International Journal of AgriScience Vol. 2(4): xxx-xxx, April 2012 www.inacj.com ISSN: 2228-6322© International Academic Journals International Journal of AgriScience Vol. 2(4): xxx-xxx, April 2012 2 Reproductive dynamics of the goldlined seabream Rhabdosargus sarba (Forsskal, 1775) from the Arabian Sea coast of Oman Mehanna S.F. *, Al-Kiyumi F. R. , Al-Kharusi L. Sahar Fahmy Mehanna, Marine Sciences and Fisheries Centre, P.O.Box 427, P.C. 100 Muscat, Oman. * Author for corespondence (email: sahar_mehanna@yahoo.com Received mmmm yyyy; accepted in revised form mmmmm yyyy ABSTRACT Goldlined seabream Rhabdosargus sarba, is a demersal sparid species along the Omani coast of the Arabian Sea and constitutes an important part of the trawl fisheries. Its maturity, spawning season, length and age at first sexual maturity and sex ratio were studied. The monthly gonado- somatic indices and macroscopically investigated maturity stages indicated that R. sarba spawns in the late autumn to the early spring from late October to early March with peak in December to February. The overall sex ratio throughout the study period was 1:0.91 males to females, which was not significantly different from 1:1. The size at 50% sexual maturity (L 50 ) was 29.6 and 28.9 cm TL for males and females respectively. It was found that about 23% of R. sarba were caught before reaching their first sexual maturity. The estimated L 50 s indicate that the current minimum legal length in Omani waters is not appropriate for managing this species. The study recommends reduction of fishing pressure especially during the spawning season and re- evaluated the mesh sizes of trawl nets used in Omani waters. Keywords: Goldlined seabream, Rhabdosargus sarba, Arabian Sea, sex ratio, spawning season, length at first sexual maturity, management INTRODUCTION Reproductive dynamics represent a crucial aspect of fish biology, stock assessment as well as fisheries management. It concerned with variation in maturity, timing of spawning, length and age at first sexual maturity, sex ratio and fecundity. Successful management strategy should consider the reproductive potential of the stock. Thus, spawning potential ratio (SPR) represents an important measure of the effect of fishing on reproductive stock and currently is used as a biological reference point for definition of recruitment over- fishing (Vaughan et al. 1992 and Goodyear 1993). As well, size at first sexual maturity (or mean length at maturity) is commonly evaluated for wild population as a point of biological reference (Hunter and Macewicz 1985, Hunter et al. 1992, Nichol and Acuna 2001, Hesp et al. 2004). Generally, description of reproductive dynamics is a key focus for stock assessment since this information is ultimately required for sound management controls such as minimum legal lengths, closed season and closed area. The goldlined seabream (Rhabdosargus sarba) is an important recreational and commercial fish species in numerous regions throughout the Indo-west Pacific (van der Elst 1988, El-Agamy 1989, Kuiter 1993, Radebe et al. 2002). It is one of the most abundant sparid species in the Arabian Sea coastal waters of Oman. It is a demersal species, caught mainly with trawl nets. Despite the importance and widespread occurrence of R. sarba, little information about its reproductive biology and dynamics