First off I am not saying angling closures are necessary in the circumstances. However most marine commercial traffic are under speed restrictions. Other areas have recommended reductions that many operators follow. It's claimed noise levels from that traffic is down substantially (40% to 60%).
I have been on BC Ferries a few times when the boat passed whales and they slowed down to about 5 knots. I've been on a whale watching cruise and when the boat was near whales, they shut the engine off. Most marine traffic transits through an area where whales are present. As I mentioned above fishing boats tend to loiter in the same are for extended periods. For example a couple of summers ago I counted about 3 dozen boats fishing near the south end of Mitlenatch Island.