Artifical Reefs Do Boost Fish Stocks

4 months after installation. Photo: UNSW Science

Anglers have long known the importance of structure and it’s appeal to fish. In pursuit of enhancing fishing in our marine and estuaries, VRFish is supporting an expansion of purpose-built reefs to create new fishing opportunities and improve fish habitat.

What has been a hurdle and a point of contention with some decision-makers and purists is these structures merely attract fish from other areas.

Latest research from the University of New South Wales has now debunked this theory and shown artificial reefs can boost fish abundance in estuaries with little natural reef.

Three estuaries were chosen for the study, Lake Macquarie, Botany Bay and St Georges Basin, as they are recreational fishing havens. Commercial fishing was removed from these estuaries in the early 2000’s. Each of the estuaries were created with sand and as such, don’t have much natural reef in the area.

Researchers installed human made reefs into each estuary. The reefs were made up of 180 commercially made concrete domes with holes. The domes were divided into six reefs consisting of 30 domes. Each of the domes measured 0.7m in diameter and 0.5m in height. The domes were placed on top of bare sand. Since the conclusion of the study, larger units, up to 1.5m in diameter, have been installed in estuaries across the state.

Fish find the reef balls reefs more appealing than bare sand as they improve the water flow around the reefs and provide protection for fish. The artificial reefs create the perfect rocky habitat for juveniles which can enable more fish to survive after entering the estuaries.

Researchers monitored the fish populations for three months before installing the reefs, one year and two years afterwards. A wide variety of fish were observed using the reefs and species such as snapper, bream and tarwhine increased up to five times. Overall, up to 20 times more fish were observed compared to before the reefs were installed.

There was also an increase of fish abundance on the nearby natural reefs. Researchers also noted that there was no evidence that fish had come from neighbouring natural reefs to the artificial reefs. In fact, they noted abundance had increased in the natural and artificial reefs, suggesting that fish numbers were overall increasing in the estuary.

The study was recently published in the Journal of Applied Ecology and funded by the NSW recreational fishing trust. Read the Science Daily article here.

Back to Victoria, the Victorian Government is investing $2.5 million into news reefs for Port Phillip Bay, with some of these funds allocated to expanding our living shellfish reefs.

There are already a number of artificial reefs that have been deployed across the state including Torquay, Port Phillip Bay and East Gippsland. The locations of the reefs can be found on our website via Artificial Reefs. There are many more untapped opportunities across Victoria and artificial reef installations are good news for jobs and regional development.

As we look to new opportunities here in Victoria, the study has demonstrated the importance of monitoring these reef structures and collecting data to demonstrate their contribution to fishing and fish stocks. VRFish knows that our fishers can take a lead role with monitoring and data collection.

With the burgeoning citizen science movement, anglers in other states are leading way with monitoring programs using baited remote underwater cameras. Recfishwest’s Reef Vision program now runs statewide in Western Australia with 34,000 individual fish across 79 species recorded from their artificial reef installations – and still counting. Check out the footage of Exmouth’s King Reef below.

Fish Populations Booming on Exmouth’s King Reef

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