My knowledge is not as good for that part of the country.
I think we need to keep in mind that there was a long period of sealing and whaling in the Atlantic, and predators on those whales would have had their population severely depleted. If we had been having this discussion a century ago, it would have been the mammal-eating killer whales that we'd be worried about, and to deal with the seals we might have knocked them down too far and would have needed to look for other means in eastern Canada. Sharks are another seal predator, and they'll need time to recover to be efficient in dealing with seals.