Demographic analysis of scalloped hammerhead, Sphyrna lewini

Based on the mean age at first maturity t_α=5 a, longevity t_λ=15 a, average natality b=6.4·a -1, and natural mortality coefficient M=0.279·a -1, demographic analysis was used for estimating a population intrinsic increase coefficient (r₀) of 0.265·a -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. F_C at different first capture age were calculated, and relationship between F_C and t_C was fitted. The results indicated that F_C increased with the first capture age. When t_C > 5 a, the population will not decrease with capture.