Turning the tide for marine ecology

In a world swamped by news of environmental disaster and ecological decline, it is exhilarating to celebrate a remarkable achievement in marine restoration and recovery.

A rapid decline in fish stocks along the South Australian coastline demonstrated a need for action on restoring marine habitats.

Our researchers looked into the history of this coastal settlement, what had caused the decline over decades and what could be done to reverse it.

Thousands of hectares of native oyster reefs once girdled these shallow bays of south-eastern Australia.

A century of over-harvesting and dredging for raw materials saw the oyster population crash, the ecosystem destroyed and the coastline severely degraded.

One ingenious solution was to build a huge artificial shellfish reef off the coast of Ardrossan, in South Australia’s Gulf St Vincent, to try to restore a natural balance.

Oysters in large groups provide habitat for many sea creatures and a natural filtration system for the marine environment.

They take excess nutrients from the water and deposit them as a kind of organic fertiliser for seagrass beds.

Strong and healthy seagrass calms wave action, reducing the impact of storm surges and coastal erosion.

The whole ecosystem supplies food and shelter for many kinds of fish, which in turn provide food and recreation for local people.

Collaborating with the State Government, the local council and the Nature Conservancy, the research team instigated one of the world’s largest marine restoration projects.

Around 18,000 tonnes of limestone and seven million baby oysters form the foundation of a shellfish reef stretching almost two kilometres along the coast.

Funded by the Ian Potter Foundation and the Federal Government, the almost $7 million, two-year investment has provided a model for future projects at home and abroad. Our researchers continue to monitor the health of the reef and the success of the restoration, which has made a real difference to the local ecology, economy and community.