Prior to a farmer starting fish farming, there are a few fundamental contemplations to guarantee achievement. These include:
Design of the Pond
When choosing the pond site and configuration, there are a few variables to be considered. A portion of these are:
Source of water to fill the pond and how the same water will be brought to the pond:
The general rule is that the pond water inflow and outflow should measure up to the pond volume over the time of a month. On the off chance that the inflow is too low, water quality may experience the ill effects of oxygen exhaustion as well as collection of toxicants. In the event that the water surge is too high, a lot of valuable green growth might be flushed out from the pond. The water should keep the pond full all through the culture period. The pond should top off in under seven days. Place screens on pond deltas and outlets to keep out predators, creepy crawlies and undesirable fish and furthermore to hold the cultured fish.
Size, shape and pond depth:
Moderately shallow ponds are profitable. In any case, the shallow end ought to be no less than 0.5m deep to keep away from invasion by weeds and predation of the fish. The size and state of the pond can shift contingent upon the fish species, fish populace and the farmer’s preferences. It’s important that on the off chance that you need to produce fingerlings, you will require all the more small ponds while a food fish producer requires moderately large ponds.
Slope of the pond base:
The bottom of the pond must have an adequate slant for good drainage. A slant with a drop of 2cm for each 10m along the pond bottom is appropriate. On the off chance that the slant is excessively gentle, the pond won’t be easily drained. In the event that the pond is excessively steep, it might be excessively shallow toward one side or too deep at the other end. Pond ought to be drainable.
Height, width and Slope of the dyke:
The perimeter and feeder streets are required for machines movement during construction and harvest. If you intend to drive on the dykes, assemble them no less than 3m wide to top and at the base.
Top soil is high in organic material and ought not be used to construct pond dykes. Land ought to be made out of good quality soil, with practically no rock or shakes on the surface or mixed in. Areas with rocky, gravelly, or sandy soil are not suitable for pond construction. Soil that will be used to build the dykes must contain no less than 20 percent clay so the finished pond will hold water throughout the growing period.
Fish Species suitable in Kenya
There are three major fish species which can do well in the Kenyan climatic conditions. They are Nile tilapia (Oreochromis niloticus), African catfish (Clarias gariepinus) and Trout
This is a warm water fish and is mainly cultured in fresh water environment. It thrives well in water temperature of between 20-35 degree Celsius. It attains sexual maturity at two months. Tilapia feeds lower in the food chain i.e. feeds mainly on phytoplankton, zooplankton and detritus.
Stocking rates range from two to six fingerlings/m2, depending on the level of management. Male tilapia are known to grow almost twice as fast as females.
It is therefore preferable to stock only males (monosex culture) to achieve the fastest growth and reach market size in the shortest possible period, resulting in more proteins and profits. A major management problem of pond-cultured tilapia is excessive reproduction and the subsequent stunting of fish due to overcrowding.
Methods of controlling overpopulation include manual sexing of fish, use of sex-reversal hormones to produce all males, and use of predators.
The success of these methods may rest with how well a fish farmer understands the techniques.
It grows in the same agro climatic regions as tilapia. The water temperatures of between 26-33 degrees Celsius are ideal. It attains maturity at two years of age or at 200-500 grams. It feeds mainly on zooplanktons. Their stocking rate is 100-450 fry/ m2.
Catfish has a drawback of high mortality of fry especially during the first 14 days after eggs hatch
It’s a cold water fish and it’s best grown in high altitude regions where water is cooler. Its presently limited by availability of seeds and quality feeds in the country
Pond preparation for stocking
The procedure below should be followed by the farmer to the latter when preparing the pond for stocking. These steps will help boost the productivity of the pond.
- For an old pond, drain all water and allow it to dry for 14 days.
- Apply lime to the pond bottom and dyke slopes. Choose agricultural limestone (CaCO3) for application in your fishpond
- Apply organic fertiliser in the pond before filling it with water. The most common examples of organic fertilisers are animal manures (from cattle, poultry, donkeys, rabbits, sheep and goats) and decaying plant matter, such as cut grasses.
- Fill the pond with water.
- Apply inorganic fertiliser in the pond after it has been filled. Apply DAP and UREA to your fishpond at the following rates: wwDAP: 2 g/m2/week (or weekly applications of 15 tablespoons DAP for every 100 m2) wwUREA: 3 g/m2/week (or weekly applications of 30 tablespoons urea for every 100 m2).
There are various feeds that can be offered to the fish in the pond. Some commonly available feeds include:
— Dry sinking pellets
— Moist sinking pellets
— Floating pellets
The feeds can be formulated so as to meet the body requirements of the fish species. This can be done as follows:
- Cotton seed cake— 37%
- Wheat bran— 57%
iii. Fresh shrimp— 6%
- Vitamin premix
Feed ingredients can be hand ground or a manual grinder can be used. It’s important to adhere to the four fixes (4Fs) when feeding fish. These are:
- Fixed feed quality.
- Fixed feed quantity.
- Fixed feeding location.
- Fixed feeding time.
The fish should be fed between 10am and 4pm when the water temperatures and dissolved oxygen content are reasonably high and the fish are active.
Fish farming is a very profitable enterprise if done with good management. Farmers should develop passion towards this less exploited agricultural opportunity. Join me next week as we go through handling, seed production, marketing, hatchery management and fish farming economics among other topics on aquaculture.
The fish ought to be fed between 10am and 4pm once the water temperatures and dissolved oxygen content are moderately high and therefore the fish are active.
Fish farming could be a very profitable business if sensible management is done. Farmers ought to develop passion towards this less exploited agricultural opportunity.
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