The first confirmed report of blue-green algae in 2025 was received by the Northern Ireland Environment Agency (NIEA) on April 2, for Martray Lough, Ballygawley, Co. Tyrone.
A report was received by the NIEA on April 9, regarding Ballysaggart Lough (Black Lough) in Dungannon, Co. Tyrone.
In addition, two reports have been made to NIEA from locations on Lough Neagh and were verified on April 10 and 11, at Traad Point, Co. Derry, and Kinturk (Curran’s Quay), Co. Tyrone.
The NIEA said it is aware of potential sightings being circulated on social media and would encourage the public to report theses via the Bloomin’ Algae app.
A spokesperson for the Department of Agriculture, Environment and Rural Affairs (DAERA) said: “Minister Muir is on record a number of times saying that there are no quick fixes, with problems decades in the making and decades in the fixing.
“It is therefore, unfortunately, no surprise that we are beginning to see algae-blooms re-appear again this year, particularly with the good weather.
“The severity and scale of the problem we will be facing this summer will be dependent on a number of factors. Work is well underway to tackle the problem through the Lough Neagh Action Plan and the minister is determined to turn the tide on water quality, but we know that this will be a long-term endeavour.”
Algae
Blue-green algae is not actually an alga but rather a type of bacteria called cyanobacteria. Cyanobacteria naturally inhabit freshwater, coastal and marine waters and, like plants, require sunlight, nutrients and carbon dioxide to grow and reproduce.
Cyanobacteria can increase greatly in numbers and form visible ‘blooms’, which can lead to poor water quality and the production of harmful toxins.
Some blooms can produce toxins that can potentially be harmful to animal and public health. It is not possible to tell if a bloom is producing toxins without additional testing; however, caution is advised where blooms have been confirmed.
Minister Muir addressed the issue at a meetng of the Agricultural, Environment and Rural Affairs (AERA) committee last Thursday (April 10).
He said: “Spring should be about renewal not news reports of blue-green algae. Significant work is already underway to tackle the nutrient overload in our rivers, lakes and loughs.
“I will continue to lead and seek support for the tough decisions needed over the time ahead to improve our waterways and tackle climate change,” he added.
