Use Of Creel Survey Data To Help Recover a Native Freshwater Species In Decline, The Murray Crayfish (Euastacus armatus)

Murray crayfish Euastacus armatus are the second largest freshwater crayfish in the world, growing to 3 kg, and are a popular recreational target. The species was historically distributed throughout many rivers of the Murray Darling Basin, Australia, but have declined in abundance and size since the 1950’s. Fishing regulations, including bag and size limits, protection of berried females, and fishing closures were introduced in an effort to prevent further decline. Murray crayfish take up to eight years to reach the current minimum legal length of 100 mm occipital-carapace length (OCL). While previously the target of a commercial fishery, only recreational fisheries exist in some states. Until recently there has been no quantitative information collected to assess the recreational fishery so it has been unknown whether existing management practices are suitable. A complemented survey design was used to evaluate the 2012 Murray crayfish recreational fishery on a representative 76 km reach of the Murrumbidgee River. NSW, Australia. We found a small recreational fishery with 9,644 (± 1,580 SE) fisher hours of effort, and catch and harvest rates of 0.15 (± 0.18 SE) fish/fisher hour and 0.03 (± 0.05 SE) fish/fisher hour. These data recently contributed to a review of harvest controls and regulations were changed to increase the minimum legal limit from 90 mm OCL to a slot limit of 100 mm to 120 mm, along with further associated reductions in bag limit. Recreational harvest data were used to implement real-time management responses in this fishery. This is the first example of this type of adaptive management in a freshwater macrocrustacean fishery in Australia.