Catfish Mystus Vittatus Research Articles

Toxic and sublethal effects of carbaryl on a freshwater catfish, Mystus vittatus (Bloch).

The effects of carbaryl (1-naphthalenyl methylcarbamate), commonly used in agricultural operations, have been studied with reference to survival, behavior, food intake, growth, and conversion efficiency of the catfish Mystus vittatus. At a concentration of 32.5 ppm, carbaryl caused 100% mortality within 24 hr; the 72 hr LC50 was 17.5 ppm. At concentrations of 12.5 ppm and below, it caused no mortalities within 72 hr. But such sublethal concentrations accelerated the swimming activity and increased the frequency of opercular beats. The latter response was dose-dependent. These behavioral changes were the immediate response to the toxicant and were indicators of possible stress. A 27-day exposure to sublethal concentrations of carbaryl led to a decrease in feeding rate and growth rate. The latter decreased from 10.15 mg/g/day (freshwater) to 2.84 mg/g/day (12.5 ppm). The reduced growth and conversion efficiency may be due to the expenditure of more energy for the purpose of maintenance. Therefore, the insecticide is considered to be a metabolic stressor.

Food intake, growth, food conversion, and body composition of catfish exposed to different salinities

The effects of different salinities (0, 2, 4, 6 and 10‰) on food intake, growth, food conversion, and body composition of the freshwater catfish Mystus vittatus (Bloch) were studied. Under a restricted feeding schedule daily intake of food was found to be salinity dependent. Fish reared in 10‰ consumed more Tubifex tubifex, converted less efficiently and displayed poor growth as compared to individuals reared in fresh water. Fish flesh production decreased from 483 g (fresh water) to 177 g (10‰ salinity) as the salinity was increased. Water content of the fish was found to decrease with increase in salinity, while maximum ash (25.56%) and fat (42.25%) were exhibited by fish reared in 10‰ salinity.