Fishing and tourism sectors in southern Spain fight a common enemy: An invasive species of algae

Its ability to survive is remarkable. It lives attached to the rocky sea bottom, but it is also able to thrive in suspension, floating in the drift. It can reproduce through spores and by offshoots, each one able to generate hundreds of new individuals. Its multiplication seems infinite if one considers that in a single square meter there can be thousands of them. The seaweed Rugulopteryx okamurae, originally from Asia, arrived in the Spanish north African exclave of Ceuta in 2015 in the ballast waters of a ship. It took just one year to cross the Strait of Gibraltar. Aided by climate change, in less than a decade it has ravaged the seabed of much of the coast of Cádiz, reducing biodiversity, hitting commercial fishing, and causing problems for tourism. The western Costa del Sol is its new victim. “The impact is total,” says María Altamirano, professor of botany at the University of Málaga. “It’s like when a fire ravages a natural park, but as this is unseen, hardly any action is taken.”

Andalusia is, for the moment, the most affected region of in Spain, but the presence of Rugulopteryx okamurae is already beginning to become a problem on the coasts of areas as varied as Alicante, Almería, the Canary Islands, Murcia and Bilbao. The fishing fleet is desperate and local councils are spending their budgets on eliminating the masses of seaweed that reach their shores, which generate thousands of tons of waste. The figures speak for themselves: in Estepona alone, more than 18,000 tons have been removed since 2020, according to data from the City Council, which spends €1 million each year on clean-up operations. In Casares, which has just 2.2 kilometers of beach, last April 460 tons of algae were removed after being washed ashore by intense westerly winds. The town’s delegate for beaches, Noelia Rodríguez, assures that removing them requires an “extraordinary effort” in personnel and expense. And it is something that happens almost daily, from Conil to practically the city of Málaga, a stretch of over 200 kilometers (124 miles) of coastline. And under the sea, the species is already colonizing protected nature reserves such as Cabo de Gata, in Almería.

Researchers Sandra Mogollón, Mariana Zilio, Eva Buitrago, Ángeles Caraballo and Rocío Yñiguez have calculated that Rugulopterix okamurae causes €3.3 million ($3.52 million) in losses for a municipality like Tarifa (which has fewer than 20,000 inhabitants and where in 2020, 2,300 tons of algae were removed), as they indicate in the conclusions of their study The economic impact of Rugulopteryx okamurae. “Especially in the fishing industry,” say the scientists, who emphasize that their model could be applied — with modifications — to other territories to account for the overall impact on the fishing or tourism sectors.

Professor Altamirano, who is also vice-president of the Spanish Society of Phycology, clarifies that “there is not a single civil servant who has stopped eating because of the algae: the focus should be on the fishing sector.” She believes that given the impossibility of acting where the algae is already established, measures must be implemented “now” to prevent it from continuing to spread to other places. The Ministry for Ecological Transition — which included the species in the Spanish Catalog of Invasive Alien Species at the end of 2020 — launched a control strategy in 2022, but it has not been very successful.

While tourism still looks askance on the issue, the fishing fleet has been in a tunnel for years from which it doesn’t quite know how to emerge. “The species has covered all areas up to 50 meters deep with sunlight on our coast. The transformation of the ecosystem has been brutal,” says Nicolás Fernández, manager of the Federation of Fishermen’s Guilds of Cádiz. The spokesman says that the sea urchin has disappeared from Tarifa, like the octopus has from the entire area around Cape Trafalgar: where once 1,000 tons were caught annually, now there are hardly any specimens left. There are even more chilling data: from 800 tons of sablefish caught in 2015, the figure dropped to just 600 kilos in 2019, a reduction similar to those of other species such as blackspot seabream.

The fleet competes in an increasingly small and depleted fishing ground because along the rest of the coast they are catching algae instead of fish. They then spend weeks cleaning their nets, or have to throw them away and spend €3,000 on new gear. That’s why many boats end up in the scrapyard. They are no longer profitable. The regional government of Andalusia has offered occasional aid, but the fleet is asking for more research resources, clear instructions on how to act, or to be allowed to modify their activity. They want to redirect it to tuna fishing, a species that has recovered “enormously” and even “already has a resident community in the Strait.” “This is a very serious issue in which the administrations have neglected their functions,” says Fernández.

Thousands of tons per year

“It’s insanity. A real disaster,” insists Daniel Gómez, councilman for beaches in Mijas, a town in Málaga where last year alone over 4,000 tons of this invasive species was removed from its 14 kilometers (8.7 miles) of coastline. Gómez affirms that, for the moment, although the decomposing algae generates unpleasant smells and attracts sea lice, tourism is unaffected “because an enormous effort is made to keep everything clean.” “One day you clean and the next morning everything is covered in it again. And the worst thing is that this has come to stay,” stresses the councilman. Operators in Marbella, for example, start their days at 5 a.m. with an arsenal of machinery with the aim of leaving the beaches clean. Removing the vast mats of algae — 1,000 tons on average annually — has already cost over €3 million, according to municipal sources.

Sometimes there is so much that it is impossible to remove all the organic debris, which for the City Council “can generate a negative image of the beaches, both for residents and tourists, and can also pose a problem for beach services such as sunbed operators or beach bars.” In popular tourist municipalities such as Benalmádena, Torremolinos, or Málaga, there have only been a few small incidents involving Rugulopteryx okamurae, but everything indicates that soon they will also have to get used to them and incorporate into their annual budgets the cleaning of beaches and the cost of transferring the algae to treatment centers.

In the past few years, each municipality has managed the collection of algae in its own way, but since March the Municipal Community of the Costa del Sol has taken charge of its transport to the Environmental Center of Casares, reducing the high expenses for local councils, who pay €42 per ton. Until now, Rugulopteryx okamurae was treated there like any other solid urban waste — that is why there are no statistics — but now it will be handled as pruning waste. This will make it possible to turn it into compost, sell it, and thus recoup some money. There is also research underway to use the algae as a construction element in cosmetics or even for footwear, although these have so far met with little success.

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