Jellyfish invasion blamed on climate change

An invasion of jellyfish plaguing holiday-makers in the Mediterranean has been put down to global warming, with the hot dry weather bringing the creatures closer to the shore.

Spain is worst affected, with some beaches closed as swarms of stinging jellyfish threaten swimmers.

Coastal waters are usually less saline and cooler than the open sea at 20-40miles from shore that jellyfish usually favour, keeping the creatures away from beaches and swimmers.

But this summer’s dry, hot weather experienced throughout Europe increased the salinity of coastal waters as well as its temperature, scientists from the marine conservation NGO Oceana said.

With low-flowing rivers bringing in less freshwater, the natural barrier that keeps jellyfish at bay broke down, they said.

Climate change could therefore not only bring more beach-going weather, but also remove some of the attraction of beaches as the sea becomes infested with the stinging invertebrates.

But climate change is not the only factor bringing swarms of jellyfish close to the beaches of Spain and other areas of the Mediterranean such as Sicily. As well as the creatures venturing closer to the coast in hot, dry weather, there may also be more of them.

Scientists pointed to falling numbers of the natural predators of jellyfish – turtles, tuna and other large fish. Overfishing is therefore also likely to contribute to the invasion, alongside warmer, less salty waters in a changing climate.

Water pollution may be another factor, as the animals thrive in coastal waters when concentrations of nutrients are high.

Jellyfish stings should not be rubbed with sand or a towel, Oceana advises, but cooled with ice wrapped in a plastic bag.

This is not the first time jellyfish are in the spotlight this summer – just last month, the wobbly creatures shut down a nuclear plant by blocking one of its cooling pipes (see related story).

More information about jellyfish can be found at the Oceana website.

Goska Romanowicz

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