COMPARATIVE STUDY OF SPAWN PERFORMANCE OF THREE WILD POPULATIONS OF OREOCHROMISNILOTICUS (LINNAEUS, 1758) FROM MONO BASININ BENIN

This study aims to assess the spawn performance of three populations of O. niloticus collected in Sohoumè, Nangbéto and Togbadji stations of Mono basin. By population, wild spawners were collected and distributed separately in two tanks, one containing ten females and the other five males. The male was brought into the females’ tank. At each spawning, the eggs were collected, measured and the laying female was tagged and returned to the tank. For the three populations, the average total weight of eggs, average absolute fecundity, average relative fecundity, and average gonado-somatic index per population ranged respectively from 8.6 ± 3 to 9.6 ± 1.7 g ; 1304 ± 323.1 to 1402 ± 371.4 eggs; 4.7 ± 1.6 to 6.4 ± 1.2 eggs / g of female and 3 ± 1.2 to 4.4 ± 1.8% without significant differences. Diameter of the eggs varied significantly (P ? 0.01) from 1.9 ± 0.2 to 2.2 ± 0.4 mm between the three populations with the population of Togbadji which thus, displays the best performance of spawning.