Morphometric relationships and catch composition of wobbegong sharks (Chondrichthyes: Orectolobus) commercially fished in New South Wales, Australia
Huveneers, C., Otway, N.M. and Harcourt, R.G., 2007. Morphometric relationships and catch composition of wobbegong sharks (Chondrichthyes: Orectolobus) commercially fished in New South Wales, Australia. Proceedings of the Linnean Society of NSW, 128: 243–249.
Three species of wobbegongs: the spotted wobbegong, Orectolobus maculatus, the dwarf ornate wobbegong, O. ornatus, and the large ornate wobbegong, O. halei occur in coastal waters off New South Wales (NSW), Australia. Wobbegongs are bottom-dwelling sharks and have been targeted primarily by commercial fishers operating in the NSW Ocean Trap and Line fishery. The flesh of wobbegongs is considered to be ‘good-eating’ and is sold as boneless fillets or ‘flake.’ The catches of wobbegongs have declined by approximately 60% over a decade and this has led to concerns over the ecological sustainability of their continued harvest. Currently, the length and weight composition of the catch is unknown as carcasses are trunked (i.e., beheaded and eviscerated) before landing. This study provided data to examine length-length, weight-weight and weight-length relationships and to convert carcass length and carcass weight measurements to total lengths and total weights for subsequent use in fisheries assessments. The females of all three species of wobbegong had greater body weights compared to males for any given length. Sex-based differences in body weight are often due to discrepancies in the weights of internal organs and are common in sharks and rays. Female sharks usually have larger livers and reproductive organs and these probably accounted for the observed differences in weight. New-born sharks and small juveniles were conspicuously absent from the length-frequency distributions of all three species, suggesting the potential existence of nursery areas not targeted by the commercial fishery.