I was talking with a friend about lake pontchartrain, and he claims him and some other people go way out in the middle of the lake and shoot skeet off their boat. He may be full of crap, but that does sound like a ton of fun. Are there any laws or rules that would prohibit this? Maybe if you're able to retain all your shells so your not littering.
For your legal query: There are 6 Parishes that crisscross Lake Pontchartrain. A sizeable one of which is Orleans. There is no legal discharging of firearms in ANY part of Orleans Parish. Littering, as you alluded to, is an offense in ALL.