Reproduction and natural mortality of Polynemids (Polydactylus quadrifilis, Galeoides decadactylus and Pentanemus quinquarius) have been study through weighing and the catches of sizes of those caught by the marine artisanal fishermen in Grand Lahou (Côte d’Ivoire).
Study of the monthly variations of gonado-somatic-idex (GIS) showed that the threadfins recur during the dry season, from november to march. Those of liver-somatic-index (LSI) and factor condition (K) indicated that these fishes use their liver and muscles reserves to develop gonad. Length at first maturity was estimated based on the P logistic model. The Polynemids die massively during the raining season (april to october), which constitute the cold periods of the year.