Algal bloom in west kills lugworms

A MASS mortality of lugworms and shellfish on the west coast has been caused by a seasonal algal bloom, the Marine Institute said.

Thousands of lugworms have died on the north Mayo coastline since last weekend, while dead cockles have been found on the sand at Rossport, Glengad and Broadhaven Bay.

Marine Institute scientist Joe Silke, who runs the national phytoplankton monitoring programme, said the deaths were caused by an algal bloom or “red tide” which was toxic to bottom-dwelling marine species, such as shellfish and certain species of fish.

The bloom has been identified as a type of Karenia red tide, which can also affect seabirds and other species including dolphins. However, the bloom was “naturally occurring”, formed by phytoplankton or microscopic plants, and posed no risk to human health, Mr Silke said.

Evidence of the bloom has been identified from Donegal to the Clare coastline, he said. A previous bloom or red tide on this part of the coastline lasted throughout the summer of 2005, but it was “very difficult to predict” how long this bloom would last.