Lakes & Coorong Fishery

The managed fisheries associated with South Australian inland waters are dominated by the River Fishery and Lakes and Coorong Fishery. The Murray–Darling Basin is the largest freshwater catchment in Australia, spanning four state-managed jurisdictions.

The system has evolved in an environment of extremes, characterised by periodic flooding and extended periods of drought. Because of its critical importance to human existence and industrial development, the entire system has been significantly modified since European settlement. The introduction of various water flow management measures, water extraction systems, the associated barriers to fish migration, and the proliferation of a number of exotic fish species have collectively served to modify the structure, productivity and function of the entire ecosystem, and has had a generally negative impact on fish habitat.

A number of the key species harvested in the Lakes and Coorong Fishery also require environmental flows down the River Murray to maintain sustainable production. The Lower Lakes ecosystem, which was originally part of Australia’s largest estuary, was modified in the early 1940s, becoming a network of shallow freshwater lakes, with golden perch, European carp and bony bream the main species harvested. The construction of a network of barrages across the five main channels near the mouth of the River Murray has also reduced the flow of water into and out of the Murray Mouth under tidal influence. The production of estuary dependent species harvested in the Coorong and along the Coorong Beach is limited during periods of minimal flow of freshwater through the barrages.

The Lower Murray Lakes and Coorong region is situated at the tail end of the Murray–Darling Basin, where the river system meets the Southern Ocean.

Production levels in the Lakes and Coorong Fishery are primarily driven by variation in natural environmental conditions, in particular the frequency of flooding and the extent of drought periods. As such, the biological productivity of most major fish species and the economic productivity of the fishery will continue to fluctuate in line with variations in natural environmental conditions such as freshwater outflows.