Seffects of hydrogen ion concentration and salinity on the survival of juvenile Clarias gariepinus (Burchel, 1822)

Abstract

Experiments were conducted to determine the effects of the interactions of two environmental parameters, pH and salinity on the survival of juvenile Clarias gariepinus (4 -12 g) under laboratory conditions. The pH values used were 3, 3.5, 4, 7 and 10 while salinity values varied thus: 0, 5 10 15 and 20 ppt in each o the pH values Three and 3 5 pH had lethal effects in all salinities. The corresponding Lt , , f . . i i i i 50 values obtained at 5 and 10 ppt were higher than those obtained at 0, 15 and 20 ppt. At 4 and 7 pH, mortalities occurred only in the higher salinities, 15 and 20 ppt. At 10 pH, Lt 50 values at salinit es 10, 15 and 20 ppt were considerably low. The lower LT 50 values recorded at 3, 3.5 and 10 pH with the higher sal nity values ndicated the lethal effects of the interactions of both parameters on fish.