Rugulopterix okamurae seaweed in Tarifa, Andalusia

In Tarifa, Andalusia, the town hall says it doesn't have the means to remove the seaweed. | María Altamirano

Andrew EdePalma21/01/2025 09:23
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Rugulopterix okamurae is a species of brown algae native to the Pacific but which is invasive in the Atlantic and the Mediterranean and now threatens the Balearics. This seaweed colonises the seabed until it completely covers it. As it is not desirable as food for fish, it causes an exodus that reduces biodiversity. Its capacity to reproduce is so high that it constantly releases plant remains that come to the surface and are transported by the currents to the coast, where they end up covering entire beaches.

Since it was detected in Ceuta in 2015, it has proliferated on the Andalusian coast - the most affected area of Spain. It is also present in Murcia and Valencia. In Tarifa, Andalusia, the town hall says that it is unable to pay for its removal from the beaches. In Mallorca, the alarm bells went off at the end of last year when the alga was detected in the port of Barcelona.

Fiona Tomàs, a researcher at the IMEDEA Mediterranean Institute of Advanced Studies, believes that the shipping routes from Barcelona could lead to it being introduced to the Balearics. With an economy as linked to the sea as the region is, "we must prevent it from reaching our coasts". "We must act in time because we have the knowledge and we can carry out effective preventive management to avoid an invasion or, at least, minimise its impact."

María Altamirano, professor of botany and plant physiology at the University of Malaga, says: "Although it has not yet been detected, the Balearic Islands are a highly favourable area for it to proliferate. The authorities should look at minimising its spread." In Catalonia, there has been a monitoring system for invasive algae for more than 20 years. Such exhaustive control doesn't exist in the Balearics.

She explains that "quarantines" can be applied if the alga is found. "It is important to inform all people at sea how to identify it, so that they can notify the authorities. It quickly colonises everything, and then nothing can be done."