On the west coast of England (and Wales), it’s common to see lots of moon jellyfish wash up on the beach. It’s upsetting to see a dead jellyfish on the beach. But if it’s not completely dead, what should you do? Beach Stuff says that really, there’s nothing you can do, because as soon as the tide throws a jellyfish to shore, it begins to die.
Jellyfish can sense their environment due to neurons, but don’t have a brain, heart or respiratory system, so the kindest though saddest thing to do is likely to leave them. If not dead, they will likely already be dying, and you could make any suffering worse if you keep returning them to sea, for them to wash up again.
Jellyfish can still sting you (or a nosey dog) even when dead. Don’t let dogs go near jellyfish on the beach. If your dog does get stung, pull off any tentacles with a towel (don’t rub or touch them), clean area with sea water, and take dogs straight to the vet.
About the size of a plate, the moon jellyfish has four circles (gonads) through a translucent shell, they are 95% water, and will literally leave a watery footprint in the sand when they have dehydrated out of water. They catch prey using mucus and are one of the favourite food of sea turtles (which is why you should never release balloons, as turtles think they are jellyfish when they land in the sea, then eat them).
If you travel abroad, jellyfish stings can kill. Their long tentacles get wrapped around divers and swimmers, and can inject venom with stingers. Most people just get pain and red marks, but some people get very ill and a few people even die. Try not to swim near large numbers of jellyfish and wear protective clothing, like wetsuits and flippers. Serious divers can buy ‘stinger suits’ and should talk to local lifeguards about areas to avoid.