A Pacific invasive alga (Rugulopteryx okamurae) has now colonized three sites…

June 25, 2026Cantabrian mixed forests

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A Pacific invasive alga (Rugulopteryx okamurae) has now colonized three sites along this coast, from Hondarribia to Guéthary, with the northernmost record appearing just last summer. The species first arrived in Europe in 2002 and has been expanding steadily southward; its presence here marks a significant range extension into waters that were once beyond its reach.

On southern Iberian shores, this brownish-red alga smothers native wracks and the dense invertebrate communities they shelter. Early summer is when its growth peaks most visibly, and the incoming year will likely bring further spread as water temperatures and seasonal conditions favor its establishment. The ecological consequences of displacement — reduced habitat complexity, shifts in food webs, loss of breeding ground for small crustacea and fish — remain poorly quantified but are certain to accumulate as the invasion deepens.

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