Native oysters have made a return to Carrickfergus as part of efforts to restore Belfast Lough’s small but endangered population.
Over 900 mature oysters (Ostrea edulis) have been suspended in 30 purpose-built cages over the edges of Carrickfergus Marina’s pontoons to help revive the species.
Led by conservation charity Ulster Wildlife in partnership with Mid and East Antrim Borough Council, the initiative could see up to 900 million oyster larvae released into surrounding waters every year.
One oyster can release up to a million larvae per year. They can also change sex, so there is always the correct ratio of males to females. By housing oysters close together in cages, it encourages them to spawn.
Carrickfergus was the heart of Belfast Lough’s thriving native oyster industry in the 1850s. However, overfishing and disease led to their disappearance.
Many of the oysters on sale and eaten in the UK and Ireland today are Pacific oysters – an invasive species brought here from Japan in the 1970s following the demise of the native oyster.
There are many benefits to reintroducing oysters into the area. In addition to supporting the expansion of wild populations, the oysters will help boost biodiversity and improve water quality by filtering pollutants.
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Existing oyster reefs have been proven to protect considerable stores of carbon, which can avoid further releases of carbon into the atmosphere.
Funded by Daera, this new nursery forms part of a network of native oyster nurseries in Belfast Lough, including Bangor Marina, Belfast Harbour, and Glenarm.
Dr Nick Baker-Horne, marine conservation manager at Ulster Wildlife, said: “This is a significant step forward in helping to restore one of our most valuable native species. A growing native oyster population will have far-reaching benefits for the wider marine environment.
“These small but mighty creatures create vital habitat for juvenile fish as their larvae settle on the seabed and dramatically improve water quality. One oyster can filter a bathtub of water per day.
Karena Catterson, harbour and marinas manager at Mid and East Antrim Borough Council, added: “We are thrilled to be playing our part in restoring this endangered native species.
“Not only will this initiative help to restore a species once abundant in these waters, but it will also improve water clarity, boost biodiversity, and celebrate Carrickfergus’ rich maritime heritage.
“I look forward to seeing the project grow and flourish in the years ahead.”
The oysters, sourced from Loch Ryan in Scotland, underwent rigorous screening for disease and cleaning before being introduced to their new home at Carrickfergus Marina.
Ulster Wildlife is appealing for volunteers to help monitor the oysters as they settle into their new home. This involves conducting regular health checks to assess growth rates and surveying wildlife around the cages.
Training days will take place on April 16 and 23. Those interested can visit www.ulsterwildlife.org/volunteer or email [email protected] to find out more.