I’m Emma and I study BSc Conservation Biology and Ecology at the University of Exeter and I am currently undertaking an internship with The Rock Pool Project. I’m fascinated by nudibranchs and hopefully throughout this blog you will learn many new interesting facts about them! Don’t forget to keep yours eyes peeled whilst out rockpooling!
Background to nudibranchs:
There are over 100 different species of nudibranchs in UK waters! There have been many different species of nudibranchs discovered by The Rock Pool Project in both Cornwall and Plymouth, using iNaturalist. Nudibranchs are very important for the wider ecosystem as they are indicators about the health of the environment. Nudibranchs are a loved species around the world as they are one of the most varied species of marine life on Earth! When you are next rock pooling, keep your eyes peeled for a dash of colour, you never know what you may encounter!
iNaturalist divides nudibranchs into two major groups: Dorids and Cladobranchs.
Descriptions of different nudibranchs:
In this section I will talk in detail about all the different nudibranch species that The Rock Pool Project have discovered, which have uploaded onto iNaturalist. In total, the Rockpool Project have discovered 12 different species of nudibranch in Plymouth and Falmouth!
Rainbow sea slug (Babakina anadoni):
Rainbow sea slugs are an extremely rare species to find in rockpools around the Cornish coastline as they are normally found in warm waters off the coast of Spain, Portugal, and France. The rainbow sea slug is a member of the nudibranch family and are characterised by their vibrant colour and peculiar shape! To find out more information about the rainbow sea slug, visit the site.
A rainbow sea slug was discovered last year by a member of The Rock Pool Project team in Falmouth which went viral worldwide!
Sea lemon (Doris pseudoargus):
Sea lemons are a common species you’ll encounter in UK rockpools. They are a large and colourful sea slug found in rockpools around the UK and are up to 12cm in length. If you have found a sea slug with warty lumps, blotchy markings, and lemon in colour, you’ve most likely found a sea lemon (Doris pseudoargus). They breathe using feathery gills and are most common during the months of January to December.
Warty doris (Doris verrucosa):
Warty doris sea slugs are a rare species to find off the UK coastline. This species of nudibranch lives mainly under stones in the intertidal zone and gets it name from the tubercle shaped warts all over its body! The warty doris sea slug is in the family Dorididae and is a dorid nudibranch.
Sea slug (Aeolidiella alderi):
This species of sea slug has a very flattened and slender shape which can grow up to 37mm. The Aeolidiella alderi is pale cream in colour, with superficial orange pigment on its back! This species is native to northwestern Europe where it occurs in the intertidal zone and feeds on sea anemones. This species has an amazing set of oral tentacles on the head, which are longer than the rhinophores. In case you didn’t know, rhinophores are sensory structures which are able to analyse the chemicals dissolved in water around the sea slug!
Four-lined Polycera (Polycera quadrilineata):
Polycera quadrilineata, is a sea slug, a species of dorid nudibranch and a marine gastropod mollusc in the family Polyceridae. This species is smooth bodied and variably coloured nudibranch. The gills and rhinophores are translucent white, tipped with a dash of yellow! The four-lined Polycera can reach lengths of 20mm!
Crowned Aeolis (Facelina auriculata)
Crowned Aeolis is an aeolid nudibranch in the family Facelinidae.
Facelina annulicornis:
The body of the sea slug species is translucent with scattered spots of white pigment and around the mouth the skin has a rose-coloured hue. Both the rhinophores and oral tentacles are tipped with white pigment! This is a southern species found in the British Isles; however, records extend northwards along the west coast of Ireland to Donegal Bay and Portrush. The adults can grow up the 40mm in length!
Geitodoris planata:
This species is found mainly on southwest coasts of Britain but is uncommon on west coasts. This species is a shallow sub-littoral species on rocky coasts that feeds on sponges. This species is recognisable by the mottled orange, brown or purple colour and the warty mantle is predominantly brown or a dull purple. Adult Geitodoris planata can reach to lengths of 6.5cm!
The Hairy Spiny Doris (Acanthodoris Pilosa):
This species is easily distinguishable from other nudibranchs by its rounded, fluffy, and soft textured appearance. Acanthodoris Pilosa has long, soft, pointed papillae all over its back, which are usually uniform in length and colour. Colour of this species varies from white to brown and purplish brown to charcoal grey! This species is common all around the British Isles and it usually grows up to 3cm in length but can reach 7cm!
Polycera norvegica:
Polycera norvegica is a species of dorid nudibranch and is in the family Polyceridae. It is a smooth bodied nudibranch with two different colour morphs; the ground colour is translucent with yellow or orange tubercles, the spotted colour has smaller yellow spots and additional black speckles which may partially fuse into brown patches in some individuals. This species can grow up to 14mm in length!
Barnacle-eating Dorid: (Onchidoris bilamellata):
Onchidoris bilamellata has been recorded all around Britain and Ireland. It bears many club shaped projections on its mantle and has two ringed sensory tentacles on its head! This species can grow up to 4cm in length and are usually white with a brown pattern on the mantle. The species has many retractable gills which are speckled brown around the edges and arranged in a horseshoe shape.
Orange clubbed sea slug (Limacia clavigera):
Limacia clavigera is white in colour with yellow orange tipped processes that can grow up to 2cm in length! Two rhizophores (I talk about these earlier!) can be found on the back of the slugs’ head, that are tipped with yellow. This species of nudibranch also has three feather like gills which are located towards the rear end of the slug, which also have yellow orange tips. Limacia clavigera are found all around the British Isles, except the southeast.
Don’t forget to join in with The Rock Pool Projects’ Quest to win Bronze, Silver and Gold medals depending on the sea slug or nudibranch that you discover!
