On my recent walks along its banks, I've seen water snakes. I didn't see any snakes when I was a kid AFAIK. There were crayfish and *some* kinds of fish in the 1990s, but not as many as there should have been on paper. I don't know how fish populations are doing these days but I also saw a great blue heron recently, and those guys are all about eating small river fish.
further adventures in Jed York being unsuited for his position