The effects of western rock lobster fishing on the deepwater ecosystems off the west coast of Western Australia
Department of Primary Industries and Regional Development (DPIRD) WA
The Scientific Reference Group (SRG), including Drs Alistar Robertson, Simon Thrush, Andrew Heyward, John Keesing, Colin Buxton, Chris Simpson and Jim Penn, was formed as an independent body to provide advice on research directions, to examine the effects of western rock lobster fishing on the ecosystem. The SRG identified that there is a major gap in the understanding of the interactions between the rock lobster fishery and the ecosystem in deep water. Although significant data is available on the shallow (<40 m) water ecology of lobsters and the fishing impact there is gap in the knowledge of the deep-water ecology of lobster. They recognised that the major change in abundance and size structure of the western rock lobster population would have occurred in deep water (40-100 m), and concluded this was a priority area of research. There is a need to collect basic ecological information to determine if changes in lobster density and size structure,due to fishing has caused significant changes in habitat structure and benthic community composition in deep water. This will provide information on the level of ecosystem impact of removing lobsters from deep-water habitats to improve the assessment of risk to the ecosystem to ensure that the western rock lobster fishery maintains MSC certification and complies with DEH requirements for export permits. However, the SRG recognised that research needs to occur in a structured manner and have highlighted the need for research proposals which sit within the strategic framework which they have devised. The SRG recognises that the provision of a strategic framework and related scientific research will ultimately allow management of deep-water stocks in a more sophisticated ecosystem-based manner.
1. To identify gradients in the density/size distribution of western rock lobster to enable selection of representative areas.
2. To assess the catchability of western rock lobster and its relationship with population abundance and size structure
3. To identify the relationship between the deep-water habitat and the density/size distribution of western rock lobster to enable a preliminary evaluation of the impact of lobster biomass removal in the deep-water
Principal Investigator: L. Bellchambers
Key Words: Western Rock Lobster, density, size, distribution, population, deepwater