Demographic analysis of scalloped hammerhead, Sphyrna lewini

Based on the mean age at first maturity t=5 a, longevity t=15 a, average natality b=6.4a-1, and natural mortality coefficient M=0.279a-1, demographic analysis was used for estimating a population intrinsic increase coefficient (r0) of 0.265a-1, a reproductive rate per generation (R0) of 6.212, a generation time (G) of 7.571 years and a population doubling time of 2.616 years under unfished. Demographic parameters such as r0 affected by M were discussed Fc at different first capture age were calculated, and relationship between Fc andtc was fitted. The results indicated that Fc increased with the first capture age. When tc5 a, the population will not decrease with capture.