Lettuce sea what we can do

The strategic use of oysters and mussels may be the key to solving Cork’s increasing sea lettuce problem.

Cork County Councillor Audrey Buckley (FF), who lives in Crosshaven, has called for immediate action on the issue which she said is driven by excess nutrient inputs, particularly nitrates in the water.

In a motion put forward at Monday’s full meeting of Cork County Council, Cllr Buckley asked that the issue be brought to the attention of the Marine Institute and the Local Authorities Water Programme (LAWPRO).

The Carrigaline MD representative said she has received many complaints from locals and visitors regarding sea lettuce washing up on the coast, making beaches inaccessible while attracting flies and creating “noxious fumes”.

She said: “Sea lettuce is overgrown in especially polluted waters. So, it kills everything that's underneath. Nothing can grow.

“This is an issue that is not going away. If anything, it appears to be getting worse year on year.

“At present, our response is largely reactive, bringing in machinery to remove the sea lettuce from our beaches when funding allows.

“That work is necessary but is not sustainable and it does not address the root cause of the problem.”

In her research, Cllr Buckley found other communities tackling similar problems, including a number of projects in Wales in the UK where shellfish systems using the likes of mussels and oysters are being trialled as a solution.

“Oysters are often described as the kidneys of the sea,” continued Cllr Buckley.

“They naturally filter seawater, removing excess nitrates, plankton, and alginates. Cleaner water improves visibility, allows sunlight to reach the seabed, which helps support the growth of seagrass,” she said.

Supporting the motion was Fianna Fáil councillor Dominic Finn who said sea lettuce is also a problem in Cobh.

He said: “We have some popular little beaches in Cobh where an awful lot of the community come, even coming from Carrigtwohill to go swimming in these areas.”

Social Democrats Councillor Isobel Towse also supported the motion and suggested that illegal slurry spreading may be to blame.

She said: “We mustn't lose sight of the root cause of these blooms, which is excess nutrients and how they entered the water.

“The vast, vast majority of farmers are following the rules, but it only takes one farmer to breach the rules a few times and you've got a visible problem.

“We need better enforcement around illegal slurry spreading and we need to reinstate ditches and hedges so that nutrients don't just wash off the land,” she concluded.