Studies on southern Australian abalone (Genus Haliotis). IV. Growth of H. laevigata and H. ruber

Abstract

The growth of H. laevigata Donovan and H. ruber Leach was studied at several sites in South Australia by fitting the von Bertalanffy growth equation to growth data, supplemented by analysis of length- frequency distributions. Juvenile individuals of H. laevigata grow at an average rate of 0.9 mm per week, reaching a length of about 40 mm in 1 year at West Island; at Waterloo Bay H. laevigata can reach a length of 50 mm in the first year. After the first year, the annual growth coefficient (K) and the asymptotic length (L∞) for the two species at three sites are, respectively: H. laevigata-0.48 year-1 and 138 mm (West I.); 0.41 year-1 and 131 mm (Tipara Reef); 0.59 year-1 and 148 mm (Waterloo Bay); H, ruber-0 34 year-1 and 139 mm (West I.); 0.32 year-1 and 143 mm (Tipara Reef); 0 41 year-1 and 144 mm (Waterloo Bay). There are also seasonal differences in growth rate between species and between sites. These differences as well as differences in the annual growth rate within a species between sites are associated predominantly with differences in the food supply. There is differential growth between the sexes of H. laevigata at Waterloo Bay, where females grow 25% faster than males and reach a larger size.