Algae at Portstewart Strand (27.10.2025). Photo credit: National Trust
Visitors to Portstewart Strand are being urged to stay out of the water after blue-green algae was spotted along the beach following strong winds over the weekend.
The Department of Agriculture, Environment and Rural Affairs (DAERA) has confirmed that several algal scums have appeared and are currently being tested.
As a precaution, an ‘Advice Against Bathing’ notice has been issued from today (Monday, 27 October).
Officials have warned that the algae could pose a risk to public health, and visitors are advised not to swim, wade, fish, boat or kayak until further notice.
Dog owners are also being asked to take extra care, as blue-green algae can be particularly harmful to animals.
All pets should be kept on leads during what DAERA has called a ‘Red Alert’ under the Inter-Agency Blue-Green Algae Protocol.
Monitoring of the beach is ongoing, and DAERA have said an update will be issued to the public when test results are available.
Algae at Portstewart Strand (27.10.2025). Photo credit: National Trust
Blue-green algae returned to Lough Neagh for the third summer in a row
Anyone who suspects they have seen blue-green algae is encouraged to report it using the Northern Ireland Environment Agency’s reporting app.
The discovery of blue-green algae at Portstewart Strand coincides with ongoing concerns over algae blooms in Lough Neagh – the UK’s largest freshwater lake.
Algal growth has appeared in the lough intermittently for more than 60 years, but the last three summers have seen the largest outbreaks since the 1970s.
Factors such as fertilizer runoff, climate change, and invasive species like zebra mussels are contributing to the problem. The blooms have led to fish kills and pose risks to wildlife and human health.