Enjoying nature is a give-and-take deal. The critters were there first, so you have to expect that you emight get a little poop on your dock. That's not directed at you, Spoony, just a general comment to the entire thread.
And yes, beware of any otters/beavers/badgers/aardvarks or related creatures you may run across in the river arms. They very well may be part of my security network to keep you hooligans off my holes.