The Herpetological Journal

pp.1-8

Authors: S. M. Siddeek And R. M. Baldwin

Abstract: We applied the stage-class matrix model to published data to investigate the population growth rate of Oman female green turtles (Chelonia mydas) under different simulated biological and fishery conditions. Juveniles dominated the stable stage-class population vector. Juveniles and adults contributed most to the potential reproductive output. The present total fishing deaths consisted of approximately 2280 hunted and 2000 accidentally drowned (in fishing nets) female turtles. The model suggested a maximum hunting quota of approximately 1 43 females to maintain a stable population. In addition to protecting eggs and hatchlings, reduction in the juvenile mortality significantly increased the population growth rate. Simulated reduction in the current annual 4280 female fishing deaths to 268 produced a positive population growth rate within feasible stock parameter values. Previous studies have indicated a size at first maturity below 85 cm curved carapace length (CCL). Thus, restricting the number of hunting and accidental drowning deaths to less than 268 females and enforcing a minimum size limit of 85 cm CCL in the traditional turtle fishery appeared necessary to reverse the population decline. More studies on stock abundance, sex composition, stage specific growth, survival, and reproductive rates are needed to refine the model.