Fish farming

a general view to procedures in fish farm

1. Fish farming or pisciculture involves raising fish commercially in tanks or enclosures such as fish ponds mostly for food . Fish farming

2. Miriculture It is the cultivation of marine organisms including fish, sea weed or shell fish Fish hatchery This involves breeding juvenile fish to release them in wild or sell them .

3. Categories Fish farming can be categories into three main classes Extensive the fish feed entirely from the food web within the pond which maybe enhanced by the edition of fertilizer and manure Semi-intensive the fish still obtain significant nutrition from the food web within their pond . But they’re also given supplementary feed Intensive the fish are kept in a high stocking density . Fish are totally dependent on supplementary food. This also need high inputs and management of water quality .

4. Types of fish farming Fish pond culture (single specie , composite fish culture ) this is the traditional method of extensive fish farming Cage system farming fish cages are placed in lakes , rivers, an ocean , or also called offshore cultivation

5. Major species Grass carp Silver carp Common carp Trout Milk fish Rohu Northern snakehead Amur catfish Nile tilapia

6. Starting a fish farm Site selection Selection of fish species Construction of structures Building an optimum ecosystem Introduction of fishes Feeding Maintenance and care Harvest Marketing Breeding Diseases Cautions

7. Site selection When thinking of setting up a fish farm, the first step is selecting the site which depends on topography , potential flooding or drought ,climatic condition,transport , water availability ,security etc.

8. Selection of species Selection of species is dependent on regions ,the climate , hardiness of the species , prolificacy of specie ,

9. Construction of structures The main structures in fish farms are fish tanks/ ponds holding tanks these tanks are used as quarentines , to acclimate new fishes Breeding tanks these tanks are used for the process of breeding and are also as brooders Rearing tanks these are the largest in size and the fish spend most of their farm life in these tanks .( grow-in)

10. Water inlet/ source Water source could be some nearest canal , river , lake or a tube well Aerators these supply oxygen and provide water flow Filtration system removes debris and waste .

11. Building the ecosystem The ponds are filled and run for two to three weeks without adding the fish to start the nitrogen cycle which ensures optimum pH , level of nitrates and nitrites needed for healthy fish stock .

12. Introduction of fishes The fishes are first kept in quarantines tanks to acclimate them with residual water conditions gradually , to avoid sudden shocks .

13. Feeding In extensive farming growth of natural food is in ponds is stimulated by the use of fertilizers while in intensive farming commercial ffod usually in the form of pellets is given .it might be made up of vegetables or fish oil and proteins .

14. Maintenance and care Special care is needed during the first few weeks after hatching . General measurements include changing water level with temperature providing food and fertilizers regularly filtering and aerating the water .observation for disease symptoms should be made to avoid infestation

15. Harvest Harvesting involves lowering the water level so the fish are easier to catch .a fine net is used to take fish out of water into portable tanks

16. Breeding When the breeding season arrives , the breeder specimens are taken out into the breeding tanks . Where they might be injected with breeding hormones depending on the species. methods of breeding breeding can be classified into two main methods . Natural breeding Manual breeding

17. Natural breeding I n this type the fishes perform their mating rituals and breed by themselves , though this behavior might be introduced through injections

18. Manual breeding Mature fishes are selected and the females are fist taken out of water covered in damp towels . Pressure is applied on their abdomen against their vent to release eggs , which are collected in a container . Male fishes are milted in the same way , milt is mixed with the eggs so they can be fertilized . These eggs can then be placed into hatcheries .

19. Diseases: Dropsy symptoms; Bloating of the body, protruding scales treatment ; add antibiotics in food

20. Fin rot symptoms ;blood on edges of fins , expose of fin rays , disintigrated fins treatment ; Treat the water or fish with antibiotics

21. Ich symptoms; problem in breathing , clamped fins, loss in appetite . treatment ; quinine hydrochloride at 30 mg per litre

22. Visit to fish hatchery R awal town I slamabad We paid a visit to the fish hatchery rawaal town .

23. THE HATCHERY: The hatchery had two main buildings , the jar hatchery and the rearing ponds. It also had an admin block with office for customer services.

24. The jar hatchery: Even though the building was named jar hatchery , the jar hacthery inside wasn’t functioning from years as its capacity couldn’t fulfill the requirements. Circular breeding tanks were used instead as conditioning or brooding tanks. It also had holding tanks for breeder fishes. One circular pond had some trout babies in it.

25. THE REARING PAANDSSSSS: There was a total of 7 rearing ponds , each one spread across app. 1.5 acres . Only one pond was functional and housed 200 breeder individuals of rohu and grass carp species. This pond was filled with trunks and branches of eucalyptus as a protection of fishes against aerial predators.

26. BREEDING PROCESS: Breeding process starts with the withdrawal of fishes from the adjoining rawal dam in the months of feb and march. The breeding starts in the months of April , May . During these months breeder fishes are taken out of the rearing ponds and placed in the holding ponds inside the hatchery. These fishes stay in these for atleast 7 hours and are then transffered to the circular ponds .

27. Cont.: Then they are injected with ovaprim , this nourishes the eggs and boosts breeding behaviour . After 5 – 7 hours of injection the fishes are ready to spawn. Rohu and Mori species breed naturally in the circular tanks and then they are removed as the finish egg laying and fertilization.

28. Cont.: Other species don’t breed naturally so they are spawned manually. Injected fishes are taken out of the circular tanks when they are ready and hand spawned. The fishes are first cleaned with a clothe and then covered in a damp towel . Pressure is applied on the fishes across abdomen to the vent. Females release eggs and males release milt.

29. cont.: The eggs are released into plastic tubs followed by milt. Eggs and milt are mixed with a chiken feather to avoid any damage to their fragile structures. The eggs sit in the tub until they swell to a proper size , which is a sign of fertilization. Then they are transfered to the circular tanks which are made ready prior to the additions .

30. FRY CARE: The eggs develop into fries in around 24 hours of fertilization . These fries depend on their yolk sac ( food source attached to lower abdomen) for food for the first 3 days of their life. After these 3 days they are transferred into the rearing ponds where they grow the rest of their hatchery lives which ranges from 3 to 5 months. Their first supplementary food is rice porridge and daphnia ( tiny organisms cultured in the pond itself by the addition of manure).

31. Cont.: No special care practices are usually made. Water quality is taken into consideration , its flow and aeration is maintained Regular feeding is done , and inspections are made for any mortalities , diseases etc.

32. HARVEST: The babies are harvested using nets , workers go inside the ponds and use nets to take out babies . First withdrawal is made at 3 months . At this point the fries mostly are the size of an inch Some babies are grown on to around 5 months of age and they grow up to a size of 3 inches.

33. MARKETING: This hatchery only sells fries . The fries are sold in a minimum stock of a 1000 individuals. 3 month old fries are sold for Rs . 2500 for 1000 fries. The 5 month old fries are sold for Rs . 5000 per 1000 fries.

34. Thank you