Five-year-old Charley and his dad Chris, who were new to the BioBlitz Battle group, said they initially thought the creature was “seaweed”.
“If it wasn’t for my son Charley chasing after a large crab, we wouldn’t have found it,” Chris said.
MBA said the species could grow up to 40cm (15.7in) long, weigh up to 380g (13.4oz) and were significantly larger than the more common Spotted sea hare (Aplysia punctata).
Russell said they found two of the sea slugs during the same session and while the team and children were excited, the parents were a “bit grossed out” because it looked “a bit weird”.
“When most people think of a slug, they think of a garden slug which are kind of boring, people know what those are and see them all the time, but this is a sea slug that is quite a unique thing to see,” Russel said.