The obvious solution is to ban ships.
Here in Pennsyltucky, deer running onto the highway is always a concern. It intensifies during the fall rut, when they REALLY go nuts. I have “deer whistles” on all my vehicles. Would a speaker below the waterline on a ship, broadcasting a known whale alarm or danger sound help alert and warn the whales? Worth a trial, I would think.
That has been proposed for areas around Boston Harbor.
I am not sure if proposed route and speed changes were
ever instituted to protect the right whales but many such
regulations were debated a few years ago.