In the summer, it was already found in Catalonia for the first time at the port of Llançà. Now it has been detected at the Olympic Port of Barcelona, as part of the invasive species monitoring work conducted by the Centre for Advanced Studies of Blanes (CEAB-CSIC) in collaboration with the Catalan Water Agency (ACA). This algae can cover depths from the surface down to thirty meters, harming native species and affecting activities like fishing.
Monitoring efforts for invasive species have enabled the detection of a new invasive algae on the Barcelona coast. It is Rugulopteryx okamurae, commonly referred to as the “Asian algae” since its introduction into the Mediterranean. The species, originally from the northwest Pacific Ocean and commonly found on the coasts of Japan, China, Taiwan, Korea, and the Philippines, is listed both in the Spanish Catalogue of Invasive Exotic Species and the EU’s list of invasive exotic species of concern.
The invasion of this algae, which has caused damage in various parts of Spain, such as the Andalusian coast (its colonization has been documented since 2015 in Ceuta and the Strait of Gibraltar), has been recorded from the start by the CEAB-CSIC invasive species monitoring group. This group collaborates with the ACA, part of the Government of Catalonia, as part of the marine exotic species prevention and monitoring program.
The species was first detected on the Catalan coast at the start of this summer, when researchers and lecturers from the University of Barcelona (UB) observed the early colonization of the first individuals at the port of Llançà during a fieldwork activity with students.
Following personal communication with UB researchers, the CEAB-CSIC team, led by the late Dr. Enric Ballesteros, validated these observations and conducted surveys in the area to characterize the invaded habitats, assess the extent of colonization, and monitor its progress.
Since then, the algae has spread to adjacent areas (sites in Llançà and Colera), colonizing the crevices of artificial blocks in ports and beaches in a scattered manner without showing massive substrate occupation. Data on this spread is collected and provided by both the CEAB-CSIC team, as part of the ACA’s invasive species monitoring program, and divers and other citizens who collaborate through citizen science initiatives (providing information later verified by the scientific team).
Now, the algae has been found in another location, far from this area: the Olympic Port of Barcelona. The CEAB-CSIC team has recorded its presence on the blocks of the submerged counter-breakwater at depths of 3 to 6 meters, covering approximately 15% of the surface. Regarding its introduction, researchers believe it most likely arrived via recreational boats.
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Ecological and Economic Impacts
This same species currently occupies photophilic seabeds in Etang de Thau (French Provence), Ceuta, Andalusia, northern Morocco, Marseille, the Azores, Murcia, Madeira, the Canary Islands, Alicante, and the aforementioned areas of the Catalan coast.
It has demonstrated significant invasive potential, being able to cover rocky seabeds from the surface to depths of thirty meters, even growing over other algae and marine plants. It can cause significant modifications to marine ecosystems, altering habitats and displacing or eliminating native species.
In addition to the incalculable impacts on marine biodiversity and food webs, direct economic losses caused by this species to fishing activities are currently estimated at over one million euros annually, not including the cost of cleaning beaches from the arrival and accumulation of vegetative debris.
Actions for Monitoring and Control
The initial actions, carried out in collaboration with the Catalan Water Agency (ACA), include:
- Increasing monitoring frequency in the locations where it has been observed, which currently, on the Catalan coast, correspond to the breakwaters of sports ports and their surroundings.
- Characterizing the colonized area (the surroundings and nearby zones of Colera, Llançà, and the Olympic Port) to define the occupied area and the algae’s distribution limits.
- Conducting seasonal studies of sites colonized by R. okamurae to identify its morphotypes (appearance, size, density…) during each season of the year and to understand its behavior depending on the characteristics of each area.
- When new possible locations are identified by other public or private entities, the ACA will carry out taxonomic identification, with support from CEAB-CSIC specialists, to confirm whether or not it is the invasive algae (as it is easy to confuse with native species).
- In the event of new colonized areas, the ACA will inform the Directorate General for Natural Environment and the Ministry for the Ecological Transition and Demographic Challenge, through the Generalitat of Catalonia’s working group on invasive species, to decide and implement control actions where necessary and feasible.
Monitoring Invasive Species in the Marine Environment in Catalonia
Since 1992, the Catalan Water Agency (ACA) has been a pioneer in developing marine invasive species monitoring programs. It does so in collaboration with the Centre for Advanced Studies of Blanes (CEAB-CSIC). As part of these programs, a surveillance network has been established with stations distributed along the entire coast, which consistently provide data.
The ACA studies the state of coastal water bodies concerning introduced species, the spread of relatively recent species, and monitors their colonization and evolution to prevent harm to native ecosystems.
When new species are detected, they are indexed and included in monitoring programs. Citizen science plays a key role in this effort, with initiatives like Observers of the Sea, which provide data that the CEAB-CSIC scientific team validates and supplements with data obtained directly from fieldwork at various points in the surveillance network. All verified information is provided to the ACA to support actions aimed at preserving aquatic ecosystems.
L'entrada The Asian algae Rugulopteryx okamurae detected on the Barcelona coastline ha aparegut primer a CEAB.