Rock lobster movement patterns and population structure within a Tasmanian Marine Protected Area inform fishery and conservation management

Abstract

As reference sites to better understand characteristics such as movement patterns, depletion of natural resources and ecosystem interactions, Marine Protected Areas (MPAs) are crucial in fishery and conservation management. The southern rock lobster (Jasus edwardsii) is an important reef predator in temperate Australasia and subject to heavy exploitation. In a Tasmanian MPA, 90% of individuals were recaptured less than 200 m from the point of release over weekly to annual time scales, regardless of size or sex. This lack of movement resulted in a substantial build-up of biomass and of large mature individuals in the MPA relative to adjacent fished locations. Although there was little spillover of individuals to the fishery, a 4-fold increase in female fecundity potentially enhanced larval export. Comparison of fished and unfished biomass of legal-sized animals suggested that exploitation had reduced biomass in the adjacent fishery to <10% of natural values. Overall, the demographic and movement patterns illustrate the extent of depletion of stocks in the absence of historical baseline data and the potential need for spatial management resulting from limited movement. Our data indicate that within MPAs, this predator can potentially recover in abundance to natural levels despite adjacent fishing pressure.