Comparing Murray crayfish (Euastacus armatus) population parameters between recreationally fished and non-fished areas

The implementation of fishing regulations becomes increasingly complex where the natural state of fisheries resources is unknown. Comparing populations in fished and non-fished areas can provide information that is vital for the management and protection of species. We conducted field surveys of Euastacus armatus in non-fished and fished reservoirs and provide comparisons with a heavily fished area of the River Murray. The non-fished population (Talbingo Reservoir) of E. armatus exhibited almost equal sex ratios, robust normally-distributed population structure and a high proportion of mature and berried females. The parameters defining two fished populations (Blowering Reservoir and the River Murray) deviated significantly, to varying degrees, from the benchmark population (Talbingo). These differences suggest that recreational fishing may impose a considerable impact on the population parameters of E. armatus. Comparison with the benchmark defined in the present study will allow tracking of the population recovery under the new fishing regulations for E. armatus in the southern Murray-Darling Basin.