Impact of various fertilization techniques on the hatchability and survival of the African catfish Clarias gariepinus (Burchell, 1882)

Abstract

Egg fertilization is a major factor in successful catfish fry-fingerling multiplication. This study was therefore conducted to evaluate the three methods of fertilization on hatchability and survival of Clarias gariepinus brooder eggs. The methods examined in this study were the Dry Method (DM) with 1800 eggs and 2.0 ml of sperm, Wet Method I (WM1) with 1800 eggs, 2.0 ml sperm, and 5.0 ml normal saline, and Wet Method II (WMII) with 1800 eggs, 2.0 ml sperm, 5 ml normal saline and 10.0 ml water. The temperature, pH, dissolved oxygen (DO), and conductivity were measured using standard instruments. Data were analyzed using one-way analysis of variance. Early hatching was observed at 17.2 hrs in DM and was significantly (P<0.05) lower than in other methods. The highest fertilization rate (82.6%), hatching rate (74.8%), and survival rate (81.8%) were observed in DM and differed significantly (P<0.05) from the values in other methods. All physicochemical parameters in the methods showed no significant difference (P>0.05), except for a significantly (P<0.05) higher temperature of 28.69± 0.43°C in DM. An increase in temperature must have contributed to the overall positive results in DM; thus, DM was the most effective method among the tested.