Bivalves have been an important source of food and shelter in coastal settlements since precolonial times. In Port Lincoln, SA, home to delicious. Harvey Norman Produce Awards medallist Kinkawooka Mussels, there is evidence of mussel and oyster middens dating back 6000 years.

In the early days of white settlement, large ships had to navigate Sydney Harbour’s vast oyster reefs, which acted as marine kidneys, filtering pollution. Today, researchers estimate that almost all natural shellfish reefs in NSW have been wiped out. The good news is that the best thing you can do is hightail it to oyster happy hour.

OceanWatch Australia’s Living Shorelines initiative is transforming the 3000 tonnes of oyster shell waste generated by the NSW hospitality industry each year to rebuild reefs, bagging shells in coconut fibre to strategically peg to eroded shorelines.

Similarly, the Sydney Institute of Marine Science, a collaboration between four NSW universities, has a five-year project to restore Sydney Harbour’s historic reefs and the once prolific native angasi flat oyster.

In the US, New York City’s Billion Oyster Project launched in 2014 to clean up the city’s harbour in the same manner. Returning the shells to the waterway, the project aims to restore mollusc colonies with one billion oysters across 40 hectares of new reef by 2035.

A single oyster can filter up to 200 litres of water a day in a process known as benign farming, because they pull nutrients from the water without needing added feed. In a world where so much of what we consume has a negative environmental footprint, the mighty mollusc could be one of the most sustainable choices.