Rare Rainbow Sea Slug Discovered In Falmouth Rock Pool

A rock pooler has found a rare sea slug while searching around the coast of south Cornwall.

Vicky Barlow was poking around the pools of Falmouth when she found the rainbow sea slug, usually found in warmer waters.

According to experts there have been only three previous sightings of the creature in the UK and this was the first in a rockpool.

The first sighting is thought to have been in 2022 off the Isles of Scilly.

“There have been a handful of sightings by divers and snorkelers since but, as far as we can tell, this is the first time this species has been found by a rock pooler in the UK,” said marine biologist Dr Ben Holt of the Rock Pool Project.

The rainbow sea slug, or Babakina anadoni, is a member of the aeolid nudibranch family, which are characterised by their bright colours and unusual shapes, he said.

It is usually found in warm sea waters off the west coast of Spain, Portugal and France.

Spotting the sea slug was part of a pattern of “massive changes” in sealife seen around the South West over the last five years, said Dr Holt.

“It’s an amazing find and I expect we will see more of them,” he said.

“It is also quite remarkable because rock pools are quite a harsh environment with the tide going in and out.”