Some aspects of the reproductive biology of Tilapia mariae (Boulenger 1901) in a small lake in southeastern Nigeria

Some aspects of the reproductive biology of Tilapia mariae of Umuoseriche man-made lake such as fecundity of female fishes was determined gravimetrically after the sex had been established. The ratio of male to female T. mariae of Umuoseriche Lake was 1:1.56. The numbers of female fishes were greater in 110 – 145 mm and 185 – 195 mm size groups. Males dominated the 135 – 175 mm size group. Gonadosomatic index ranged between 1.4 and 3.4 with a mean of 2.25 ± 0.7. Mean ovarian weight was 1.7 ± 0.3 g and a mean fecundity of 1705 ± 629 eggs/ clutch.