Analysis of nearshore samples from five sites identified 69 phytoplankton species across three groups: cyanobacteria, diatoms and dinoflagellates. Diatoms were the most diverse with 46 species, followed by dinoflagellates with 22. Only one cyanobacteria species was recorded, but Trichodesmium erythraeum dominated, accounting for 99.5 to 99.9 per cent of the community.

The discolouration was first observed on April 4 and April 5, when green water, surface foam and occasional pinkish purple patches appeared. Small fish were also found dead along the shore, affecting the beach’s appearance and raising concerns among visitors.

Authorities said the phenomenon recurs irregularly, driven by hot weather and light winds that allow algae to accumulate near the coast. Cleanup and monitoring measures have been deployed to ensure beach safety.