EXECUTIVE SUMMARY BishopShortfin mako sharks were aged by counting growth bands in sectioned vertebrae collected from recreational fishing competitions and the tuna longline fishery. Replicate counts were made from images taken under reflected light. No systematic ageing bias was present within or between readers and count precision was high. Growth is rapid in early years and quickly declines. Vertebral data showed that males and females grow at similar rates until age 7-9 years, after which the relative growth of males declines. Von Bertalanffy growth parameters were: male L ∞ = 302.16 cm fork length (FL), K = 0.0524 and t 0 = -9.04 years: female L ∞ = 732.41 cm FL, K = 0.0154 and t 0 = -10.79 years. MULTIFAN analysis of length-frequency data from the tuna longline fishery estimated substantially faster growth than that derived from vertebral ages. MULTIFAN growth rates were considered reliable up to age 2-3 years, and thereafter vertebral ages were more reliable. Longevity estimates based on the maximum ages from vertebral band counts were 29 and 28 years for males and females respectively. Natural mortality estimates calculated from Hoenig's (1983) equation were 0.14 for males and 0.15 for females. Ages at 50% maturity determined by probit analysis of paired age and maturity data were 6.9 years for males and 19.1 years for females. Indirect age at maturity estimates from conversion of length at maturity data were 8-9 years for males and 20-21 years for females. Median maturity in males corresponded with the age at which male growth rate declined.The shortfin mako is a large, slow-growing, and late-maturing species with high longevity and low natural mortality. Comparison of growth curves reported here with overseas studies suggest that there are no regional differences in growth rates. Stock size and structure are unknown for this species internationally, and management should be of a precautionary nature.