Inhibition of hatchability of African catfish (Clarias gariepinus) eggs on-farm by rainfall, sunshine and water stagnation

Abstract

To diagnose the impact of rainfall and temperature range on hatchability of Clarias gariepinus eggs incubated in hapas and in outdoor basins, some incubating eggs were protected against the physical impact of raindrops, some were subjected to various turbidity levels, some were protected from direct sunrays and others were incubated at various densities (number of eggs/litre of water) in flowing Vs stagnant water. Data analyses showed that, unaffected by impact of raindrops (P greater than 0.05), hatchability was inversely proportional to both turbidity (coefficient = -0.971), exposure to sunshine (P less than 0.007) and incubation density (coefficient = -0.973). Measures to ensure that on-farm incubation systems are free from turbidity, wide temperature fluctuations and anoxia, were thus highlighted as prerequired for successful incubation of Clarias gariepinus eggs.