Pond stocking

Stocking

Before stocking, you have to think of selling. Find out at the market/restaurants which species and what size of fish people prefer and then calculate your stocking. Grow the right species up to a size that is both profitable and easy to sell.

Know your market and calculate! 5 fish of 200 grams each = 1 kg. Each piece is sold at 120 shillings which is in total 600 Ksh /kg
2 fish of 500 grams each = 1 Kg. Each piece is sold at 200 shillings which is in total 400 Ksh /Kg.
Actually you make more profit with the smaller fish, but if people in your area only like the big fish you will not be able to sell them!

Once you know what size of fish to grow you can calculate how many fingerlings you will have to buy. Stocking too many fish will lead to slow growth because they’re competing for feed and space; this is called stunted growth.

Low stocking density means that you are losing out on profit. new to fish farming start with the lower stocking density because management is easier and there is less risk of the fish getting diseases or lack of oxygen.

You will use your space and time more efficiently if you first stock your fingerlings in a hapa in an existing pond with green water. Once the fingerlings reach 5 grams you can stock them in their pond until harvest.

A pond full of tadpoles is especially disastrous if you are going to stock very young fry, but from 5 grams upward they will not be eaten by frogs.

Mortality

In fish farming you have to take into account that some fish will die either through diseases, damages or predators. Therefore you will have to buy more fingerlings than the desired number of fish at harvest; a rule of thumb is that mortality is 10% over a period of 6 months. Meaning if you buy 1000 fish, you will end up with 10% less which is 900. When starting with fry or small fingerlings overall mortality can be over 20%.

Stocking the pond

Stock the pond with all male tilapia fingerlings. The use of mixed sex tilapia is not recommended because:

1.Males grow 30% faster than females and

2.Mixed sex tilapia will start to reproduce after a few months.

 All male tilapia fingerlings grow much faster than mixed sex tilapia fingerlings.
This means you spend more on stocking, but in the end you will make more profit.

The recommended minimal size for stocking tilapia fingerlings into an open pond is 5-10 g. If you can only get smaller tilapia it is recommended to stock them in hapas first until they have grown to 5-10 g or even bigger.

In the hapas they are safe from predators like frogs and a cover net will keep them safe from birds. You can stock 500 fish in a 5 m² hapa net. Start feeding the fish one or two days after stocking to allow them to recover from stress of transport.

Fine mesh hapas will become clogged with algae growth if not cleaned frequently. Clogging prevents fresh water from circulating into the hapa and can result in a low oxygen condition which kills fish.

Larger mesh sizes (rashel) allow greater water exchange in the hapa, and are used for nursing fingerlings stocked at high densities. A cover is often attached over the hapa to prevent brood fish from jumping out and keeps predatory birds out.

Advantages of the hapa system

1.Separation of brood fish and fry is easy.

2.Maximum recovery of fry is possible because brood stock are enclosed in nets.

3.Hapas may be set up in many different areas where it might normally be impossible to stock brood fish or nurse fry.

Disadvantages of the hapa system

1.Organisms in the water and uneaten food may clog the mesh. This limits water circulation in the hapa and may cause low oxygen problems. The net may need periodic scrubbing to remove fouling organisms from the mesh.

2.The fry can only eat the algae inside the hapa and cannot use the whole pond space.

3.Netting material may degrade in sunlight and need replacing annually. To avoid this do notdry nylon nets in direct sunlight. Properly cared for nets may last 5 years.

4.Fish may easily escape if the netting is torn.

5.Fish may be easily stolen from hapas.

6.Females incubating eggs may spit them out when hapas are inspected for fry.

Fish breeding and hapas

You can produce your own fingerlings, but before you do that, ask yourself the following questions and calculate!

Key question and calculation to make is: what are all costs involved to produce my own quality fingerlings and at what cost can I buy fingerlings?