Age and growth of Cheilodactylus fuscus, a temperate rocky reef fish

To provide information on age and growth of red morwong (Cheilodactylus fuscus Castelnau), populations were sampled from eight locations over a 2.5-year period with the majority of fish sampled from six sites within Sydney Harbour, New South Wales, Australia. Transverse thin sections of otoliths taken from a total of 347 fish were used to determine age. Age estimates were validated using oxytetracycline (OTC) marking and marginal increment techniques. Validated otoliths indicated that this species forms one annulus per year over an extended period from April to October. Age varied from "0" (<1 year old) to 40 years. A comparison of otolith weight and otolith radius determined that otolith weight was the more accurate physical determinant of age. Von Bertalanffy growth estimates based on length (t(0) = -1.8, k = 0.32, L(infinity) = 37.64) indicated that growth is most rapid over the first 6 years, with fish being close to their asymptotic length by 7 years. There was no significant difference in length between sexes although females were significantly older than males. Comparisons of growth curves did not indicate any significant differences in the rate of growth between sexes.