Fish Farming – Pond Management and Economic Importance | Biology Class 12

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Fish FarmingReference Notes
Fish Farming – Biology
Science Grade XII

It is the commercial rearing of fish for human consumption. The term fish farming generally refers to pond fish culture where fishes are grown in the ponds for commercial purpose. During selection of fish for its farming following points should be considered.

  1. They should be able to use natural and artificial food.
  2. They should have fast growth rate with high fertility.
  3. They should have high market value.
  4. They should be able to resist diseases.

Common cultivated fishes in Nepal are Rohu, Nainy, Catla, Bhakus, Common Craps, Grass Carps, Silver Carps and Sahar.

Pond Type:

For fish farming, ponds of various types are needed which should near to market. Pond should be constructed where permanent source of water is available. Pond should be gently sloped towards outlet so as to make easy for complete drain off water while cleaning the pond. Different types of ponds are required for sustainable fish farming which are as follows:

  1. Segregation Pond
    This pond is for separation fully mature male and female before breeding season. The matured males and females are called brooders which must be two to three years old and weight about 5 kg.
  2. Breeding Pond
    It is a small pond covering an area of 0.3 hectare and having continuous supply of slow moving water. In breeding pond male and female brooder are kept in the ration of 2:1 in rainy season for spawning.
  3. Hatchery Pond (Hatching Pond)
    The fertilized eggs of collected form breeding pond and transferred for small pond called Hatchery Pond. It is made rectangular. With the help of mosquito net, and such rectangular are called as Hapas. The fertilized eggs are hatched within 2-3 days and newly hatched hatchlings are called as fries or fingerling which is kept in hatchery pond for 2-3 weeks.
  4. Nursery Pond
    It is rectangular pond in which fries are kept for 1-3 months till they become 10-40 gm weight. Wheat flour mixed with soybeans flour is used to feed the Fries.
  5. Rearing Pond
    It is a big pond covering an area of 20 hectare with an average depth of 2 meter. The fries are left for growth and if fed well the fish may attain body weight of 2 kg in 5-10 month. These fishes are called as table fish and are ready for marketing.

Condition necessary for fish farming (Pond Management):

The physicochemical parameter of pond should be managed properly for betterment of production. Following permanents should be considered for pond management.

  1.  Soil
    The pond must be constructed in the place where soil is of day loam types. In sandy places the pond is not constructed because it causes water leakage.
  2. Water
    The pond must be regularly fed with water and the green water is considered to be best as it contains more dissolved oxygen.
  3. PH. of pond water
    The PH. Of water should be optimum about 7-8. in case of acidic water lime is added to maintain optimum PH.
  4. Light
    The pond should be constructed at open space so that pond water receives sufficient light for photosynthesis. The photosynthesis provides required food materials and oxygen for respiration.
  5. Turbidity
    The pond water should be slightly turbid and in high turbidity, the gills are blocked and cause mass death.
  6. Manuring
    The growth and production of fishes depends upon the amount of food present to them. Therefore, for the growth of vegetation NPK fertilizer and manures should be introduced into the pond.

Economic Importance of Fish Farming:

  1. It offers an opportunity of self-employment and income.
  2. It is a source of meat that provides protein and helps in reducing malnutrition.
  3. Fish leather can be used for manufacturing purse, shoes, belt, bags, etc.
  4. Fish oil can be extracted from fish liver which is very nutritious.

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