ABSTRACT
Aquaculture means ‘water farming’, just as agriculture means ‘field farming’, and so it encompasses fish culture and growing aquatic vegetables. The fish most frequently grown in aquaculture ponds are carp and tilapia. Local species should be grown – in India, for example, Indian major carp are mainly grown, such as catla (Catla catla), mrigal (Cirrhina mrigala) and rohu (Labeo rohita). Kolkata (formerly Calcutta) provides the world’s largest example of wastewater-fed fisheries (Jana, 1998*; Nandeesha, 2002*): around 3500 ha of fishponds are fertilized with 550,000 m3/day of untreated wastewater (Figure 22.1), and fish production (Indian major carp, with some tilapia and silver carp) is ~20 tonnes/day, equivalent to ~18 per cent of the city’s demand for fish. The average fish yield is 4 t/ha year, although the better managed ponds produce 7-8 t/ha year. Some 17,000 local people work on the fishponds (Edwards, 2001*), and the fish sell for around US$1/kg – it is a highly profitable business.
