Salinity tolerance of Rohu (Labeo rohita) and its hybrid under differenttemperature regimes

An experiment was carried out at Fisheries Research Farms, University of Agriculture, Faisalabad, in order to find out the tolerance of Rohu (Labeo rohita) and its Hybrid (Labeo rohita ♂ x Catla catla ♀) for different levels of salinity under three temperature gradients. The salinity levels were prepared on the basis of electrical conductivity (E.C.), by adding commercial grade NaCl in the water. The five experimented EC levels were 1.2 mS/cm for control, 5, 10, 15 and 20 mS/cm for treatment T1-T4, respectively. The selected temperature gradients were 14, 21 and 28C. The 7-days LC-50 values for rohu were remained as 17.383, 19.649 and 10.158 mS/cm at temperature 14, 21 and 28C, respectively, while the 7-days LC-50 values for its hybrid remained as 20.465, 11.640 and 8.352 mS/cm at temperature 14, 21 and 28C, respectively. Hybrid showed more susceptibility towards salinity as the temperature rises. Rohu proved to be more resistant against salinity at high temperature than low temperatures. The important physico-chemical parameters varied significantly but remained favorable during the whole period of study.