Aspect of reproductive biology of the cassava croaker, Pseudotolithus senegalensis (valenciennes, 1833) of Ivory coast continental shelf

Abstract

From January to December 2014, some aspects of Pseudotolithus senegalensis reproductive biology in Ivory coast were investigated and focused on sex ratio, gonadosomatic and liver-somatic index, size at first maturity, stages of gonadal development and fecundity. A total of 696 fish with body length of 12 to 36 cm standard length (SL) and body weight of 25. 2 to 675.1 g were used for this study. The sex ratio of P. senegalensis was 1: 0.5 (male to female). The females were more than the males (x 2 0,05 (1) = 51.36; p< 0,05). Males and females reach first maturity at 19.01 and 22.28 cm SL respectively. The monthly variations of the gonadosomatic index (GSI), hepatosomatic index (HIS) and the condition factor (K) indicated two periods of reproduction. The long period and the short period were respectively from March to June and from September to November. The hepatic reserves seem to be mobilized to ensure the energetic cost of the reproduction. The absolute Fecundity was ranged from 78612 to 140946 eggs and was positively correlated with standard length and weight. Fecundity-length and fecundity-weight relationships showed positive correlations. The fecundity-length and fecundity-weight relationships were determined by regression analysis with the regression equation F= 12.820xSL– 321.70 (r=0.99) for fecundity-length and F= 0.27xTW – 46.66 (r=0.98) for fecundity-weigth relationship.