Visitors warned of blue-green algae at Bosherston Lakes

Natural Resources Wales (NRW) officers have identified blue-green algae at Bosherston Lakes in Pembrokeshire.

They have notified the landowners National Trust and warning signs have been installed at the affected lake advising people to ensure they and their pets do not come into contact with the algae or the water, and to maintain basic hand hygiene.  Pembrokeshire County Council has also been informed.

Blue-green algae naturally occurs in inland waters, estuaries and the sea. Blooms can form when their numbers become excessive. There are currently no blooms, but floating mats and rafts of algae have been detected.

It adds oxygen to water during the day but consumes it at night. This can lead to dangerously low oxygen levels which can suffocate fish and other creatures.

Bloom and scum-forming blue-green algae can produce toxins. These toxins can be very dangerous to animals. In humans, they can cause rashes after skin contact and illnesses if swallowed. 

Rod Thomas, Senior Environment Officer, of NRW, said:

“Our officers in Pembrokeshire have visited and tested the lakes, and found blue-green algae to be present at some areas of the Bosherston Lakes.

“There are no blooms at present, but current weather and site conditions are ideal for blooms to occur.

“Not all blue-green algae blooms and scums are toxic, but you can’t tell just by looking at them, so it’s best to assume they are and follow advice to avoid contact with it and the water.”

For more information on blue green algae visit the NRW website. https://naturalresources.wales/guidance-and-advice/business-sectors/farming/blue-green-algae/?lang=en

You should call NRW to report incidents of blue-green algal blooms or scums via our incident hotline: 0300 065 3000 (24 hours).