Marine heatwave in Irish waters expected to bring more jellyfish

A MARINE heatwave being experienced off the coast of West Cork brings warmer waters for swimming but is also likely to bring increased jellyfish blooms. 

The marine heatwave has seen water temperatures on Ireland’s Atlantic coast rise sharply, hitting temperatures of up to 18C. According to the New Scientist magazine, the North Atlantic ocean has experienced record-breaking temperatures for the past three months. The US National Oceanic and Atmospheric Administration categorises the region as being hit by a category 4 (extreme) marine heatwave.

While bathers ands swimmers are likely finding the waters more comfortable, the temperatures are likely to bring in the bather’s bane: jellyfish. The warmer water is likely to see blooms of larger jellyfish populations in warmer water, and a larger population of toxic jellyfish.

Prof Andrew Wheeler, head of geology at the school of biological, earth & environmental sciences (bees), University College Cork, said:  ‘There are several other factors but we have seen a strong correlation between water temperature and jellyfish population.’

And Prof Wheeler said that while there is obviously enjoyment for swimmers, there are serious long-term concerns. Many organisms and ecosystems have problems responding quickly to the warmer temperatures, says Prof Wheeler, with many having a lower tolerance to the heat. 

Long-term, Prof Wheeler warned this can result  in a migration of some species north and out of Irish waters. 

‘What is more interesting is the long-term trend. The facts are clear that our oceans are warming up. Climate change is happening in the oceans, and is having an impact on the organisms there … changes to food webs can be quite detrimental to existing ecosystems,’ he said.

‘If we are concerned about the marine life, it is up to us to mitigate climate change.’