A large colourful sea slug found on rocky shores around the UK.
Top facts
Stats
Length: up to 12cm
Conservation status
Common
When to see
January to December
About
The sea lemon is a type of sea slug found in UK seas down to 300m and occasionally under boulders in rockpools on the low shore. They are often lemon-yellow in colour, but can be green, white or brown. Their body is covered in warty lumps and their markings are often blotchy. They have a ring of feathery gills near their rear end that they use to breathe. The sea lemon feeds on sponges, mainly the Breadcrumb Sponge. They lay a long ribbon of eggs which are laid in a coil with one end attached to the seafloor - creating a beautiful egg rosette.
What to look for
A large sea slug, up to 12cm long. Normally found under rocks or bounders in rockpools on the low shore or beneath the sea. They have a warty bumpy body, with yellowish and often blotchy colouration. Confusingly, they can also be green, white and brown.
The sea lemon's entire life cycle last only a single year. Juveniles appear in the late summer and grow into adults throughout autumn and winter. They then mate and spawn in spring before dying.