Jellyfish swarms invade British seas

Barrel jellyfish "the size of dustbin lids" are being spotted in huge numbers across the coasts of Devon and Cornwall, reports Matt Evans

Gloucestershire floods

Barrel jellyfish, or rhizostoma pulmo, have returned to our shores in force. The jellyfish, common in the Irish Sea, has been spotted across the shores of Devon and Cornwall, with the Western Morning News reporting that Wildlife cruises in Falmouth have spotted hundreds floating with the current simultaneously. 


These aquatic monsters can grow up to 35 inches across and their tendrils can stretch up to six feet long. The venom in the Barrel jellyfish’s sting is not powerful enough to seriously harm humans, but beach-walkers and fishermen are being advised not to touch them. 

The abundance of these visitors can be attributed to warmer weathers meaning a larger stock of plankton to feed on, as well as the decline of the jellyfish’s traditional predator, the leatherback sea turtle.

“The leatherback turtle is struggling at the moment, which means there are less of them to eat the jellyfish”  Steve Hussey, of the Devon Wildlife Trust, told BBC News.  “We’re getting reports from fishermen that they’re catching more jellyfish than fish”.


The jellyfish swarms gathered in May last year in similar numbers, although the earlier sightings of jellyfish may indicate many more are on their way this year.