Restoring large oyster reefs may be able to turn the tide on South Australia’s toxic algal bloom, some conservation scientists say.
Scientists from The Nature Conservancy (TNC) Australia say shellfish reefs could even help prevent future marine disasters.
Dr Michaela Dommisse, who is TNC Australia’s Director of Oceans, says the current SA bloom is an unprecedented natural disaster that is likely to become more frequent.
“Communities are hurting and demanding answers. We have one: reef restoration. It’s proven, it’s working, and it starts with the humble oyster, the water filters or kidneys of the sea.”
The comment follows the recent release of a $102.5 million algal bloom summer plan for the state. Click here for our story on the plan.
The plan allocated $20.6m to natural solutions with around half for large-scale shellfish reef restoration which The Nature Conservancy and other organisations will help deliver.
“While this is an essential first step, to rebuild these natural filtration systems at the scale needed to address this crisis – and mitigate future disasters – far greater investment is required,” Dr Dommisse says.
OYSTER, MUSSEL PROTECTION
Australia once hosted vast shellfish reef ecosystems, primarily built by native oysters and mussels, on the southern coastline for tens of thousands of years.
But over the last century, 99% of these ecosystems were destroyed by dredging and overharvest, the conservancy says.
“Large-scale shellfish reef restoration is essential infrastructure,” Dr Dommisse says.
“We must scale up national and state restoration programs, starting in South Australia.
“Community volunteer efforts are valuable but only large-scale action with investment … will deliver fast results, better value and impact, and regional economic uplift.”
TNC says it has led global shellfish reef restoration efforts for more than 30 years, and since 2018, has worked with others, including traditional custodians, to rebuild reefs across Australia.
It restored four reefs in the affected area of South Australia (Windara and Glenelg reefs, Nepean Bay and O’Sullivan Beach Reef) and says evidence shows oysters on these reefs feeding on the toxic algae.
“Investing proportionately to the scale of loss is crucial. Rebuilding this network of reefs across Australia’s southern coastline will require at least $500m over five to 10 years,” Dr Dommisse says.
“This is infrastructure that creates jobs, protects fisheries, and safeguards an economy worth $120 billion annually.
“It is a fraction of what we invest in other infrastructure,” Dr Dommisse says.
The TNC points to the cost of major infrastructure projects in comparison: Sydney’s $58.3 billion Metro Tunnel, $13.4 bn for Melbourne’s equivalent, $8bn for Brisbane’s Cross River Rail and $15.4bn for Adelaide’s South Road upgrade ($1.4m per metre of road).
“Now is the time to commit to large-scale habitat restoration and give our ocean the kidney transplant it so urgently needs.
“Governments must lead with significant and immediate upfront investment so others can follow,” Dr Dommisse said.
The TNC is also running a petition that can be signed at www.natureaustralia.org/beatthebloom
