Age, growth and maturity of a New Zealand endemic shark (Mustelus lenticulatus) estimated from vertebral bands

Rig (Mustelus lenticulatus) specimens were aged by counting growth bands in whole vertebrae that were illuminated laterally with fibre-optic lights. B ands were counted by two readers who used information on the diameter of th e vertebrae of new-born young and 1-year-old juveniles to identify the inne r bands. The greatest estimated age was 12.1 years for a female of 137 cm t otal length, but few rig were more than 8 years old. For west coast South I sland (WCSI) rig, there was no significant difference in growth rates of ma les and females. After pooling both sexes, there was no significant differe nce in growth rates between WCSI and east coast South Island (ECSI) rig. Th e combined WCSI and ECSI von Bertalanffy growth curve was L-t = 147.2 (1 - e(-0.119[t + 2.35])). This curve agreed well with growth curves derived fro m length-frequency data, but validation of the ageing technique is still re quired. WCSI males mature at similar to 85 cm and 5-6 years, and females at similar to 100 cm and 7-8 years. ECSI rig probably mature at similar lengt hs and ages. Tagged rig have been recaptured after nearly 14 years at liber ty. Longevity probably exceeds 15 years, and may exceed 20 years.