The study of reproduction of Pseudotolithus elongatus in the Ebrie lagoon was investigated between July 2013 and June 2015 on a whole of individuals of 550 specimens. the total length ranges from 14.5 to 42.7 cm. The monthly evolution of the gonado-somatic index (GSI), the liver-somatic index (LSI), the condition factor (K), the Sex-ratio, the fecundity, the diameter of eggs revealed that this species spawns throughout the year but the main breeding period was in raining season. Sex-ratio observed was in favour of females (1: 1. 14; X 2 = 2.26; p > 0.05). The percentage of mature specimens by sexes was calculated for each size class. Total length at first maturity was 21.06 cm for females and 20.21cm for males. The ripe ovaries contained 39883-814757 eggs. The relative fecundity was 216-1979 eggs per g of body weight of females. And the mean diameter of eggs is 336 ±138 microns.

This paper focuses on the threadfins Polydactylus quadrifilis, Galeoides decadactylus, and Pentanemus quinquarius captured by the maritime traditional fishing of Grand-Lahou in Côte d'Ivoire. It aims to determine their feeding habits based on weighing, measuring of body, and intestine height and identification of prey. The specimens of Polydactylus quadrifilis with height lower than 55 cm have an average of 12±1 intestinal filaments, whereas those of height higher than 100 cm have an average of 20±2 of them. This average is constant concerning Galeoides decadactylus (12±2) and Pentanemus quinquarius (11±2), for all height. The specimens of Polydactylus quadrifilis consume mainly fish (74.45%), followed by shrimps (10.06%). The juvenile ones of less than one year prefer shrimps (80.28%), whereas fish are preferred (87.07) by the older individuals. Whatever their age, Galeoides decadactylus and Pentanemus quinquarius mainly consume shrimps in the ratio of 83.11% and 68.75% respectively. The relative yearly food consumption reveals for Polydactylus quadrifilis a quantity of 0.124 T/Km2 /year, whereas that of Galeoides decadactylus is 0.02 T/Km2 /year. As for the specimens of Pentanemus quinquarius, they consume 0.013 T/Km2 /year. Threadfins have very short intestine (IC < 1) relatively to the intestinal coefficient. Their food habit is relating to stomach and intestine capabilities.

The experimentation for rearing of Polydactylus quadrifilis and Pomadasis jubelini fishes at the Layo's Experimental Aquaculture Station allowed to feed them with a food composed of 40% protein, supplemented with shrimp such as Penaeidae families (38, 4%), Palaemonidae (20%) and Aristeidae (19%). A mortality rate of 100% is observed in large specimens, while those of small size have shown high survival rates, ranging from 57%to 100%. Specific growth rates ranged from 0.9 to 2.8% for Polydactylus quadrifilis individuals and 1.1% to 2.7% for those of Pomadasis jubelini. The conversion index ranged from 1 to 2.46 for specimens of Polydactylus quadrifilis and from 0.9 to 2.2, concerning those of Pomadasis jubelini. The coefficients of variation stabilize between 11% and 17% for specimens of Polydactylus quadrfiflis, and the Pomadasis jubelini individuals have theirs stabilize between 10% and 16%. These species have aquaculture potentials to develop through a control of their breeding conditions. Problem statement and purposeIn Ivory Coast, there is no brackish water and marine fish breeded by local aquaculturists. They breed only the inland water fish, as Orechromis niloticus and Clarias. So this present study proposes to attempt the cultivation of other species from brackish and marine with aquaculture potential (Konan, 2013). Threadfin, Polydactylus quadrifilis and the white carp, Pomadasis jubelini, are tested in order to provide to aquaculturists, new productive local species and contribute to ensuring the population, self-sufficiency in fish proteins. This first phase consists in characterizing the conditions of captivity of Polydactylus quadrifilis and Pomadasis jubelini in the breeding structures of the experimental aquaculture station of the Oceanology Research Center, atLayo (Côte d'Ivoire).