THE FECUNDITY OF GERRES OYENA FORSKAL 1775, ( FAM. GERREIDAE) IN THE QATARI WATERS OF THE ARABIAN GULF

ABSTRACf Fecundity estimates were made on a total of 180 mature fish Gerres oyena Forskal of different lengths and weights, collected during the early spring of 1985. Log -log relationships were estimated between fecundity (either absolute or relative ) and fish length, weight, age and ovary weight. It was found that, absolute fecundity increased at a rate proportional to the power of 5.47, 1.79, 1.78 and 1.08 of the total length, the body weight, the age and the ovary weight, respectively. Results showed that fecundity, either absolute or relative, depended mainly on body length and to a lesser extent on body weight, fish age and ovary weight. Therefore, length is the best expression for fish fecundity and can be used for the prediction of Gerres oyena production in the Arabian Gulf waters. INTRODUCfiON The Arabian Gulf is an important aquatic resource in Qatar, yet its fisheries are considered to be still virgin. Gerres oyena Forskal, is a widely distributed and economically important marine fish which is capable of adapting itself to diverse climatic conditions ( ranging from tropical to temperate seas ) or over nearly all the world ( Kuronuma and Abe 1972 ). Successful exploitation of any fish requires a thorough knowledge of its reproductive biology. In view of the considerable variations reported in gonadal cycle, knowledge about spawning season and fecundity is urgently needed in order to maintain and manage this important fish species.