Better fish habitat in lakes - lessons from overseas

Dr Andrew Norris

Senior Fisheries Biologist, Queensland Department of Agriculture and Fisheries

The availability of habitat is essential to fish for foraging, shelter and reproduction. In many dams, vegetation and timber are cleared prior to initial flooding, leaving limited structural complexity for fish. The quality of remaining habitat also declines greatly as dams age and can lead to poor fisheries and poor angling. Habitat enhancement has the potential to slow or reverse this trend and improve the fishing.

Habitat enhancement in impoundments has been widely practised around the world to improve fisheries by increasing productivity, carrying capacity, reproduction, survival and growth. Installed habitat structures can also significantly improve angling by attracting fish to locations that anglers can more easily access or target, leading to larger and more reliable catches. This approach is undertaken by almost all state fisheries agencies in the USA.

A wide variety of habitat enhancement methods have been employed to improve habitat complexity in USA reservoirs and lakes. Habitat enhancement have been used to aggregate fish, provide more food, increase growth rates, improve reproductive success, improve juvenile survival and recruitment (wild and stocked), and provide protection from predators.

"Habitat enhancement has made it a lot easier for tourists to come and fish and increased the likelihood of them catching something." Stacey King, professional tournament angler and guide.

Historically the materials used for fish attracting structures have largely been those that are convenient, economic and readily available. As knowledge in the field grows, more specialist fish attracting structures are being created to service specific needs of different species and size classes. Generally a combination of fish attracting structure types is utilized to provide greater diversity of habitats for a wide range of species. Many of the techniques are suitable for construction and deployment by community groups such as angling clubs, and can be cost-effectively implemented.

This presentation discussed some of the techniques that have been used successfully in the USA and how they could be applied in Australia to improve dam fisheries.

Man holding big cod our best Murray cod fishery
Fish attracting structures should work for our native species as well!
a new dam
Much better fish habitat in a new dam
an old dam
Typical poor fish habitat in an old dam
Brush Pile
A brush pile which has attracted a variety of fish of different sizes and species
Synthetic Georgian cube
A synthetic Georgian cube used to attract fish