This is a ‘Video of the mottled sea hare, Aplysia brasiliana, taken at CEBIMar, one of the marine laboratories of the University of São Paulo, located in São Sebastiao, São Paulo, Brazil.’
From WildLife Extra:
Aplysia fasciata is the largest and the rarest of the three species of sea hare found in the British Isles. It is an Atlantic species, found from the Channel to Angola (South-west Africa and to Brazil) and also throughout the Mediterranean.
It appears to reach its northern limit in Ireland and along the Channel coast of England. It is one of the largest sea slugs in the world. The other two British species are the relatively common Aplysia punctata variable in colour and growing to 20 cm; and Aplysia depilans with different shaped back lobes, brown or green and growing to a maximum of 30 cm.
An Aplysia fasciata specimen of 30 to 35 cm and weighing 1.5 kg was caught in Poole Bay, Dorset, in October 2007.
It was brought into the National Marine Aquarium where it is on show as a ‘Feature Creature’ in the recently refurbished Shallow Waters, Hidden Depths exhibit, where it is devouring large quantities of sea lettuce.
Becoming more common
There were several recorded in the Channel Islands in the mid-1800s, but the first one in mainland Britain was found in Salcombe Estuary, Devon, at extreme low water in February 1949. Another was found at the same place in 1997. They are very rare but have also been found in Ireland and Cornwall. …
While called sea slugs they are very different from garden slugs, being some of the most spectacular and beautiful of molluscs.
Sea Hare Turns Food into Chemical Weapons: here.
Sea slug Geitodoris planata in the Netherlands: here.