The reproductive activities of a small Cichlid Chromidotilapia guntheri were investigated from July 2003 to March 2005 in four coastal rivers (Ehania, Eholié, Noé and Soumié), in the southeast of Côte d’Ivoire. Trends in gonadosomatic indices and reproductive stages of development suggested that C. guntheri is a multiple (fractional) spawner and breeds all year round with little fluctuation in spawning intensity. However, spawning activities were more intensive in August and September. The estimated mean standard length at first maturity did not differ significantly between rivers. It was, in the overall population, 85.53 mm SL for males and 100.13 mm SL for females. In general, the sex ratio differed from 1:1 with the predominance of the males in rivers, standard length classes, seasons and the entire population. Absolute fecundity (F) varied from a minimum of 70 to a maximum of 470 eggs. The range of variation in the relative fecundity was from 3066 to 9135 eggs per kilogram of fish in the total population. Fecundity did not differ extensively between rivers. The absolute fecundity relations to fish standard length (SL) and eviscerated weight (We) were best described in the whole population by the following equations: F = 0.00069 × SL2.72 and F = 2.54 × We1.15, respectively. Moreover, there was no relationship between absolute fecundity and oocyte diameter.
Auteurs du document :
C.K. Boussou, Edia O. Edia, Felix K. Konan, Mamadou Ouattara, Allassane Ouattara, Germain Gourène
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Mots clés :
spawning activities, Ivorian coastal streams, activités de reproduction, rivières côtières de Côte d’Ivoire