44 December 2011 Modern approach of composite fish culture — the examples of Andhra Pradesh (India) to emulate Sagar C. Mandal1*, Debtanu Barman2 and Pronob Das3 The technology developed for fish culture in two or more species of compatible fishes are cultured simultaneously is the most advanced and popular form of aquaculture in India and is known as composite fish culture. This technology enables farmers to get maximum fish production from a pond through utilization of available fish food organisms in all the natural niches supplemented by artificial feeding. Any perennial freshwater pond retaining water depth of 2 m can be used for fish culture. However, the minimum level of pond depth should not fall below one meter. Composite fish culture, which was developed at CIFRI, Cuttack Centre in the 1960s, has come a long way through the efforts of various research and extension projects of the ICAR, Central/ State Governments and the agricultural universities. Fish Species in Composite Fish Culture Depending on their compatibility and food habits, a variety of Indian fishes as well as exotic varieties have been recommended for culture using composite fish culture technology. Table 1 shows the different types and food habits of fishes that are extensively used for composite fish culture in different parts of India by farmers as well as research institutes. Pond Management Pre-Stocking. For a new pond, pre-stocking operations start with liming and filling the pond with water. The first step for an existing pond requiring development deals with clearing the pond of unwanted weeds and fishes either by manual, mechanical or chemical means. Removal of unwanted and predatory fishes and other animals is done by repeated netting or using mahua oil cake at 2,500 kg/ha or by sun drying the pond bed. Acidic ponds are less productive and, therefore, lime is used to bring the pH to the desired level. Lime also has following effects: a. Lime increases the pH and acts as buffer and avoids fluctuations of pH. b. It increases the resistance of soil to parasites. c. Its toxic effect kills parasites and d. It hastens organic decomposition. Normally, lime is used at the rate of 200 to 250 kg/ha. View of composite culture ponds in AP. Table 1. Important cultivated fish species with their different feed habits. Indian Major Carp Catla Zooplankton feeder Surface feeder Rohu Omnivorous Column feeder Mrigal Detritivorous Bottom feeder Exotic carp Silver carp Phytoplankton Surface feeder feeder Grass carp Herbivorous Surface, column and marginal areas Common carp Detritivorous/ Bottom feeder Omnivorous Table 2. Recommended doses of lime based on soil pH. Soil pH Lime (kg/ha) 4.5-5.0 2,000 5.1-6.5 1,000 6.6-7.5 500 7.6-8.5 200 8.6-9.5 Nil
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