Holy cow, this much be heart breaking. Your real only option is get someone with a wetsuit. I bet somewhere there is a diver near you that would help you. Maybe visit some divers pages in WI.

Another option possibly is to fashion you own oyaster tongs out of yard rakes Might have to be creative.

But, I know your probably temped just to jump in after it and be out quick. But man it ain't worth it.