Shellfish reefs could restore health of Peel Harvey Estuary

Murdoch University researcher Alan Cottingham conducting in-water trials.
Murdoch University researcher Alan Cottingham conducting in-water trials.

RESEARCHERS from The Nature Conservancy and Murdoch University are using new micro-tech devices to assess the viability of creating new shellfish reefs in the Peel-Harvey Estuary.

TNC Australia marine manager Chris Gillies is leading the work.

“Shellfish reefs are highly effective at restoring the health of our stressed bays and estuaries,” Dr Gillies said.

“They create habitat for a range of other aquatic species, boost local fish and swimmer crab stocks, protect shorelines from erosion and improve water quality due to their natural filtration power.”

The research involves a collaboration with the local Marine Men’s Shed members who are helping to deploy native Blue Mussels in cages throughout the estuary.

At each location mussels will be fitted with a purpose-built ‘valvometer’ – a tiny device attached to each individual mussel to record when it’s open and feeding, and when it’s closed.

Murdoch University researcher Alan Cottingham said the data from the valvometers will be used to assess the health of the mussels over time.

They will then link this information to changes in water quality to determine where in the estuary it will be best to build new reefs.

The field research will be complemented by further laboratory studies and risk assessments to assess exactly which native shellfish species have the best chance of long-term survival and reef creation in the estuary.

Once abundant throughout the bays and estuaries of southern Australia from Perth to Sydney, 99 per cent of Australian Flat Oyster reefs have been wiped out since European settlement through over exploitation.

TNC is working to correct this situation with successful projects already underway to restore lost shellfish reefs, and all the benefits they bring.

The work in the Peel-Harvey Estuary has been made possible through the support of the Alcoa Foundation, which has provided US$500,000 for TNC to combine its international expertise with local knowledge to investigate ways of improving and protecting the internationally recognised waterway.

Alcoa of Australia chairperson Michael Parker said by working together the ongoing health of waterways like the Peel-Harvey Estuary could be ensured.

“The estuary is the lifeblood of our communities not only from an environmental perspective but also socially and economically,” he said.