The invasion of Brown seaweed (Rugulopteryx okamurae) is no longer something that appeared along the Atlantic coast of Andalucia, but is now all along the Costa Tropical.

—The arrival of the species into this area is probably down to sea currents and maritime traffic, including fishing activities – it was first brought up by fishing boats out of Motril in 2019.

Later, marine researchers at the Universidad de Granada and Aula del Mar noted its presence on the seabeds off Castell de Ferro and La Herradura. Now, there is not one municipality on Costa Tropical where it has not been found in shallow water off beaches between 0.5 metres and 15 metres down.

What Town Halls are worried about, perhaps more than what damage it causes to octonous marine flora like the seagrass, Posidonia oceanica, (commonly known as Neptune grass or Mediterranean tapeweeds) is that it gets washed up onto the beaches during the summer when they are packed with tourists.

The Mayor of one municipality at the eastern end of Costa Tropical complained that when it rots it stinks and attracts small flies and fleas, making unpleasant companions for beach users. Of course, it adds to the task of keeping beaches clean, increasing costs.

The Director of Aula del Mar, Julio de la Rosa, points out that it is precisely now when this species experiences its maximum growth period.

He says that the most affected areas are: Tesorillo in Salobreña, the Cerro Gordo in La Herradura and the beaches belonging to Castell de Ferro. However, it is the beaches with sandy seabeds that most attract this seaweed, such as off Playa Velilla in Almuñécar for example.

So what is the problem, apart from its a nuisance on beaches? Much like the grey squirrel that wiped out red squirrels in the UK, this Asian seaweed is crowding out autochthonous seaweed and the small invertebrates that lives in them.

Furthermore, when it rots in the water it contaminates it, producing a drop in oxygen in the water, making it difficult for species in general to survive.

(News: Costa Tropical, Granada, Andalucia)