Overview
- Visitors raised alarm over murky, brown water at Porthdinllaen in Gwynedd during the Bank Holiday weekend when swimmers posted photos and reports.
- Natural Resources Wales sent officers to inspect the bay and concluded the discolouration was not a sewage leak but a natural algae bloom.
- The agency identified the organism as Phaeocystis, a common, non-toxic, bloom-forming algae that can create brown, frothy scums on the sea surface.
- NRW said recent strong sunlight and warmer temperatures likely helped the bloom form while high beach attendance increased public notice and concern.
- The body advised anyone worried about water quality to use its 24/7 incident line or online form and stressed that reporting helps it track real pollution events.