Reproductive biology of Oreochromis niloticus in Lake Beseka, Ethiopia

Abstract

Reproductive biology of Oreochromis niloticus in Beseka was studied. Samples of O. niloticus were collected monthly during September 2010 to August 2011 using different centimeter mesh sizes of gillnets. The relationship between total length and total weight was curvilinear and sex ratio was different throughout the sampling periods. The 50% sexual maturity length (L50) was estimated at 14 cm TL for females and 17 cm TL for males. Estimated fecundity was linearly related with total length and total weight of the fish. Absolute fecundity was estimated in number and range from 125 to 251 with a mean of 161±2.5. The frequency of ripe gonads suggested that O. niloticus in Lake Beseka breeds throughout the year and intensive breeding coincided with the rainy seasons.