Abstract:
The reproductive activities of the male and female black promfret parastromateus niger in Kuwaiti waters were investigated from October, 2003 to September, 2005. Analysis of seasonal variations in the gonadosomatic index (GSI) during the two-year study period revealed high values from February to September, suggesting that the black pomfret has a prolonged spawning season, from February to September, suggesting that the black pomfret has a prolonged spawning season, from February to September. GSI fluctuations correlated positively with rising water temperatures in Kuwait from low values in both parameters in January to high values in February/March (r = 0.836, p < 0.05) for males and r = 0.764, p < 0.05 for females), suggesting that temperature plays a role in triggering spawning in both the sexes. Analysis of seasonal distribution of maturity stages for the two years revealed the presence of ripe/running males and females from February to September, thus confirming the spawning periodicity revealed through the analysis of fluctuations in the GSL. Macroscopic and microscopic studies of maturity stages revealed six stages in the males and seven in the females. The logistic function based on pooled data for the two years revealed that the minimum size at sexual maturity (L50) was attained at a size of 30.9 cm SL in males (r2 = 0.284) and 36.5 cam SL in females (r2 = 9.355). The ratio of males to females in monthly samples did not depart significantly from the hypothetical 1:1 during the entire study period (÷ 2 = 61.9, d.f. = 11, p < 0.05). Total fecundity ranged from 71 305 in a fish measuring 39.8 cm SL and weighing 1 572.5 g to 3.895 in a 49 cm SL and 3 630 g fish, with a mean of 1 216.734 eggs. Positive correlations were found between fecundity and ovary-free body weight standard length and ovary weight, and a negative one with egg size. The average relative fecundity was 948 eggs/g ovary-free body weights, which was neither a function of fish standard length nor ovary-free body weight.