The indigenous(sp?) species in the Pacific Northwest is Pacifasticus Leniusculus, or the Pacific Signal Crayfish. It is the only known one to the waters as far as I found out.
They are territorial, and grow to a territory size limit, (i.e. the more crowded the area, the smaller they are. Mesachie Lake for instance has tons of them but they are relatively small.
Treat them like you would fresh water shrimp or spot prawns, although their shells are tougher they are good eating. I like to cook the tails shell on in butter and wine and garlic, leave them in the broth and crack em while slugging back a good pale ale.
Cheers