reverse (tails side), and Fraser's classic design of an American Indian is featured on the obverse (heads side). The American Buffalo Gold Coin has inscriptions of the coin's weight, denomination and gold content incused on the reverse (Buffalo side) in the design area commonly known as the "grassy mound."

Australian Kangaroo Gold

Bullion Coins

Australian Nugget / Kangaroo -- gold bullion coins
Fineness: .9999
Actual Gold Content: 1.0 troy ounce (31.103 grams)
Diameter: 32.1 mm
Face value: $100 (Also minted in 1/2, 1/4, 1/10 ounce sizes)

South African Krugerrand Gold Bullion Coins

South African Krugerrands -- gold bullion coins
Fineness: .9167
Actual Gold Content: 1.0 troy ounce (31.103 grams)
Diameter: 34 mm (also minted in 1/2, 1/4, 1/10 ounce sizes)

Introduced in 1970, the South African Krugerrand, often misspelled as krugerand or kruggerand, was the first legal tender gold bullion coin to gain worldwide use in the modern era. To this day, many gold owners equate gold ownership with Krugerrand ownership. The Krugerrand received its first competition from the Canadian Maple Leaf, introduced in 1979. Eventually the Maple Leaf supplanted the Krugerrand as the world's top seller, gaining a significant market share as a one-ounce pure gold coin (.9999 fineness). In 1984 the U.S. Congress banned the import of the Krugerrand as part of the economic sanctions imposed on South Africa. The premium dropped to slightly-above the spot gold price and has never completely recovered.

Featured on the coin's obverse (and lending his name to the coin) is Paul Kruger, locally known fondly as "Uncle Paul" and elected four-time President of the Transvaal. The reverse features the springbok, a natural inhabitant of the dry savannahs, able to run at speeds up to 80 km/hr and jump over 10 meters. The springbok is the icon of the national rugby team.

U.S. Gold Eagle Bullion Coins

US Eagles -- gold bullion coins
Fineness: .916
Actual Gold Content: 1.0 troy ounce (31.103 grams)
Diameter: 32.7 mm
Face value: $50 (also minted in 1/2, 1/4, 1/10 ounce sizes)

Vietnamese Kim Thanh Gold Bullion Bars

Vietnamese Kim Thanh gold bullion
"bars" or leaves

Fineness: .9999
Actual Gold Content: 1.205 troy ounce (37.5 grams)
(Typically, three leaves wrapped in oil-paper: two leaves at 15gr apiece and a third at 7.5gr)

The incident is one of the most memorable of my career. Never before or since has the value of gold in preserving assets been made so abundantly clear to me. It was the mid-1970s. The United States was finally extricating itself from the conflict in South Vietnam. Thousands of South Vietnamese had fled their embattled homeland rather than face the vengeance of the rapidly advancing Communist forces.

In my Denver office, a couple from South Vietnam who had been part of that exodus sat across from me. They had come to sell their gold. In broken English, the man told me the story of how he and his wife had escaped the fall of Saigon and certain reprisal by North Vietnamese troops. They got out with nothing more than a few personal belongings and the small cache of gold he now spread before me on my desk. His eyes widened as he explained why they were lucky to have survived those last fearful days of the South Vietnamese Republic. They had scrambled onto a fishing boat and had sailed into the South China Sea, where they were rescued by the U.S. Navy. These were Vietnamese "boat people," survivors of that chapter in the tragedy of Indochina. Now they were about to redeem their life savings in gold so that they could start a new business in the United States.

Their gold wrapped in rice paper was a type called Kim Thanh. These are the commonly traded units in Hong Kong and throughout the Far East. Kim Thanh weigh about 1.2 troy ounces, or a tael, as it is called in the Orient. They look like thick gold leaf rectangles 3 to 4 inches long, 1-1/2 to 2 inches wide, and a few millimeters deep. Kim Thanh are embossed with Oriental characters describing weight and purity. As a gesture to the Occident, they are stamped in the center with the words OR PUR, "pure gold."

It wasn't much gold-about 30 ounces-but it might as well have been a ton. The couple consideredthemselves very fortunate to have escaped with this small hoard of gold. They thanked me profusely for buying it. As we talked about Vietnam and their future in the United States, I couldn't help but become caught up in their enthusiasm for the future. These resilient, hard-working, thrifty people now had a new lease on life. When they left my office that day, there was little doubt in my mind that they would be successful in their new life. It was rewarding to know that gold could do this for them. It was satisfying to know that I had helped them in this small way.

I kept those golden Kim Thanh for many years. They became something of a symbol for me-a reminder of the power and importance of gold. Today, when economic and financial problems have begun to signal deeper, more fundamental concerns for the United States, I still remember that Vietnamese couple and how important gold can be to a family's future. Had the couple escaped with South Vietnamese paper money instead of gold, I could have done nothing for them. There was no exchange rate for the South Vietnamese currency because there was no longer a South Vietnam! Wisely, they had converted their savings to gold long before the helicopters lifted U.S. diplomats off the roof of the American Embassy in 1975.

Over the years, I have come to understand and appreciate the many important uses of gold.

U.S. Gold Double Eagles

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Double eagles were so named because the largest U.S. coin until the time of the California gold rush was a $10 face value (approximately ½ troy ounce) gold Eagle. When Congress in 1849 authorized the large $20 gold piece to efficiently coin the bonanza of gold coming from the California gold fields, it naturally came to be called the ‘double’ eagle.

Later gold discoveries in Nevada, Arizona, Colorado, and Alaska caused hundreds of millions of ounces of gold to be coined at the U.S. Mints into these large double eagles. Gold double eagles are the wealth born of the Old West gold mining days. For the world, the U.S. $20 gold double eagle symbolized the vast riches of the United States in the second half of the 1800s.

These coins have always represented a lot of money. In 1900, a double eagle $20 gold coin was more than the average week’s wages for most people.

To demonstrate the purchasing power of a double eagle, imagine a weekend in New York City in 1900. A night’s stay at the Plaza Hotel cost $1.50, a lunch of a beer and a sandwich was a nickel, theatre tickets on Broadway might cost you 35c, and a five-course dinner at the finest restaurant in the city, Delmonico's, would set you back all of 75 cents. In other words, you would have a hard time spending the whole twenty dollars while splurging on a first-class weekend in New York!

We bring you affordable, lightly circulated gold money from the era when a dollar was a dollar. And because these are not flawless, museum-quality specimens, you can carefully handle and enjoy these gold treasures. Feel free to hold them in your hand – that’s the feel of real gold, a treasure you can hold and possess as have only a fortunate for thousands of years…

If you had a stack of these one hundred years ago, you had quite a treasure! And the same is true today. Although our population has increased, and our national wealth is higher, there still exists only a limited supply of these old $20 gold pieces – just as there is a limited supply of gold!

When you purchase these gold double eagles, your acquisition will resemble a treasure that was put away generations ago. The historic Liberty Head design (designed by James B Longacre, who also designed the Flying Eagle and Indian Cents) was last struck in 1907, so all the coins we offer here are products of the San Francisco and Philadelphia mints from 1877 to 1907. Not only do you have a substantial gold value (each double eagle by law contained .9675 ounces of pure gold), but you also have a direct connection to the romance of the western gold discoveries, from the ‘49ers in old California to Alaska in 1898. The gold double eagle is a piece of America’s historic wealth that you can hold in your hand.

These U.S. double eagles make very welcome gifts. They have a monetary value, a value in gold, and they hold the power of timelessness. These gold coins come to us from generations ago, and will become part of your family heritage for generations in the future. There is an undeniable magic in the act of handing these old coins over to your children, grandchildren, and heirs. As material gifts go, there is no better gift than the gift of gold. And giving these historic double eagles makes the presentation even more memorable – exciting for the recipient, and flattering to the giver.

There are power, intrigue, and mystery surrounding these old coins:

Where did this fortune in gold come from? How did these large gold coins survive all these years? Where were these gold double eagles hidden when gold was called in, back in 1933? What is the future of this treasure for my family and heirs?

Today, in the 21st Century, you still have the opportunity, at a reasonable price, to convert part of your own wealth into a permanent and portable gold legacy of 19th century gold coins.