Swimmer's itch is no fun at all. I know from experience. Luckily, the last several years I have avoided it in our area of Winter Harbor. It is one of the reasons many towns have made it illegal to feed ducks off public property.
Last year, we were at the cabin after a family with young children had rented. They had made friends with the ducks who would not leave us alone. My cousin took things into his own hands. (literally)
http://www.winnipesaukee.com/photopo...cat=500&page=1
(No duck was harmed, just shaken up, in the taking of this photo)