North Coast bathing waters situation improves but caution still advised

Date published: 10 July 2023

The red flag advice against bathing at Portstewart, Castlerock, Downhill and Benone beaches on the North Coast has now been removed, however the public is still advised to be vigilant for pockets of blue green algae residue and scum along the shoreline.

This images shows a comparison between a typical green marine algae, which should not be confused for the blue-green/grey residues associated with Blue-Green Algae.

Samples taken by the Department of Agriculture, Environment and Rural Affairs (DAERA) and Northern Ireland Environment Agency (NIEA) throughout the weekend from the bathing waters in Portstewart, Castlerock, Downhill and Benone, show that the Blue-Green Algae has now dispersed and the waters are safe to bathe in. The local bathing water operators have confirmed that all red flag warnings have now been removed.

However, small pockets of scum and residue of the algae may still be on the shoreline and people should remain careful not to let their dogs ingest such material.

DAERA will now revert to its regular weekly monitoring of the bathing waters.

If you suspect there is blue-green algae:

  • Report it on the Bloomin Algae App: The Bloomin’ Algae App helps make reporting of blue-green algae easier and quicker, allowing environmental experts to respond faster and issue public warnings more efficiently. It enables users to submit a photo of an algae bloom on their mobile device, along with the location and activities taking place in the associated waters. Bloomin’ Algae App is free to download directly from Google Play or App Store. Find out more at the UK Centre for Ecology & Hydrology
  • If you don’t have Bloomin Algae App – email photos to NIEA: Report the bloom to the Northern Ireland Environment Agency. You can report any suspected blooms, including photos and details of location, to our e-mail or make contact through our incident hotline on 0800 80 70 60.

Notes to editors: 

1.  Follow DAERA on Twitter(external link opens in a new window / tab) at and Facebook(external link opens in a new window / tab).

3. All media queries should be directed to the DAERA Press Office or telephone: 028 9052 4619.

4. The Executive Information Service operates an out of hours’ service for media enquiries only between 1800hrs and 0800hrs Monday to Friday and at weekends and public holidays. The duty press officer can be contacted on 028 9037 8110.

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