Yes, they do compete directly, but they also prey on predators of those salmon. They'll eat hake and they'll also eat salmon, so it's not clear what the overall balance would be.
We do have places like the Ballard Locks in Seattle where the pinnipeds find the salmon a lot faster than the salmon find the fish ladder, and they were able to decimate the run there. There are seals that will park at river mouths and eat smolts that are going out to sea. That's encouraged to some degree by humans, because we'll do hatchery releases that bring large numbers of smolts into a small area at the same time. We've also channelized rivers so there's a single opening instead of a wide delta.