Photo: anonymous · Public domain · source ↗
Composite fish culture (six-species)
Composite fish culture, also called carp polyculture, is the simultaneous stocking of complementary carp species in a single freshwater pond so that all feeding niches in the water column are utilised. The six-species model — three Indian Major Carps (IMC) plus three exotic carps — was standardised by ICAR-CIFA Bhubaneswar and the All-India Coordinated Research Project on Composite Culture from the 1970s, and is one of the most productive freshwater aquaculture systems in the world.
Principle
The six species partition the pond by feeding niche:
| Species | Niche | Recommended share |
|---|---|---|
| Catla (Catla catla) | surface zooplankton | 15-20% |
| Silver carp (Hypophthalmichthys molitrix) | surface phytoplankton | 10-15% |
| Rohu (Labeo rohita) | column omnivore | 15-20% |
| Grass carp (Ctenopharyngodon idella) | macrophyte feeder | 10-15% |
| Mrigal (Cirrhinus mrigala) | bottom detritus | 15-20% |
| Common carp (Cyprinus carpio) | bottom omnivore | 15-20% |
Because the six species do not compete for the same food, total fish yield per hectare exceeds what any single species or three-species system would produce on the same pond.
Implementation
ICAR-CIFA recommends a six-species ratio of roughly 4:2:3:1 across surface, column, bottom and macrophyte feeders, with silver and common carp completing the mix. Stocking density is 5,000-10,000 fingerlings/ha. Pond preparation follows standard earthen-pond engineering (Fish Pond Construction): drying, liming at 250-500 kg/ha, organic manuring with cow dung at 5,000-10,000 kg/ha and inorganic fertilisation (urea, single super phosphate). Supplementary feeding of rice bran and oil-cake (1:1) is given at 2-3% body weight. Grass carp are fed directly with fresh grass, paddy straw and aquatic weeds. Compared with the simpler three-species system (Carp Polyculture Pond), the six-species model adds phytoplankton (silver carp), macrophyte (grass carp) and bottom omnivore (common carp) niches, raising yield by 20-30%.
Adoption context
Reported yields under recommended management are 4-7 t/ha/year of table-size 1-1.5 kg fish, against 3-5 t/ha for three-species ponds. The six-species package is promoted under PMMSY through subsidies for pond construction, seed and feed. Andhra Pradesh, West Bengal, Punjab, Haryana and Uttar Pradesh are the major adopters.
Limitations
Yields decline sharply with poor seed quality, inadequate liming or fertilisation, and predation by birds and snakes. Stunted growth and disease outbreaks are common where stocking ratios are mismatched to plankton load. Silver and common carp are exotic species; release into open waters is discouraged in sensitive ecosystems.
Related pages
See also: Carp Polyculture Pond, Catla Catla Indian Major Carp, Rohu Labeo Rohita Imc, Mrigal Cirrhinus Mrigala Imc, Silver Carp Hypophthalmichthys Molitrix, Grass Carp, Common Carp Cyprinus Carpio, Bighead Carp Aristichthys Nobilis, Fish Pond Construction.
Sources
- Composite fish culture. Vikaspedia.
- Freshwater Aquaculture: Composite Culture. ICAR-CIFA Bhubaneswar.
- Carp polyculture in India. Global Seafood Alliance.