Some reproductive traits of three fish species from Lake Ayamé 1 of the South-Eastern Côte d’Ivoire

Abstract

This study was carried out to update some data on reproductive parameters of Sarotherodon melanotheron (n = 617), Chrysichthys nigrodigitatus (n = 545) and Brycinus macrolepidotus (n = 498) from Lake Ayamé 1. Samples were collected on monthly basis, between September 2017 and August 2018 using gillnets of various sizes. Based on gonadosomatic index (GSI) and maturity stages, S. melanotheron and B. macrolepidotus exhibited two spawning periods while C. nigrodigitatus reproduced during a single period, which coincided with the rainy seasons (March to July and October to November). In S. melanotheron and C. nigrodigitatus, males reached the first sexual maturity size (SL₅₀) at smaller length than female with the SL50 obtained are lower than those observed in the same lake or in other ecosystems. Absolute fecundity is positively related to standard length and body weight. Relative fecundity ranged from 1 to 294 oocytes per g of body weight in these species and the trend of increasing of fecundity was observed reflecting a possible adaptation to fishing pressures.

Keywords: Fish, size, fecundity, gonadosomatic index, ovary maturity, Lake Ayamé 1.