Scapa Flow jellies
Animals firmly attached to the rock thrive on food brought to them by the currents. But there are others who use the currents in different ways - as well as a feeding ground it is a temporary home to them. Moon jellyfish often drift in swarms through the sea in summer. They've got a very mild sting, one that we can't feel. Their neutral buoyancy keeps them away from the dangers of a turbulent surface. This lion's mane jellyfish is not one to touch - it can leave painful weals, long after it's been washed up on the beach. And yet young fish seek protection among the stinging tentacles and go unharmed. Comb jellies, with their rows of swimming hairs, aren't jellyfish and don't sting. But they are voracious predators of fish larvae and even affect commercial fishing. When moon jelly swarms finally drift into trouble, there are always scavengers there to clean up. Even a jellyfish has some food value.