The common crayfish in the Russian River is the Signal Crayfish (Pacifastacus leniusculus), this is the first time I've ever seen a red swamp crawfish (Procambarus clarkii) in the river, but I know they are more common in more swampy habitats like reservoirs. Probably some, like this guy, make there way to the river from reservoirs in the summer, but I doubt they can survive the winter floods as the Signals can. Anyway thought it was noteworthy because its a first for me in a corner of the world I know very well.