Costa Brava resorts in Spain’s north-east are struggling to cope with an influx of jellyfish as rising sea temperatures facilitate reproduction and drive species farther north.
Between May and August almost 7,500 people on the Catalan coast sought medical attention for jellyfish stings – a 41% increase on last year. The stings are painful and can have unpleasant consequences for anyone with compromised immunity.
Climate change and rising sea temperatures appeared to be the crucial factors behind the increase, said Macarena Marambio, a researcher at the Institute of Marine Science in Barcelona, whose records of jellyfish activity in the area go back 20 years.
“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 are shortening in some species from eight or 10 years to just two.”
While Marambio points to the climate crisis as the key element, overfishing – which reduces predators – and the construction of breakwaters, ports, artificial beaches and marinas also play a part. This is because human activity reduces water quality and jellyfish are among the few species that can thrive in areas such as the port of Barcelona.