1 fish for non residents.
Just make sure the 1 you keep is under 18″ if you’re gonna stop and fish the US side on the way back.
I’ve fished Swell Bay (and Redgut also) in the past with good luck around the second week of July, but that is a bit of a run from Lost Bay. Looks like about 6 miles just to get to Swell bay from the campsite, over 11 to Redgut.