Wild Wednesday - Corpheila sea slug
This week we're heading beneath the waves right here on our West Sussex coastline to shine a light on one of our region's tiniest but most extraordinary marine residents - the Corpheila sea slug, scientific name, Coryphella browni.
Often missed due to its size, this delicate sea slug is a brilliant reminder that even the quietest corners of our shoreline hold wildlife wonders.
West Sussex forms part of the 'species' known range' along the south coast of England. This refers to the specific, mapped geographical area or habitat where individuals of a particular species have been documented to live, breed and travel throughout their lifetime.
Whether you're exploring the rocky fringes near Littlehampton, wandering Chichester Harbour's quieter inlets, or snorkelling off Selsey's rich marine slopes, the Corpheila sea slug could be just below the surface - hidden, but not absent.
This species is instantly recognisable once you know what to look for:
- a translucent white body that glows in sunlight
- rows of red or brown cerata (finger‑like projections) tipped in bright white
- a total length of only a few centimetres
Underwater, this colour palette gives the slug a flickering, flame-like appearance.
One of the Corpheila's most remarkable traits is its ability to feed on hydroids, small stinging marine animals. Instead of being harmed, it absorbs the hydroids' stinging cells into its own body, storing them in its cerata, and using them as a defence against predators - an impressive survival strategy nestled right here in our local waters.
Snorkellers and divers at Littlehampton East Beach, Worthing, and Pagham Harbour may spot the Corpheila clinging to hydroid colonies or drifting gracefully in gentle tidal currents.
The fact that it has been explicitly recorded along the south coast of England, including Sussex waters, makes this one of our region's most exciting hidden gems.
The Corpheila sea slug is an indicator species for healthy hydroid and invertebrate communities. Its presence suggests good water quality, thriving food webs and complex micro‑habitats supporting both predator and prey.
For a coastline like ours - often assumed to be murky, this species is a vibrant ambassador for the surprising biodiversity of West Sussex's coasts.
The Corpheila sea slug may be miniature, but it embodies the magic of local marine life - beautiful, tough and intricately adapted to the underwater landscapes of West Sussex.
Next time you wander the coast or peer into a rockpool, take a moment. The waves might be hiding a small, shimmering miracle.