Growth, mortality and yield per recruit of the king soldier bream Argyrops spinifer (Sparidae) from the Oman coast of the Arabian Sea

The King soldier bream Argyrops spinifer at Arabian Sea (Omani waters) was assessed using Beverton and Holt yield per recruit model. A total of 5520 specimens were collected during five trawl surveys between September 2007 and August 2008. The maximum life span was 11 years for length range of 11.0 – 62.1 cm TL. The von Bertalanffy growth parameters were K = 0.22 year^-1, L∞ = 65.51 cm, to = -0.75 year and W∞ = 5430g. The rates of total mortality Z, natural mortality M and fishing mortality F were 0.85, 0.26 and 0.59 year^-1 respectively. The exploitation ratio E was 0.69 indicating the high level of exploitation. The estimated total length at 50% maturity was 31.8 cm. Yield per recruit analysis revealed over-fished stock conditions particularly because small fish are effectively unprotected by current minimum size regulations. Therefore measures such as closed seasons or changes in fishing patterns would be desirable to safeguard the spawning stock and recruits. Also, the commercial fishery of Arabian Sea, Oman should be subjected to a total allowable catch and a maximum size limit be implemented

Precision of Age Estimation in Goldlined Seabream Rhabdosargus sarba (Sparidae) from the Arabian Sea, Oman

Accurate age determination of commercial fish is vital to successful fisheries management. Reliable age determination is essential for almost all aspects of fishery research, especially for study of growth, production, population structure and dynamics. The validation of aging methods is an important step in estimating growth and longevity. This study presents the validation of otolith-reading method for age estimation of goldlined seabream Rhabdosargus sarba. A total of 1185 goldlined seabream otoliths collected from the Arabian Sea of which 350 specimens were read by two different readers for whole and sectioned otoliths. Age comparisons between whole and thin-sectioned otoliths showed agreement in age readings for age groups 2-5 years and the whole otoliths tended to give lower ages than those estimated by thin sections. APE ranged from 3 to 7% for the three readings. Common differences between readers were related to interpretation of the otolith edge type and to interpretation of the first annulus. Keywords: Sparidae, Rhabdosargus sarba, Otolith; age; average percent error; management