Tiny fish, up to 2" long, well camouflaged against the silty substrate, maybe because they were partially clear? They swam in little schools of a couple dozen, but they were not well coordinated schools, as individuals veered off in different directions. They were very spooked by my presence.
Darker brown than the stellar sea lions and smaller with a lump on their head.
(second photo has Stellar sea lions as well)
Lighter brown than the California sea lion and larger.
The stellar sea lion is the biggest of all sea lions and has a lighter shade of fur that can look shiny in the water/light. Unlike seals the ears of the stellar sea lions have flaps that close over them.
Identification refers to jelly. See also https://www.inaturalist.org/observations/26232349 for identification of the small creatures.