Lots of Animals and Questions at a Canada Beach

The crabs from the video are all shore crabs, most likely from the genus Hemigrapsus
The clam shell was from a Butter clam (Saxidomus gigantea) (I did not know this was their name!). These clams can hold a kind of toxin for a longer time then other clams and cannot be harvested the same way.
The little black things in the tide pool were likely a larvae of mosquito or other flying insect.
The isopod was a kind of sea Slater in the genus Ligia. They live in the damp zones between land and sea. Mostly shores and tide pools.
The purple part of the dead jellyfish was most likely the gonads; However, I am not sure it's a moon jelly.
Sources:
www.inaturalis...
wdfw.wa.gov/sp...
www.wildlifetr....