Posession limits and fishing different bodies of water

[Eli]

You have to obey the rules of where you're fishing at a given time.

i.e.: It is illegal to fish for and keep sturgeon on the Ontario side of the Ottawa River. It is legal to keep one sturgeon in season on the Quebec side of the river. You'd be rightly slapped with a fine for keeping one in Quebec then crossing back into Ontario and having it in your possession while fishing the river.