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 ineach o the pH values Three and 35 pH had lethal effects in all salinities.The corresponding Lt50 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, 15and 20ppt. At 10 pH, Lt50 values at salinites 10, 15 and 20 ppt were considerably low. The lower LT50 values recorded at 3, 3.5 and 10 pH with the higher salnity values ndicated the lethal effects of the interactions of both parameters on fish.

Keywords: Hydrogen ion concentration, Salinity, Survival, Clarias gariepinus