Algae in Castlewellan Lake

Algae in Castlewellan Lake

4 September 2024

WARNINGS have been issued to members of the public as blue-green algae has been found in Castlewellan Lake. 

Newry, Mourne and Down Council hx advised visitors to observe and abide by any warning notices positioned around the lake. 

The council has told the public not to enter or swim in the water, refrain from recreational water sports and to not drink it. 

Visitors are also advised to exercise caution while walking their dogs as ingestion of the toxin has been fatal for animals. 

The council has also warned keen fishers to not eat fish that has been caught from the water as it can cause severe illness and possibly death. 

Blue-green algae is a type of bacteria called cyanobacteria, which naturally inhabits freshwater, coastal water and marine waters.

The bacteria can increase greatly in numbers and form visible ‘blooms’ which can lead to poor water quality and the production of harmful toxins.

The lake, which is managed by the council, has had previous issues with blue-green algae. 

In 2020, the lake was closed to the public twice after the appearance of algae which breaches water quality safety standards.

South Down MLA, Colin McGrath said: “It’s sad to hear that algae has been reported at Castlewellan Lake.

“I hope that the council and other authorities do all they can to treat and manage the issue.

“I’m disappointed that given the prevalence of it in Lough Neagh from last year that DAERA couldn’t have been better prepared to prevent it spreading.”

Mr McGrath added: “It is just another item on a very long list that our Executive seems quite incapable of managing.” 

A spokesperson for Newry, Mourne and Down Council said: “The council will continue to monitor Castlewellan Lake and keep members of the public updated on public health guidelines.”

A spokesperson for DAERA said reports of blue green algae at the lake were submitted via Bloomin Algae App on Sunday and was confirmed by the Department on Monday.

The spokesperson added that it was “clear that significant action needs to be taken to address poor water quality in Northern Ireland”.