I was at Ocean Beach in SF and there were hundreds of washed up jellyfish. Should I be careful of them?

Question

I think they were Lion's Mane jellyfish. They were clear and most of then didn't have any tentacles but if they did there were few and they were small.

Answer 1

YES, you should be very careful around them. The fact that you can't see the tentacles doesn't mean they aren't in the sand. Since the tentacles are often clear, they are very hard to spot until your foot starts burning from having stepped on one. The stinging cells don't have to be attached to the jellyfish in order to sting.

The Lion's Mane jellyfish does sometimes come that far south, so your identification may be correct.

I quote:

"They have a very severe sting that can produce blisters, irritation, and muscular cramp and may even affect respiratory and heart function. Cyanea capillata  can still sting long after being stranded on the shore."

See:

http://www.marlin.ac.uk/species/Cyaneaca...