A large cold-water jellyfish with a brown-red bell and a dense mass of fine trailing tentacles.
A brown to red bell, in northern waters commonly 30 to 50 cm across and occasionally much larger, with eight bunches of fine tentacles hanging beneath it. The tentacles reach several metres and are hard to see.
The sting is painful and leaves a rash, and for most divers that is the whole of it. The practical difficulty is judging the size of the animal from above: a diver who gives the bell a metre of clearance may still be inside the tentacles.
It is a cold-water animal of the North Atlantic, North Sea and North Pacific, most often met in late summer. A hood, gloves and a full suit cover what usually gets stung, which is the face, neck and wrists.
This entry carries no occurrence record. The animal is listed because it is a hazard a diver should be able to look up, and its range is given above, but none of the destinations this site holds data for is inside that range. A record will be added when there is one to add rather than an estimate to invent.
