Sexual maturity and fecundity of the African catfish (Clarias gariepinus) with an observation on the spawning behaviour of the Nile catfish (Clarias lazera)

Abstract

The African catfish, Clarias gariepinus, from Lakes Kariba, Mcllwaine and Kyle, was investigated for sexual maturity and fecundity. Sexual maturity is cyclical and seasonal, with a peak coinciding with the seasonal summer rains. Development from non-ripe adult fish to those in the ripe stages is shown to take less than one month. Descriptions of the stages of development are given. A line separating ripe and non-ripe groups of fish has the formula: FL=0.5 FS where FL is the number of large ova and FS is the number of small ova. The fecundity of ripe fish is related to length (total length=TL) by the cubic function F=0.04 TL (cm)^3.39 the ova have a bimodal size distribution, suggesting the possibility of multiple spawning cycles in any one year. Spawning capability is very closely related to ovary weight. Spawning behaviour in the Nile catfish, Clarias lazera, follows the pattern of C. gariepinus.

Clarias gariepinus, Clarias lazera, fecundity, sexual maturity, spawning behaviour