Capitalists when they fucking destroy nature and there's nothing left to pillage:
:shocked-pikachu:.
There's a very strong possibility at least some of the snow crab population went further north + west into colder parts of the bering sea owned by Russia / Canada.
Ganglion is kind of a misnomer when dealing with Arthropods, these are very complex structures and the Dorsal cluster is generally referred to as a brain.
There is some good evidence that the neuronal structures responsible for subjective experience (as opposed to sapience) is pretty basal and at least some Arthropods have it. Certainly my own experience keeping insects has shown they have individual likes and preferences.
I'm not vegan and I don't think overfishing of crabs is equivalent to killing "higher" vertebrates, but there does seem to be at least some moral value attached here.