Studies on the Reproductive Biology of some Teleosts of the River Jamieson, Sapele, Nigeria.

Study of the structure of the reproductive organ of some teleost fishes in River Jamieson, Sapele, was undertaken between July and September 2009. Length and weight measurements of fishes and gonads were determined. It was observed that testes were of two structural forms, threadlike and smooth in the Cichlidae, but branched lobules in catfishes (Bagridae and Mochokidae). Ovaries were sac-like and contained telolecital eggs. The gonads depicted breeding activities. Female catfishes Chrysichthys nigrodigitatus (57.14%) Synodontis eupterus (75%) and (66.6%) were more abundant than males, while male Chromidotilapia guentheri (62.25%) exceeded females (37.50%).