Potentially toxic algae have been spotted growing in lakes that link to the city’s water supply.

Anglers have reported the presence of green algal bloom in recent weeks in the three Coolagh Lakes, which feed into the River Corrib, the city’s drinking water source.

An algal bloom is an overgrowth of algae that can be seen as green or blue/green streaks or slimy scums in water.

Some blooms can produce toxins, and their presence can potentially cause a risk to human and animal health, Galway City Council said.

This latest warning follows on from similar algae growth on waters near Menlo reported in the Galway City Tribune last November.

The City Council said it was investigating the latest reports of algae spotted in the water at Coolagh in late April and early May.

It said the water samples had been sent for analysis.

“Visual indicators at the time suggest that there may not be an environmental risk, however given the extended period of warm calm weather we will continue to monitor the situation,” the City Council said.

On this occasion the local authority blamed “unseasonal warm and calm weather” as the likely cause.

“We also remind members of the public, that algae blooms may produce toxins, and their presence can potentially cause a risk to human and animal health,” the Council said.

In November, Corrandulla-based Michael McGrath of Lough Corrib Angling Federation said the reports of green algae needed to be taken seriously.

He warned the toxic algae could morph quickly into a more dangerous blue-green algae bloom, which would threaten the city’s drinking water source.

Pictured: Algal bloom on the Coolough lakes near Menlo this week.