Huge Lion’s Mane Jellyfish Spotted Off Pembrokeshire Coast

Mr Morgan said he was swimming near Trefin Beach in Pembrokeshire when he spotted a tentacle in the water.

“Three turned into 10, then 20. They kept coming,” he said.

The jellyfish was so large that its tentacles appeared to “exceed the range of sight”.

Jellyfish Tentacles Spanned an Incredible Distance

Mr Morgan initially thought the animal was a compass jellyfish, which lives in British waters, but soon realised it was far too large.

“It must have been as long as a bus or a small train. I couldn’t believe it was that big,” he said.

According to the Wildlife Trusts, external, the lion’s mane jellyfish gets its name from its long tentacles, which Mr Morgan said “have all the beauty and bite of a lion”.

The species can grow up to 3 metres (9ft 8in) in length. Its tentacles, which it uses to capture prey, can extend beyond 30 to 36.5 metres (98ft 4in to 119ft 8in), making it one of the longest animals on Earth.

Marine Biologist Explains the Jellyfish’s Sting

Dr Cathy Lucas, a marine biologist at the University of Southampton, said Mr Morgan’s video shows the animal’s remarkable length.

“The tentacles are so long and thin that you might not be able to see them,” she said.

Dr Lucas recalled that, while working in the field in Scotland, a diver ended up with pieces of tentacle on him even though no jellyfish were visible nearby.

“It still stings after it’s cut,” she said, describing the sting as “uncomfortable” and “the worst in the UK”, although not dangerous.