Asian seaweed continues its expansion along the Andalusian coast for the ninth consecutive summer.

Ivan Martin

Malaga, Aug 8 (EFE).- The Asian seaweed, or Rugulopterix okamurae, continues its invasion process for the ninth consecutive summer in Andalusia, a region where it has colonized four of the five coastal provinces—Cadiz, Malaga, Granada, and Almeria—and has only encountered problems establishing itself in Huelva.

This organism was first detected in Europe in 2002, in France, in 2015 it settled in Ceuta, and in 2016 it took advantage of the opportunity to spread to both sides of the Strait of Gibraltar, invading much of the Iberian Peninsula's coast. Experts attribute its arrival to the ballast water contained in ships coming from the Pacific Ocean, where it originates.

The Andalusian coast has already experienced three invasion attempts by different species of algae, but the current one is the most damaging to southern waters, María Altamirano Jeschke, professor of the Department of Botany and Plant Physiology at the University of Malaga, explained to EFE.

The thousand and one lives (to live) of the invasive Asian algae

There is currently a significant presence of Asian seaweed in the western part of the province of Málaga and in Cádiz, where 10,000 kilos were removed at the end of July in the municipality of La Línea de la Concepción.

Regarding the state of the other Andalusian provinces, the expert explained that Huelva has sandy bottoms that are not conducive to this algae; Granada is largely invaded; and Almería has a large presence in Aguadulce, Roquetas de Mar, and the Cabo de Gata Natural Park.

Altamirano highlighted the homogenization of the seabed in terms of algae, an ecosystem whose diversity has generally been reduced by up to 95 percent in some areas.

He also highlighted this organism's ability to settle without anchoring to the bottom, allowing it to thrive in suspended waters. In situations like Huelva's, it can be harmful if this algae manages to establish itself without needing to cling to the soil.

Remove them with caution

In light of the growing expansion of this species, the Andalusian Regional Government's intervention manual for this invasion has recently been published, outlining how to deal with it and the uses to which the specimens removed from beaches should be put.

Regarding the possible uses of these algae, Altamirano highlighted the reuse carried out in Melilla, where the removed specimens are used to generate energy and contribute to the circular economy.

According to the professor, it is essential to "inactivate" the removed specimens to prevent the invasion from continuing and to be able to reuse that biomass for similar purposes to those used in Melilla, turning a problem into a benefit.

A detriment to fishing

Fishing activity has been affected by the expansion of this species, which has become widespread and currently complicates artisanal practices and, for the most part, trawling operations.

Andalusia calls on the government to be more involved in the fight against invasive Asian algae.

The algae make it difficult for fish to access fishing nets and even force fishermen to bring them to the surface to dispose of them and then repair their work tools.

Because of the harm caused by Asian seaweed, fishermen try to dispose of it in a safe place, such as a port, but the urgency of their work often means they dump it in different areas where they operate, which increases the spread and invasion of the species.