Don't get me wrong, I do not want your animals in the pond to be eaten, just don't like the idea of trapping.
You can try Humane Wildlife Control Website for ideas.
http://www.humanewildlifecontrol.com/ This company is assoicated with all of the spcas in Ontario. They are the most humane and have worked with them, quite a few times. You can also email them with your pond inquires and how to keep a coon out. that would probably be the best.