Abstract:
Stinging catfish (Heteropneustes fossilis) is very popular in Bangladesh. It has high market value. A number of attempts have been taken in different study to develop culture systems of this fishes in cages but the survivability and growth rate was not satisfactory which ultimately decreased production. In the present study, attempt has been taken to develop sustainable cage culture technique providing natural environment for the species inside cage to increase survival rate as well as production. For this purpose, mud with hanging plastic pipe substrate was provided inside the cages since the fish naturally dwell in the mud and prefer to hide inside substrate. Survival and growth of fish inside such modified cage were compared with the fishes reared in ordinary cage. The experiment was conducted for a period of 150 days. Fish fries with a mean weight and length ranged from 2.02 to 2.72 g and 6.30 to 7.28 cm respectively were stocked at 100 and 150 fish per m3 floating cage with eight treatments and two replicates each in a large earthen pond at Sher-e-Bangla Agricultural University (SAU) campus, Dhaka. Commercial pelleted feed was supplied to caged fish twice daily at a rate of 50% body weight initially per day and later feeding rate was adjusted based on body weight by sampling. Important water quality parameters (temperature, DO, pH, transparency, ammonia, phosphate and nitrate) were recorded weekly throughout the culture period. Survival was 82.50% and 73.67% in the modified square shaped cages and 43.0% and 54.67% in modified rectangular shaped cages for the density of 100 and 150 fish per m3 respectively. Mean final weight were 24.34g and 32.32g in the modified square shaped cages and 24.84g and 24.55 in the modified rectangular shaped cages for the stocking density of 100 and 150 fish per m3 respectively. In case of ordinary cages, survival was only 57.0% and 52.33% in the square shaped cages and 40.0% and 34.67% in the rectangular shaped cages for the density of 100 and 150 fish per m3 respectively. The mean final weights were 17.63g and 18.66g in the square shaped cages, and 15.16g and 16.40g in the rectangular shaped cages for those stocking density respectively. Results showed that net yield was relatively higher in modified square shaped cages than that of ordinary and rectangular shaped cages. This experiment demonstrated the potential of H. fossilis production through new technique of cage culture system. However, more research is needed using local feed ingredients with higher stocking density, and also setting mud and substrate separately inside cage to increase profitability and efficiency of the culture system.
