Port Phillip Bay Shellfish Reef Restoration Project

The Port Phillip Bay Shellfish Reef Restoration Project is part of an Australia-wide Reef Builder initiative (click here for more: https://www.natureaustralia.org.au/what-we-do/our-priorities/oceans/ocean-stories/reefbuilder/), led by The Nature Conservancy, to restore a marine ecosystem back from the brink of extinction. Port Phillip Bay, similar to other bays and estuaries in Victoria, once supported extensive natural oyster and mussels reefs, that supported a huge range of other sea life, including many fish species. Due to over exploitation compounded by catchment coast pollution and other factors, these shellfish reefs have largely disappeared.

In 2015, in an Australian first, The Nature Conservancy joined forces with the Victorian Government and the Albert Park Yachting and Angling Club to rebuild Port Phillip Bay’s lost shellfish reefs. This foundation partnership has since flourished to include many other partners and supporters.

The project has taken a staged approach to restoration, following the standards and principles of the Society of Ecological Restoration, combined with The Nature Conservancy’s twenty-five years of international experience of restoring shellfish reefs. To date, they have restored 5.5 hectares of shellfish reefs in Port Phillip Bay, including 1 hectare in Dromana in 2020. 

Map of Port Phillip Bay which includes the shellfish reef restoration sites and historical extent of shellfish reefs

The Dromana site was chosen through an extensive site selection process, involving observational surveys, Restoration Suitability Modelling, further towed video surveys by a consultant and baseline scientific monitoring. During these surveys previously unmapped seagrass beds were found which have now been added to the state-wide biotope database.  The shellfish reef restoration site shows strong evidence of being an old shellfish reef and is in 8 to 9m of water. There is a 350m buffer to the nearest seagrass bed. All necessary permits have been secured from the Victorian Government to undertake these restoration works. 

TNC diver showing an old Australian flat oyster shell from the Dromana shellfish reef restoration site. Photo: The Nature Conservancy

The restoration process first involves rebuilding a reef base using limestone rubble, then seeding the new base with hatchery reared Australian flat oysters and blue mussels grown out by an aquaculture farmer. These new reefs will be monitored each year to track survival and growth of the shellfish and changes in biodiversity overtime (e.g. fish) based on our Monitoring, Evaluation and Reporting Plan.

 

Image of reef construction work in full swing at Dromana, with Long reach excavator deploying limestone rubble from a barge.  Photo: The Nature Conservancy

There are more shellfish reefs planned to be restored in Port Phillip Bay in 2021, including at the Dromana site. To find out more information and about volunteer opportunities, please visit The Nature Conservancy’s project webpage (click here for webpage: https://www.natureaustralia.org.au/what-we-do/our-priorities/oceans/ocean-stories/victorias-oyster-reefs/) and or contact them at australia@tnc.org.