Brown algae is attacking Moroccan beaches!

The golden beaches of Portugal’s Algarve region have been completely covered in tonnes of brown algae for days, much to the chagrin of summer visitors. This non-native algae (scientific name: Rugulopteryxokamurae), classified by the European Union as an “invasive alien species”, was discovered in 2015 on the Spanish coast of Andalusia. Some sources describe the spread as having first started on the beaches of Sebta before spreading and reaching the beaches of Tarifa, M├ílaga and Granada.

So, according to the Spanish media El Pais, more than 5,000 tons of this brown algae were collected on Sebta Beach in 2015. Because of its similarity to other Mediterranean species, scientists believe that the emergence and spread of this invasive species may have continued. for several months without notice. However, the negative impact of these algae is potentially serious.

Local wildlife is in danger

At this stage, biologists assure that the species is not toxic to humans. On the other hand, its consequences for the local aquatic fauna are very worrying. A study carried out in the Jbel Moussa Marine Protected Area between 2015 and 2019, for example, was able to establish that these brown algae developed rapidly to the detriment of the coralligenic habitat, the structure of which was altered by the regression of other native species.

“These species are sensitive to rising water temperatures and have already undergone gradual regression due to anthropogenic disturbances (due to human activity, ed.) and previous biological invasions. All of these factors may have reduced competition in this area and contributed to the impact of Rugulopteryxokamurae on this area,” the authors of the study stress, who also point to “the need for rapid administrative response to strengthen efforts to mitigate the consequences of this protected habitat.”

Impact of fishing

Faced with the recent appearance of brown algae on their coasts, Portuguese fishermen have not forgotten to express their concern. “Seaweed can seep into the net, which prevents them from catching fish,” Fabio Matos of the Barlavento Fishermen’s Association in Portugal told Euronews.

Due to their texture, these brown algae are not eaten by fish, so their spread is not controlled. So, in addition to other invasive species that have already changed the balance of the Mediterranean Sea, there are also these algae that spoil the pleasure of swimmers and pedestrians. According to experts, the algae got into the Mediterranean Sea by clinging to the hulls of ships or in ballast water (used on board ships to stabilize them before unloading after arriving in port). Therefore, its appearance at the level of the coast of the Strait of Gibraltar is not insignificant in view of the intense sea traffic that the area experiences.

Urgent measures

“The current status of the distribution of this invasive alien species on the Moroccan coasts and beaches of the Mediterranean Sea is not yet precisely established. In view of its negative impact on aquatic fauna and flora at the level of marine protected areas, as well as on tourism and fishing activities, it would be advisable to establish accurate mapping to monitor the spread,” says Housin Nibani, a biologist. and President of the Association for Integrated Resource Management (AGIR).

“Also in view of the increase in traffic and accidental introductions of exotic species, it is vital to increase preventive measures by strengthening, in particular, measures to control the deballasting of ships. Otherwise, taking into account the size and characteristics of the Mediterranean Sea, it remains difficult to fight the emergence of invasive species without creating a collective and coordinated effort involving a maximum of coastal countries,” the same source concludes.

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