SCUBA June 2025 issue 156 | Page 16

Paul Naylor takes a closer look at two contrasting species of nudibranch
CRITTERCONFIDENTIAL

Colourful creatures, colourful lives

Rainbow Sea Slug( Babakina anadoni) and Grey Sea Slug( Aeolidia filomenae)

Paul Naylor takes a closer look at two contrasting species of nudibranch

Rainbow sea slug found in a rockpool. The small limpet it is crawling over shows its size

We are blessed with having well over 100 species of nudibranch sea slugs living around our shores and, understandably, these amazing animals are a big hit with divers. This month’ s Critter looks at two species that seem rather different at first glance but have much in common.

First up is what must be the most colourful of the lot, the aptly named Rainbow Sea Slug. I think perhaps the best way of describing it is to say it looks like it’ s been drawn with fluorescent highlighter pens! A southern species, it had not been seen further north than Spain before 2022. In that year, a Seasearch diver spotted one in the Isles of Scilly and then one was found on the shore in Cornwall. They have been seen increasingly often since, and the one shown here, thought to be the first sighting in Devon, was
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Grey sea slug at full stretch, moving towards its next meal