Age, growth and mortality of the stripey, Lutjanus carponotatus (Richardson) and the brown-stripe snapper, L. vitta (Quoy and Gaimard) from the central Great Barrier Reef, Australia

The age, growth and mortality of Lutjanus carponotatus and L. vitta were determined from sectioned otoliths of fishes from the central Great Barrier Reef. The periodicity of annulus formation was validated by oxytetracycline labelling of tagged fishes in a separate study. Growth in length was variable between sexes for both species, males tending to grow larger than females. The von Bertalanffy growth function (fork length-at-age) for L. carponotatus was Lt=313.0 (1−exp {−0.449[t+0.016]}), and Lt=245.3 (1−exp {−0.853[t+0.179]}) for L. vitta. The oldest individuals found were an L. carponotatus individual of unknown sex, 20 years of age (FL=335 mm) and a female L. vitta 12 years of age (FL=257 mm). Otolith weight was strongly correlated with age for both species. The annual instantaneous rate of natural mortality (M) was estimated to be 0.199 for L. carponotatus and 0.342 for L. vitta, representing an annual survivorship of approximately 82 and 71%, respectively. The longer life span and lower rate of natural mortality for L. carponotatus indicates that this species will be more vulnerable to overfishing than L. vitta.