AGE AND GROWTH OF NEW-ZEALAND SCHOOL SHARK, GALEORHINUS-GALEUS

School shark, Galeorhinus galeus (family Triakidae), are fished commer cially throughout New Zealand, and estimates of their growth rate, age at maturity, and longevity are required for fishery management. We ag ed school shark from X-rays of thin vertebral sections, but many secti ons were unclear and ageing precision was low. Nevertheless, there was no between-reader bias, and growth curves derived from length-at-age data appear robust. A growth curve was derived independently from leng th-frequency data for juvenile school shark up to 9 years old and 120 cm long, and it agreed well with the curve derived from length-at-age data. For older sharks, the growth rate is not certain because of smal l sample sizes and lack of validation of the ages. Growth rate estimat es from tag-recapture data suggested faster growth for small sharks an d slower growth for large sharks. Based on length-at-age data, males a nd females grew at about the same rates. Males matured at about 12-17 years and females at about 13-15 years. The oldest shark in our sample s was estimated to be 25 years old, but few large sharks were availabl e for ageing so the longevity of New Zealand school shark remains unce rtain.