Effect of Water Salinity Levels on Growth Performance and Survival of Catla Catla, Genetically Improved Labeo Rohita (Jayanti Rohu) and Cirrhinus Mrigala

In the present work, the salinity tolerance level of Indian major carp, Catla catla, genetically improved Labeo rohita (Jayanti rohu) and Cirrhinus mrigala were ascertained in terms of weight gain and mortality by exposing the fishes gradually to different levels of salinities for 45 days.Overall analysis of the result showed that, the severity of impact of increasing salinity was significantly higher (P<0.05) in Catla compared to other two species (Jayanti rohu and Mrigal).In case of C. catla significant decrease (P<0.05) in weight gain was noted from 1 ppt onwards, whereas in case of L. rohita the decrease in weight gain was found significant (P<0.05)from 3 ppt onwards and in case of C. mrigala the growth retardation was noticed from 4 ppt onwards compared to control.In case of Catla, mortality started at salinity above 5 ppt, and reached to 100% at salinity level of 8 ppt , whereas, Jayanti rohu showed no mortality up to 6 ppt salinity, though the survivability got reduced to 40% in salinity of 8 ppt.Interestingly, in case of Mrigal no mortality were recorded at salinity level up to 8 ppt on 30 days post experiment.The result obtained in the present study had given an account of the level of salinity tolerance in Indian major carps.