SYDNEY: Researchers from the University of Adelaide have discovered the loss of naturally occurring oyster reefs that spanned South Australia’s coastline 70 years ago.
PhD student Heidi Alleway and her supervisor Professor Sean Connell have put together a historical reconstruction of the reefs, which were formed by the native flat oyster, also known as the angasi.
Ms Alleway said they have found that, historically, reefs were very widely distributed and could have spanned across more than 1,500 kilometres of the South Australian coastline, today the reefs are gone.
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AUDIO: University of Adelaide PhD student Heidi Alleway talks about the discovery they have made about the loss of oyster reefs in South Australia (ABC Rural)
“We do not actually have any oyster reefs that we are aware of, that naturally occur in the marine environment,” she said.
“Those reefs have been lost due to a commercial dredge fishery, which operated during the 1800s into the early 1900s and that fishery over exploited the native oyster and the oyster reefs.”
Ms Alleway said the use of dredging equipment to collect the native oysters could have caused the damage to the reefs.
“It was a bit like a metal rake I guess and it had a metal bag attached to the end and they would actually drag that dredge over the oyster reef and that really broke up the habitat.”
She said the research has been done now because the state almost has a “collective amnesia”, where some of the history is forgotten over time.
“This is the interesting thing with fisheries and activities that actually happen over a century ago, as time passes and as we don’t sort of have that information carried forward, we do have a tendency to forget,” she said.
