An uncommon Sea Hare, Aplysia fasciata, has been discovered in September, October and November in the UK. Another unusual and exciting find was a large common Thresher Shark, found in Cornwall.
Aplysia fasciata, rarely seen in the UK, is larger than the common species Aplysia punctata, reaching up to 40cm long (rugby ball sized!) and can weigh up to 2kg! It is usually found on the Atlantic coasts of France, Spain, Portugal and West Africa. Sea hares are large herbivorous sea slugs, feeding on a wide variety of seaweeds. They have a small internal shell and when disturbed, release a cloud of purplish ink. Aplysia fasciata is very dark brown to black in colour. As well as the sea hares themselves, large egg masses, up to 30cm have also been found on the Devon coast.
A skipper, while fishing in the English Channel, south of Land’s end, hauled up a large, female common thresher shark (Alopias vulpinus). It was found to weigh 510 kg (1122 lb) and was 475 cm (15’ 58”) long, although thresher sharks are known to grow to 573 cm (18’8”). Thresher sharks are one of the largest of the approximately 28 sharks found in British water. Thresher sharks have long tails, the same length as their bodies and use these tails to move the fish, usually pilchards, herring and mackerel into tight shoals before attacking. There have been other thresher shark findings recently in Cornwall such as the large shark found in Charlestown which was approximately 400kg (881lb) and 463 cm (15’ 20”) long.