Invasive species threaten Mediterranean marine biodiversity

The Mediterranean Sea is facing significant ecological pressure from invasive species. A study coordinated by the Instituto de Acuicultura Torre de la Sal (IATS-CSIC) has tracked the widespread expansion of the pearl oyster Pinctada radiata. Originally from the Red Sea, this species has moved from sporadic sightings to a generalized expansion across the western basin, including the Spanish coasts from southern Catalonia to Almería.

Simultaneously, research from the Institut Mediterrani d’Estudis Avançats (IMEDEA) highlights how invasive macroalgae, specifically Caulerpa cylindraceai and Lophocladia trichoclados, are hindering the natural regeneration of Posidonia oceanica seagrass meadows. The study found that these invasive algae cause seedlings to develop fewer leaves and significantly less biomass, reducing essential energy reserves. Notably, increased CO2 concentrations failed to counteract these negative effects, leaving the seagrass vulnerable during critical life stages.