NEARLY 20,000 native oysters are being reintroduced to Dún Laoghaire Harbour as part of a major restoration effort aimed at reviving the species in Dublin Bay after a 200-year absence.
The project is being led by the Green Ocean Foundation and is aiming not only to restore oyster populations but also to improve water quality.
The oysters, harvested from the waters off County Kerry, have been placed in specially designed floating baskets along the harbour’s middle pier by a team of 20 volunteers.
According to the Foundation’s director, David Lawlor, oysters act as “climate heroes”.
Each adult can filter up to 200 litres of seawater a day.
This filtration helps sunlight reach the seabed, helping the growth of seagrass and seaweed.
Over the past two years, the Green Ocean Foundation has piloted similar “oyster garden” installations across Dublin Bay, including at Howth, Malahide and Poolbeg.
The initiative has expanded with the cooperation of six different yacht clubs, including the Royal St George and the National Yacht Clubs in Dún Laoghaire.
These clubs now host baskets containing 10 to 15 adult oysters each, suspended from marina pontoons one metre below the surface.
Early results have been encouraging.
The DCU Water Institute, which is monitoring the scheme, has reported strong oyster survival and reproduction rates.
In 2024, spat (juvenile oysters) were observed settling in the area, proving that the oysters are beginning to reproduce naturally.
Mortality rates have remained below 3%, and students from University College Dublin and Trinity College Dublin continue to study oyster health and biodiversity impacts.
The long-term goal is to establish a self-sustaining broodstock in Dublin Bay that could evolve into thriving reef systems over the next 15 to 20 years.
These reefs will help stabilise the seabed and provide natural buffers against storm surges.
Lawlor emphasised that the project relies on community involvement rather than commercial motives or government funding.
“Real climate action starts at the local level,” he told RTÉ.
“Community-driven projects like this can restore ecosystems while inspiring wider participation from schools, clubs, and businesses.”
If successful, the initiative will expand further along Ireland’s east coast, with potential new locations such as Greystones in County Wicklow already being considered.
See More: Dublin Bay, Dun Laoghaire, Oyster Farm
