WATER SOURCES OF FISH PRODUCTION
Base on the water sources of fish production, three types of fisheries can be recognized:
- Marine Fisheries
- Fresh Water Fisheries
- Inland water Fisheries
Aquaculture pertains to production of useful (ie, of high economic value) aquatic plants and animals such as fishes, prawns, crayfish, lobsters, crabs, shrimps, mussels, oysters and seaweeds by proper utilization of available waters in the country.
COMPOSITE FISH CULTURE (POLYCULTURE OF FISH)
- The yield obtained by inland fishery is not that high. And so, it is sometimes combined with rice crop farming. This process of fish farming alongside agriculture is known as composite fish culture system.
- The food habits of these six species are as follows
- Fish production by culturing a single species in a pond (called monoculture). The silver carp (Hypophthalmichthys molitrix) is a surface feeder which feeds on phytoplankton.
- The catla (Catla catla) is also surface feeder which feeds on zooplankton.
- The rohu (Labeo rohita) feeds in middle zone of the pond, i.e. column feeder which feeds on decaying plants and detritus.
- The grass carp (Ctenopharyngodon idella) feeds on all macro-vegetation and consumes the aquatic plants/ weeds not used by other species in this group.
- The mrigal (Cirrhinus mrigala) is a bottom feeder using decaying plants and detritus.
- The common carp (Cyprinus carpio) is an omnivorous bottom feeder.
These six species possess complementary feeding habits and do not harm each other, and constitute a good combination of polyculture.
FACTORS TO BE TAKEN INTO CONSIDERATION FOR FISH CULTURE
Important factors to be taken into consideration for fish culture include:
- Topography or location of pond;
- Water resources and quality;
- Soil quality.