Thousands of tons of invasive seaweed ‘overwhelming’ Spanish beaches | Invasive species

Thousands of tons of aggressive invasive algae in Southeast Asia accumulate on the beaches of the Strait of Gibraltar and the southern coast of Spain in what local environmentalists say is a major threat to the biodiversity of the region.

Since May, the local authority of Cádiz has eliminated 1,200 tonnes of the algae Rugullopteryx Okamurae De la Caleta, the most popular beach in the city, including 78 tonnes in a single day.

“We are completely overwhelmed. This is an environmental disaster, “said José Carlos Teruel, head of the Cádiz municipal council beaches. “Whenever the wind is in the west, we know that we are in another wave of algae.”

As with many other invasive marine species, the algae is supposed to arrive in the ballast tanks of ships which cross the Suez canal and then unload their tanks in the Mediterranean.

In just over a decade, the species colonized the Strait of Gibraltar, a large part of the southern coast of Spain, Canary Islands, Azores and, further north, from the Cantabrian Sea and the Basque Country.

“It was spotted for the first time 10 years ago in Ceuta, Spain in North African enclave, by a researcher from the University of Málaga, but the authorities are still too slow to react,” said Juan José Vergara, professor of biology at the University of Cádiz.

“In the first phase of an invasion like this, it can be controlled. It is like catching cancer very early before spreading,” said Vergara, adding that what washes is a fraction of what is underwater.

“But now, its scale makes it impossible to control. In other algae invasions, we have seen things come back to normal after a period of 10 to 15 years, but many scientists say they have never seen an invasion on this scale.”

Algae has a major impact on the local economy, first on tourism in Cadiz and Tarifa nearby, a popular city with windsurfing, and on fishing because it traps the nets and lines of fishermen and also sucks oxygen out of water. Then there is the cost for the taxpayer of elimination.

The most worrying is perhaps its impact on biodiversity. On the Caleta beach, algae hunted many indigenous plants. It is not clear if the damage is temporary or irreversible.

The algae is attached to rocks and other surfaces and is also floating, destroying indigenous algae species. It has no predators in the region and its ability to reproduce both sexually and asexual and absorb toxins, it is practically impossible to eradicate, according to experts.

Currently, algae are thrown into landfill sites. Vergara said that a local company recycling algae in drinking containers or to be used as fuel and fertilizer asked for permission to use Rulelopteryx Okamuraeas as a biomass to produce energy.

However, the Spanish law on invasive species prohibits their commercial exploitation unless they constitute a threat to health and security or to continue their eradication, a warning which seems to apply to Rulelopteryx Okamuraeas.

This week, the Andalucía government launched a four -part plan to deal with the crisis according to research, monitoring and education, and which includes options to recycle algae.

To use it as a biomass, the regional government will have to negotiate with the Spanish Ministry of the Environment, but Vergara said that even if an agreement is concluded, it can only be part of the solution.

“It is an interesting idea, but I doubt that it can eradicate or even considerably decrease the intensity of the invasion when hundreds of thousands of tonnes can wash on a single beach,” he said.