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'No surprise' that blue-green algae back in Lough Neagh

BBC A man with grey hair, beard and moustache smiles at he camera as he wears silver metal glasses, a red coat and a black spotted shirt.BBC
Gerry Darby from Lough Neagh partnership says he is "not surprised" by the return of the blue-green algae

Blue-green algae has been detected in Lough Neagh for the first time in 2025, the Northern Ireland Environment Agency (NIEA) has confirmed.

The lough, the UK's largest freshwater lake, has been blighted by large blooms of the potentially toxic blue-green algae in recent years.

In a statement, the NIEA said reports of blue-green algae at Lough Neagh were verified on 10 and 11 April at both Traad Point and Kinturk (Curran's Quay).

Exposure to high levels of any blue-green algae blooms - whether by contact with water blooms, swallowing that water or inhaling airborne droplets - can cause health effects in people and animals.

What is blue-green algae?

A sign on a wooden post. The sign has a yellow banner which reads: Caution Blue-Green Algae in large black font.
Reports of blue-green algae at Lough Neagh were confirmed at both Traad Point and Kinturk (Curran's Quay)

Blue-green algae, technically known as cyanobacteria, is a collection of microscopic organisms that are naturally present in lakes and streams.

Under certain conditions, blue-green algae can become abundant in warm, shallow, undisturbed, nutrient-rich surface waters that receive a lot of sunlight.

When this occurs, blue-green algae can form blooms that discolour the water, or produce floating mats or scums on the water's surface.

The algae are bacteria, which can cause skin irritation and sickness in people who come into contact with it, but the biggest risk is to pets, livestock and wildlife.

Why is it back?

A body of water with a green substance over the top of it. There are trees and bushes surrounding the water. There is a blue water bottle lying in the water along with brown branches.
Blue-green algae has been spotted at Kinturk

Speaking to BBC News NI, Gerry Darby from Lough Neagh partnership said he is not surprised by the presence of blue-green algae in the lough.

"Over the last two years the science has been saying that it will take a long time to resolve the problem of blue-green algae in the lough," he stated.

"Also the fact that there's been very good, dry weather. Unusually dry weather. So that doesn't help".

Mr Darby said a number of actions from Minister Muir's 37-point-plan "have already been undertaken" to support the lough.

Looking to the future, Mr Darby said the Lough Neagh partnership is looking at a number of ways to address the issue.

"We have an environmental farm scheme we are working on at the moment, trying to encourage farmers to actually change their actions in terms of putting nitrates into the lough," he said.

"The sustainable catchment programme is a big follow on programme that we wanted to do, working closely with Minister Muir and Daera, and then we work closely with the catchment management people as well."

Mr Darby added that it is "important not to forget that blue-green algae isn't just about water quality, it also has an affect on biodiversity and the designation of the lough itself".

"For example, we are looking right now at working with Daera to predesignate the actual lough itself and trying to make it more effective," he said.

What impact does it have on Lough Neagh?

Mark Geddis/Getty A picture of Lough Neagh at sunset. A yellow and orange shine shimmers off the large expanse of water. A number of rocks can be seen at the dock.Mark Geddis/Getty
Lough Neagh is home to significant native species such as eel, trout and pollan

The largest freshwater lake in the UK supplies half of Belfast's drinking water and 40% of Northern Ireland's overall.

It is also home to the largest commercial wild eel fishery in Europe.

Sand-dredging, though controversial, has been a business on the lough for more than a century.

The lough and its catchment area is a vast ecosystem where species such as the curlew and the barn owl could be found in years gone by.

It has numerous environmental designations - special protection areas, special areas of conservation, areas of special scientific interest and Ramsar status.

Earlier this year, a team that monitors bird numbers around Lough Neagh, said they had noticed a "visible decline" in bird life around the lough.

A lough with blue-green algae present in the water. There are trees surrounding the lough. There are water reeds dotted across the lough and a brown wooden platform to the left.
The NIEA says the season's first confirmed case was reported on 2 April at Martray Lough in Ballygawley, County Tyrone

The NIEA said it was also monitoring potential sightings being circulated on social media.

The season's first confirmed case was reported on 2 April at Martray Lough in Ballygawley, County Tyrone.

A second confirmed case followed in Ballysaggart Lough (Black Lough), in Dungannon, which was initially reported on 9 April and subsequently verified on Tuesday.

With the recent good weather, the Department for Agriculture, Environment and Rural Affairs (Daera) previously said it was "no surprise that we are beginning to see algae-blooms re-appear again this year".

Pacemaker Andrew Muir is wearing a navy blazer, blue shirt and multi-coloured bow tie. He is wearing round glasses. he is standing outside and the background is slightly blurred behind himPacemaker
Environment Minister Andrew Muir says there are "no quick fixes" to blue-green algae

A spokesperson for Daera said Minister Andrew 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 reappear again this year, particularly with the good weather," the spokesperson added.

They noted that the "scale and severity of blooms in the months ahead will depend on a number of factors, including weather conditions".

The minister encouraged members of the public to report any suspected blooms using the Bloomin' Algae App.

He said people submitting photographs and locations could help scientists in verifying blue-green blooms and updating the Daera Blue-Green Algae Map Viewer.