Every now and then these pelagic crabs wash into the bay and up on some of the beaches. Pleuroncodes planipes, sometimes called the pelagic red crab (or simply "red crab"), tuna crab or langostilla, is a species of squat lobster from the eastern Pacific Ocean.
It is usually found only south-west of San Diego but in warmer years, its range may extend northwards into California. This is usually indicative of an El Niño event. Large numbers occasionally wash up on beaches] possibly after the animals have been swarming in order to mate. The southern limit of the species' range is in Chile.
It is also called a tuna crab But sea otters and gray whales love them as well as all the gulls. The internet called them small crab look alike. To me they look like red crayfish a lot.
I am surprised that it is not considered a good thing by the fisherman because it means the waters are warmer. But that might be the answer to why the sea lions and harbor seals are having such a tough time getting enough food. Time will tell as we keep butting up against pupping season.