Jellyfish surge on Spanish beaches prompts warning for tourists

Independent

01-04-2025

Tourists visiting Spain and its islands are being warned of an increase in jellyfish washing up on its popular beaches ahead of the peak summer season.
Spanish news outlets, such as the Majorca Daily Bulletin and Canarian Weekly, are warning beachgoers of larger amounts of jellyfish, including a jellyfish-like creature that can cause powerful pain, appearing on the Spanish shoreline.
Rising sea temperatures and climate change have been identified as the cause for a higher volume of jellyfish appearing on Spanish coastlines, prompting swimming bans in recent years.
Last summer, nearly 7,500 swimmers sought medical treatment for jellyfish stings across some of Spain's most popular beaches on the Catalan coast, a 41 per cent increase from the previous year.
Most of the jellyfish that were spotted along the Catalan coast are relatively harmless species, including the fried egg (Cotylorhiza tuberculata) and barrel (Rhizotoma pulmo) jellyfish.
However, local authorities were also forced to close two beaches in Tarragona, Catalonia, in July 2024 after Portuguese man o' war (Physalia physalis) were spotted. While not technically jellyfish, the colonial hydrozoan's sting can be very painful.
The UK's Wildlife Trusts says the Portuguese man o' war can be identified as a 'large translucent purple float, the crest tipped with pink, and long blueish-violet tentacles.'
They can be seen bobbing on the surface of the sea, sometimes caught in mats of seaweed, but lose their colour quickly after washing up, and can appear translucent with just a tinge of purple after a while ashore.
It's the creature's tentacles that beachgoers need to watch out for, as they can sting long after the animal has died.
This year, warning flags have already been raised over in the Canary Islands at Las Teresitas Beach in Santa Cruz de Tenerife after several Portuguese man o' war was spotted on the shore, Canarian Weekly reports.
The marine creature has also been spotted on the Costa del Sol 's beaches, with members of the Aula del Mar Mediterráneo Foundation recently detecting specimens of Physalia physalis in the Mediterranean Sea off the Costa del Sol in Marbella (Puerto Banús), Fuengirola and Benalmádena, Sur in English said.
It added that the Portuguese man o' war had been dragged to the Malaga coast from the Atlantic by recent storms that have been hitting the province since the start of March.
Climate change and rising sea temperatures are the most prominent factors behind the increase in jellyfish, Macarena Marambio, a researcher at the Institute of Marine Science in Barcelona, told The Guardian last year.
'The jellyfish are becoming more common and are increasing both their seasonal and regional distribution,' said Ms Marambio.
'Warmer seas aid reproduction and as a result, we're seeing increasing numbers of the purple barrel jellyfish.'
'All the research shows that the numbers are cyclical and some years jellyfish are much more numerous than in others,' she said.
'However, what we're seeing in the Costa Brava is the cycles are getting shorter. The cycle of years with abundant jellyfish is shortening in some species from eight or 10 years to just two.'
She added the focus was on the Catalan coast because there was more data available but there were similar increases in jellyfish populations elsewhere in the Mediterranean.