Buffering potency of calcium carbonate and oyster shells on the water quality for Clarias gariepinus larvae

Abstract

This study examines the buffering potency of calcium carbonate and mangrove oyster (Crassostrea gasar) shells on water acidity for Clarias gariepinus larvae. A concentration of 7.2 g for five treatments; calcium carbonate (CaCO₃) [T1], unburnt uncrushed oyster shells (UUOS) [T2], burnt uncrushed oyster shells (UCOS) [T3] burnt crushed oyster shells (BCOS) [T4] burnt uncrushed oyster shells (BUOS) [T5] and the control (C), replicated thrice, was dissolved in 10 litres of water. C. gariepinus was spawned artificially and a measured quantity of the eggs and milt were stripped into each experimental bowl. pH, temperature, dissolved oxygen (DO), calcium and total alkalinity were measured weekly for four weeks. Results obtained showed that the treatments containing shells increased the pH of the water as did the conventional calcium carbonate. T₃ and T₄ effected similar changes just as T₁ (the conventional calcium carbonate) 7.87±0.06 in increasing the water pH to 7.43±0.08 at week 1 for T₃ and 7.32±0.17 at week 1 for T₄. The mean temperature ranged from 28.33±0.5 to 30.00±1.00. The mean Calcium ranged from 16.33±0.86 to 78.77±0.18 in week 4 control and T₁ week 1.