Abundance and size of western rock lobster (Panulirus cygnus) as a function of benthic habitat: implications for ecosystem-based fisheries management
Ecosystem-based fisheries management (EBFM) requires the expansion of fisheries research programs to include the relationship between target species and their habitats such that trophic and other ecological interactions can be assessed. The western rock lobster (Panulirus cygnus) is an ecologically important species that supports Australia’s most valuable single-species fisheries. We tested the relationship between abundance and size of western rock lobster and benthic habitats based on the annual independent breeding stock survey and benthic towed video transects. The work was undertaken at Dongara, Jurien Bay and Lancelin, Western Australia between 2005 and 2007. Abundance of western rock lobster was significantly but moderately related to benthic habitat (adjR2 = 0.28), with high abundances associated with high cover of mixed assemblage and Ecklonia sp. Size was effectively predicted by habitat (adjR2 = 0.65) with larger lobsters found in mixed assemblages with sponge and smaller lobsters associated with mixed assemblage with Ecklonia sp. Our study has shown that understanding the influence of habitat and fishing pressure on the abundance and size of targeted species is a critical step in the effective implementation of EBFM.