Major carps have proved to be best culturable fish in India as:
i) Carps feed on zoo and phytoplankton’s, decaying weeds debris and other aquatic plants.
ii) Carps can survive under somewhat higher temperatures and also in turbid water.
i) Carps can tolerate oxygen variation in water.
ii) Carps have fast growth rate and can attain good size and weight.
iii) Carps can be transported from one place to another easily.
iv) The flesh of carps is mostly palatable and much nutritive.
The culture of carps has to be tackled from the point of view of breeding hatching, nursing-rearing and stocking ponds.
It is the first step of culture of carps and thus proper ponds are prepared called breeding ponds. There are two categories of breeding.
i) Natural Breeding: Natural bundhas with natural riverine conditions are managed for the breeding of culturable fishes. These bundhas are three types:
1. We bundh: These are perennial bundhs.
2. Dry buindh: These are seasonal bundha.
3. Modern bundh: These are pu8cca bundhs.
(ii) induced Breeding : In this method ova from females and sperms from the males are taken out artificially and the eggs are got fertilized by two methods.
Fertilized eggs are kept into hatching pit for hatching. At the time of the construction of hatching pits one should see that the hatching pit.
1. Should be near to the breeding grounds.
2. Should be smaller in size.
3. Should contain such a quantity of water which must dry within a month or two.
4. Should be more in number.
Then the fish fries are collected and transported to nurseries. Before this dead fries should be removed to avoid pollution and infection. Now a days fries are transported in sealed metal containers with oxygen.
In India alkethen bags of different sizes are used for the transportation of fish fries from hatching hapas to nursery-ponds. In nursery ponds natural resources of food are less and when large numbers of fries are released they certainly suffer due to lack of food.
First of all predatory and weed fishes would be removed from pond. The chemical fertilizers like ammonium sulphate, sodium nitrate and superphosphate should be used along with cow-dung. Due to this numerous zooplanktons and phytoplanktons develop and used as food.
(d) Rearing ponds:
For good health and growth of fingerlings the exercise is essential for them inside the rearing ponds. So these fingerlings are reared in larger and narrower ponds to provide them long distance for swimming. Then fingerlings are transported to stocking ponds in a container of 1000 litre capacity.
(e) Stocking ponds:
The stocking ponds should be cleaned of weeds and predatory fishes. Sufficient food is essential for good growth of fishes in these ponds, hence proper manuring should be done for the production of zooplankton because large number of fishes may not be able to feed properly due to lack of food material. The amount of fertilizers used is totally kept in the stocking ponds. When fishes attain maximum length and weight they should be harvested.