Restoring oyster reefs

By Ashleigh Fielding | posted on November 28, 2019

AN OYSTER reef that once supplied early Australians with food and contributed to the foundations of the Albany townsite will be reconstructed in the name of conservation.

The reef construction project began last week with the transportation of 1000 tonnes of limestone from the City of Albany Quarry to Emu Point Boat Harbour, destined for selected sites of Oyster Harbour to cover an area of more than 800sqm.

The State Government contributed $1 million to the effort to aid the restoration of Australian flat oyster habitat.

The Nature Conservancy’s Marine Project Coordinator Alex Hams said Oyster Harbour had been overharvested in the 1800s and now needed to be rehabilitated and protected.

“It was overfished during the early settlement period of Albany, around the 1830s to the late 1800s, as it was a really readily available source of protein – Australian flat oyster was very similar to European oyster, which the settlers were used to,” he explained.

“They also used to dredge out the shell and place it in lime kilns, to create cement for the construction of the old buildings in Albany.”

Mr Hams said the issue had not been addressed prior to now as it was not previously known just how much of an impact oyster reefs had on the environment.

“Because it was lost so long ago, we didn’t realise how important it was for the ecosystem and the benefits of it,” he said.

“A big benefit we know from previous examples is that oyster reefs attract other species, because they provide a structure for plant growth and shelter, and oysters are consumed by some fish and crab species.”

He said the ultimate aim was to establish multiple large-scale reefs to replicate what was once in Oyster Harbour, maintain a sustainable population of Australian flat oyster and promote conservation.

“Rebuilding these locally extinct reefs will bring back so many benefits to the harbour and the Albany community including improved water quality, greater marine biodiversity and boosted fish populations,” Mr Hams said.

“As an Albany local myself, I can’t wait to see the difference this will make.”

A barge has been used over the past few days to move the limestone from Emu Point Boat Harbour to the reef building sites, where it will then be deployed into the water by an onboard excavator.

Upon completion, the new reefs will be seeded with more than one million Australian flat oys- ters, currently growing at Albany Shellfish Hatchery.

Mr Hams said potentially only five to 10 per cent of the seeded oysters would survive to reach maturity, and this maturation process would take approximately two to five years.

He said the oysters would not be grown for the trade market and fishers would be discouraged from collecting them.

“We are doing this for conservation purposes,” he reiterated. Albany MLA Peter Watson said Albany was a major step closer to restoring the flat oyster habitat.

“Our local and visiting fishers continue to enjoy the diversity of fish species living within the harbour and the new reefs will further enhance this experience,” he added.