Fish-killing algal bloom subsides


THE ALGAL bloom which has killed fish, shellfish and other marine life off the west coast over the past month has begun to “subside”, according to the Marine Institute.

However, the Food Safety Authority of Ireland has warned of the dangers of gathering and eating wild shellfish, following reports that a dozen people have had suspected food poisoning in recent weeks.

The FSAI said it “suspects” the food poisoning cases are linked to the naturally occurring algal bloom. Over 10 cases were reported in Galway, Mayo and Sligo in recent weeks, it says.

The bloom, Karenia mikimotoi, was concentrated on the coastline from Mayo to Donegal, and in areas further down the west coast.

Marine Institute scientist Joe Silke said that the most recent satellite imagery and seawater samples show a “significant decrease in the concentration”.

The bloom, common in all European waters, was similar in impact and duration to one off the Irish coast in 2005, he said, and was probably due to a combination of environmental conditions and ocean currents.

While not directly harmful to swimmers it can have an indirect impact when eating shellfish in affected areas.

Oyster farms reported losses of between 20 per cent to 80 per cent in some sites and farms with juvenile oysters reported significant deaths, Mr Silke said. Lobster and prawn fishermen and sea anglers also reported low catches, particularly in the Donegal area.