Weight-length relationships, gonadosomatic indeces, sex ratios and relative weight of the Omani-Indian Oil sardine, Sardinella longiceps (Valenciennes 1847) from Al-Seeb area; Sultanate of Oman

This study presents the weight-length relationship and spawning period of the Omani Indian Oil sardine Sardinella longiceps (Valenciennes 1847) which inhabits the near shore zone along the Omani coast. A total of 1744 specimens were collected between January 1997 to February 1998 from Al-Seeb; a suburban area situated by the sea in Muscat, Oman. Samples were obtained on a monthly basis from beach seine and gillnet catches. The female to male sex ratio was obtained to be 0.6. The monthly variation in the gonadosomatic indexes indicates that the fish spawn in March; August and February. The overall length-weight relationships were found to be W = (8.13×10 ^-6)×L ³ W = (9.07×10 ^-6)×L ³; and for the W = (8.43×10 ^-6)×L ³combined sexes; female; and male; respectively. The length at which 50% of the sardines were estimated to be 172 mm (43.48 g) for the combined sexes; 169 mm (41.3 kg) for females; and 167 mm (39.74 g) formales.