Leathery Sea Squirt Steyla clava
Sea squirts are animals shaped like a stout bag with two openings (siphons). This species is differentiated from other sea squirts in the UK by being solitary, with each individual having its own basal stalk. The species was probably introduced in 1952 on the hulls of warships returning after the Korean war. It can be found on the south and west coasts of England as far north as Cumbria and in abundance in certain parts of the Solent in southern England and parts of Loch Ryan and other scattered Scottish localities.
Large populations dominate and displace other species through competition for food and space. It is also a fouling pest on ship hulls and aquaculture infrastructure.
If you are a regular scuba diver, boater or beach comber and are interested in recording species this new app for smartphones has launched http://www.brc.ac.uk/sealife_tracker/ . The Sealife Tracker project aims to collect much needed data on both invasive and climate change indicator marine species around the UK coastline.