Lost and Found
The Return of Australia’s Forgotten Oyster Reefs
The Native Oyster Reefs You Never Knew Existed
Coffin Bay is renowned for its world-class oysters, but few realise that long before aquaculture took hold, the region was home to vast native oyster reefs.
The flat oyster (Ostrea angasi) formed extensive reef structures that supported marine life, stabilised the seafloor, and filtered coastal waters across thousands of kilometers of coastline, and Coffin Bay had some of the biggest reefs.
A Reef Rediscovered
Oyster reefs are far more than clusters of shellfish. Acting as natural water filters, they can significantly improve water clarity and quality by removing excess nutrients. A single oyster can filter up to 100 litres of water per day, helping to maintain a balanced marine environment. These reefs also serve as vital habitats, providing shelter and food for a diverse array of marine species, from small fish and crabs to larger predators like rays and sharks.
However, their disappearance has had profound consequences. Without oyster reefs, sedimentation increases, fish populations decline, and coastal erosion accelerates. Recognising these challenges, marine restoration groups, scientists, and traditional custodians are collaborating to re-establish these lost ecosystems.
A Movement for Restoration
The discovery in Coffin Bay has provided a crucial missing link in the push to restore Australia’s native oyster reefs. Dr. Dominic McAfee, a marine restoration scientist from the University of Adelaide, has been at the forefront of research into these lost ecosystems.
“Finding this reef was a real breakthrough,” Dr. McAfee explains. “It proves that remnants of native oyster reefs still exist, and it gives us a blueprint for restoration.”
His team, working closely with local fishers, divers, school students and restoration groups, is using insights from these surviving reefs to guide large-scale recovery efforts. Across South Australia, large-scale restoration efforts led by the South Australian Government and The Nature Conservancy, have laid down limestone and recycled shells to provide a foundation for new oyster growth. Slowly but surely, the reefs are returning.
A Community Effort
Now Dr McAfee and Mr Katz are helping communities to drive their own native oyster restoration efforts, with the Coffin Bay community playing a key role. Passionate residents, oyster farmers, volunteers, and conservation group EYRE Lab have come together to build new reefs using recycled oyster shell and the latest restoration science to encourage native oyster larvae to settle.
With new experimental reefs already constructed at five sites, the project is demonstrating the power of community-driven conservation. And the efforts are beginning to pay off—divers and researchers are now seeing young oysters taking hold, a promising sign that these ecosystems can be revived.
In a major step forward, flat oyster ecosystems are currently being considered for national conservation protection as a threatened ecological community. If recognised, this could further bolster funding and long-term restoration efforts.
The Ripple Effect
Beyond their ecological benefits, oyster reefs offer economic and cultural value. Revitalising these habitats can support sustainable fisheries, boost ecotourism, and strengthen community connections to marine conservation, and revive cultural connections that have persisted for thousands of years. Indigenous knowledge has a key role to play in the success of these efforts, and the Nauo community are excited to see these efforts to repair their Sea Country.
Restoring oyster reefs is about more than rebuilding what was lost—it’s about ensuring a thriving future for Australia’s marine environments. As Dr. McAfee puts it, “It’s about recognising the role these reefs played in the past and working to make sure they can support life again.”
Key Supporters
This vital restoration work has been made possible through the support of key organisations, including the Environment Institute at the University of Adelaide and the Department for Environment and Water, South Australian Government. Their commitment to marine conservation is helping to rebuild these critical habitats and safeguard them for future generations.
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Restoration
Australian researchers are working at the global forefront of marine habitat restoration, with projects underway in every state along the Great Southern Reef. Habitat restoration is a resource intensive exercise used as a last resort for areas where vital habitats have been lost or are in decline and natural recovery is not occurring. Our restoration page showcases some of the active restoration projects on the GSR working to restore seaweeds, seagrasses, and oyster reefs.
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People
Get inspired by the people who live and breathe the Great Southern Reef. We celebrate the passionate stewards — from abalone farmers pioneering sustainable practices to artists drawing inspiration from the underwater realms and indigenous custodians sharing age-old stories and wisdom. Here, we bring you closer to the people who, with their unique perspectives and endeavours, contribute to the rich and diverse narrative of the Great Southern Reef.
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FAQ's
Want to learn more about the Great Southern Reef? Our FAQ page covers everything from its rich biodiversity and ecological importance to the challenges it faces and how you can get involved. Explore the answers to common questions and discover why this incredible ecosystem needs our attention
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Values
The Great Southern Reef provides a myriad of benefits to humans. All these benefits have value and will hold importance for people, for a variety of reasons. An artist might value the reef for the awe and wonder it provides that inspires their creativity whereas a traditional owner might value the reef for the connection to cultural practices that have been passed on for thousands of generations. Our values page explores how the GSR enriches our lives, and how scientists are working towards quantifying this value.
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Marine Life
The Great Southern Reef is a global biodiversity hotspot with many species found no where else on the planet. From cuttlefish to crabs and seadragons to starfish, in our marine life page you will learn about some of the iconic marine species that live in Australia’s kelp forests.
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Places
Venture into the untouched corners of the Great Southern Reef, where pristine landscapes meet remote havens of biodiversity. Our places page guides you through a curated taste of the GSR’s iconic places, each offering a unique glimpse into the diverse ecosystems that flourish both above and below the water.
