Northern Ireland’s first floating oyster reef launched at Glenarm in major boost for marine wildlife

Northern Ireland's first floating oyster reef has been launched at Glenarm Marina in partnership with Mid and East Antrim Borough Council. The innovative floating reef provides a sheltered home for more than 10,000 young native European oysters, helping to restore a lost marine habitat and support healthier seas. (All images and video © Ulster Wildlife)

Northern Ireland’s first floating oyster reef has been launched at Glenarm Marina, creating a new home for thousands of native oysters and marking a significant step in efforts to restore one of the country’s most endangered marine habitats.

The pioneering project, unveiled by Ulster Wildlife to coincide with World Oyster Day on Wednesday, 5 August, is designed to help revive the near-extinct native European flat oyster while improving biodiversity and the health of Northern Ireland’s coastal waters.

The custom-built floating reef currently supports around 10,000 juvenile European oysters – known as spat – attached to scallop shells, alongside approximately 200 adult oysters growing in biodegradable bags.

By recreating the structure of a natural oyster reef above the seabed, conservationists hope the project will demonstrate a new way of restoring oyster populations on a much larger scale.

A habitat lost for generations

Thousands of young native European oysters are growing on scallop shells beneath the floating reef at Glenarm Marina established by Ulster Wildlife.

Native oyster reefs were once widespread around Northern Ireland’s coastline but have suffered dramatic declines through overharvesting, habitat destruction, pollution and disease.

Their loss has had consequences far beyond the oysters themselves. European oysters naturally filter seawater, improve water quality and create complex reef habitats that provide shelter and food for a wide range of marine life.

The Glenarm project builds on Ulster Wildlife’s existing oyster nursery at the marina and follows another landmark achievement earlier this year, when the charity successfully deployed native oysters onto the seabed in Belfast Lough for the first time.

Early results from the floating reef have been encouraging, with oyster survival rates exceeding 80 per cent.

Artificial intelligence helping monitor marine life

Views from the Eco Detect underwater camera

To understand how wildlife is using the new habitat, an Eco-Detect underwater camera system powered by machine learning has been installed alongside the floating reef.

Operating day and night, the technology has already recorded more than 7,000 wildlife detections during its first three months, capturing species including gobies and black guillemots visiting the structure.

The monitoring complements existing research into the smaller creatures that naturally colonise oyster reefs, helping conservationists build a fuller picture of the biodiversity these habitats support.

Dr Nick Baker Horne, Marine Conservation Manager at Ulster Wildlife, beside Northern Ireland's first floating oyster reef at Glenarm Marina.

Dr Nick Baker Horne, Marine Conservation Manager at Ulster Wildlife, said:

“The floating oyster reef represents an exciting new chapter in our work to restore the native European oyster to Northern Ireland’s seas and revive a habitat that has been lost for generations. This project allows us to showcase the incredible habitat created by native oysters while continuing to build our oyster restoration efforts and deepen our understanding of the wildlife these reefs can support.

“Thanks to Eco-Detect’s camera system, we can now see what species are interacting with this floating reef, day and night.

Guillemot swimming below the pontoon filmed on the Eco Detect underwater camera

“Oyster reefs are true ecosystem engineers – they help improve water quality, support richer marine biodiversity and create healthier coastal ecosystems. Clearer waters and thriving marine life can benefit local fisheries, while living reefs also store carbon and help protect coastlines from storm surges.

“Restoring these vital habitats is essential if we want to build healthier, more resilient seas for the future.”

Benefits beyond oysters

The project could also support wider marine restoration work in Glenarm.

Ulster Wildlife plans to use the floating reef to collect naturally washed-up seagrass before growing and replanting it into the nearby seagrass meadow, helping strengthen another valuable but fragile underwater habitat.

The initiative has been developed in partnership with Mid and East Antrim Borough Council and funded by the Department of Agriculture, Environment and Rural Affairs (DAERA) through the Carrier Bag Levy. It forms part of a broader programme to restore native oysters and other important blue carbon habitats across Northern Ireland.

Why native oysters matter

Dr Nick Baker Horne, Marine Conservation Manager at Ulster Wildlife, inspects Northern Ireland's first floating oyster reef at Glenarm Marina.

Native European oysters (Ostrea edulis) are now considered one of the world’s most threatened marine habitats. Scientists estimate oyster populations across Europe have declined by around 95 per cent since the 19th century.

Ulster Wildlife currently manages four native oyster nurseries at Bangor Marina, Belfast Harbour, Carrickfergus and Glenarm, all aimed at restoring the species to Northern Ireland’s seas.

Unlike the Pacific oysters commonly sold for food in the UK and Ireland, these native oysters are not for human consumption. Instead, they are being carefully bred and protected to rebuild self-sustaining reefs that can support marine wildlife for generations to come.

More information about the project is available at www.ulsterwildlife.org/native-oysters.