Victoria's lost reefs rediscovered

Getting shellfish reefs back into Port Phillip Bay.

Our reefs are in danger, but which ones are the most threatened?  The Great Barrier Reef off the Queensland coast? Or maybe Ningaloo Reef off WA’s Coral Coast?  While the community’s attention is often understandably focused on threats to the Great Barrier Reef for example, it’s shellfish reefs that have suffered the most. Since European settlement, we’ve lost almost all of these reefs from southern Australia. At The Nature Conservancy, we’re determined to do something to reverse this decline.

Situated on the doorstep of Melbourne, Port Phillip Bay contains a wide range of habitats like seagrasses, hard corals and sandy plains. A hundred years ago it was also home to extensive oyster reefs and mussel beds that supported a range of sea life such as crabs, sea squirts, snails and sponges. Sadly, after many years of commercial dredging, pollution, introduced species and disease, these shellfish reefs have virtually disappeared.

We’ve joined forces with Fisheries Victoria, The Thomas Foundation, the Victorian Recreational Fishing Licence Trust Fund, and the Albert Park Yachting and Angling Club to rebuild the Bay’s shellfish reefs. With experience gained from our reef restoration projects around the world, we’ve tested a range of cutting edge methods for re-establishing the reefs, bringing all the benefits of oysters back into the Bay.

The first two reefs to be restored are at Geelong Arm (Wilson Spit Reef) and Hobsons Bay (Margaret’s Reef). We started by growing native flat oysters at the Victorian Shellfish Hatchery in Queenscliff. Next we laid down limestone rock foundations at the sites, providing a bed upon which divers then placed the young oysters from the hatchery. Here they can settle and continue to grow, establishing themselves in their new home. We’re also laying mussels nearby to trial mussel bed restoration.

The results so far have shown a high oyster survival rate (more than 50% on average), which surpasses trial expectations globally. The next stage will see us scale up from a patchwork of one square metre plots to 1,600 square metres over the two sites, planned for the summer of 2016/17.

Beyond this we are formulating long-term plans to implement a large-scale restoration program in Port Phillip Bay with the aim of creating self-sustaining shellfish reefs, boosting fish populations and providing cleaner water for nature and people to enjoy.

ABC TV News story on shellfish reef restoration project
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