ASPECTS OF THE BIOLOGY OF SARDINELLA AURITA AND SARDINELLA MADERENSIS (CLUPEIDAE) IN THE COASTAL WATERS OF THE CENTRAL REGION, GHANA
Aspects of the biology of Sardinella aurita and Sardinella maderensis in the coastal waters of the Central Region of Ghana were investigated from October 2013 to September 2014. The study mainly provides information on the reproductive biology, recruitment pattern, growth and mortality parameters and exploitation rates of the species. FiSAT was used extensively in the estimation of the growth and mortality parameters and exploitation rates of the stocks. The overall sex ratios of both species were not statistically different from 1: 1 ratio. The lengths at 50 % sexual maturity of male and female S. aurita were estimated at 16.40 and 16.74 cm TL and that of S. maderensis were 15.43 and 15.56 cm TL respectively. S. aurita fecundity ranged from 4,834 to 63,917 whilst that of S. maderensis ranged from 7,597 to 33,984. S. aurita species spawned over 7 –8 months, with minor and major spawning seasons from February to May and July to October respectively. S. maderensis spawned over a relatively short period of 6–7 months, with a minor and major spawning season from March to May and September to October. Both species were determinate spawners producing a single batch of yolky oocytes prior to spawning. The sardines experienced recruitment throughout the year with high proportions at different periods. The stocks exhibited isometric growth. S. maderensis was found to have a faster growth rate than S. aurita with a longer life span in the latter (6 years) than the former (5 years). The sardinella stocks are not exploited sustainably. Recommendations to achieve sustainable exploitation are made.