Invasive Japanese algae spreads rapidly along Sines coastline

Researcher Joaquim Parrinha, of MARE|ARNET, warns that the invasive alga Rugulopteryx okamurae has grown sharply along the Sines coast over the past three years, first detected in Setúbal a decade ago. Originally from the Northwest Pacific and introduced to the Mediterranean via oyster aquaculture, it has spread from the Algarve northwards as sea temperatures rise, forming dense underwater masses down to 12 metres. These blooms block light and reduce oxygen, harming native species such as coralline algae and laminaria. In July 2025 the government approved a national strategy including mechanical removal and monitoring.

This appeared in the Pulse of 3 September 2026 — Read that edition →