The effect of day length on induced breeding of Clarias gariepinus (Burchell, 1822)

Abstract

Monthly-induced breeding of Clarias gariepinus was carried out for the period of mornings (0800-0900h), afternoons (1300-1400 h) and evenings (1700-1800 h) from May to August 2000. Results showed that mean relative fecundity realized in the evening were significantly higher than morning (p< 0.05). Mean percentage hatching of spawned eggs showed significant difference in values of evenings and mornings, as well as afternoons and mornings (p< 0.05). However, there were no significant differences in the values of fry survival. Mean water temperature for morning inducements was 25±0.020C, afternoon 28.5±0.180C and evening 29±0.180C. The variations in the value of products of induced breeding for the three different day length periods were attributed to the important role of temperature and photoperiodicity in the reproductive biology of fish.

Keywords: Fish; Clarias gariepinus; day length; induced breeding

Animal Production Research Advances Vol. 2 (3) 2006: pp. 155-157