The salmon names - sockeye, coho, chum - are probably not capitalized becuase they are neither place names nor people's names, they are attempts at transliterating Aboriginal names for the fish.

I don't think "whitefish" is actually a fish, it's just a description. (DON'T QUOTE ME ON THIS!) In my part of the world, whitefish is probably cod, but it can also be haddock or any of a bunch of white [space] fish.

some more for your list:

Richardson's ground squirrel
Atlantic cod (Gadus morhua)

Oof, I had more, but I've forgotten them.