World Aquaculture - September 2023

WWW.WAS.ORG • WORLD AQUACULTURE • SEPTEMBER 2023 55 (CONTINUED ON PAGE 56) Classification of Freshwater Cage Farming and Selection of Species Cage culture can be done in extensive, semi-intensive and intensive modes in selected water bodies. The method of cage culture that can be applied is mostly decided by the natural productivity of water. In open water with low productivity more inputs and management are needed. In contrast, water bodies with high productivity require lower feed inputs and management. In extensive cage culture, feed is not required. Phytoplankton and zooplankton are utilized as natural food sources. Cage culture as a semi-intensive practice requires a low protein (< 30%) supplementary diet. If the required feeds exceed 30% protein content, the practice can be considered intensive. Considering the consistent demand for fish in the Indian Recently, the Indian government has proposed to increase fish production through technological promotion of cage culture. Initiatives funded by state governments include the National Mission for Protein Supplements in Tamil Nadu and Jharkhand. Currently there are about 6000 cages of varying dimensions installed in different wetlands of India. States like Jharkhand, Chhattisgarh, Odisha, Telangana, Maharashtra and Madhya Pradesh have made significant progress in cage culture utilizing reservoir water resources. Predominant species being used are pangasius and GIFT tilapia, but trials have also been made with a genetically improved variety of rohu called “Jayanti Rohu” and with Puntius javanicus, Labeo rohita, Lates calcarifer and Macrobrachium rosenbergii. In addition, air-breathing fishes, ornamental fishes and murrels are also being cultured in cages. An overview of important species, methods and locations is presented in Table 2. Floating cages installed in Andur reservoirs at Kolhapur (Maharashtra) Fabrication of cages using locally available low cost materials in Andur reservoirs at Kolhapur (Maharashtra) TABLE 2. Typical cage culture specifics in India. Tilapia Carps Catfishes Species GIFT tilapia and Indian major carps Striped catfish and Butter catfish Red tilapia and exotic carps Murrels Locations Cochin (Kerala) Pune Chandil Maithon Pune (Maharashtra) (Maharashtra) (Jharkhand) (Jharkhand) Typical cage size 4 x 4 x 2.5 m 5 x 5 x 2.5 m 5 x 5 x 2.5 m 4m x 4m x 2m Size at stocking 25-30g 15-35g 10-25g 8-10g Feed Floating pellets Floating pellets Floating pellets Floating pellets Feed rate 3 to 5% body weight 3 to 5% body weight 3 to 5% body weight 3 to 5% body weight Culture duration 5-6 months 12 months 6 – 8 months 7 months Harvest size 500-600 g 900-1000 g 800-1000 g 50-62g