California birders use cruise ships in spring as they try for offshore petrels during repositioning runs. Holland America, Princess Cruises, and others need to move boats from Mexico to Alaska as they go from winter routes to summer routes, and birders go one-way from L.A. to Vancouver, using spotting scopes on the stable decks to ID pelagic birds.
See for example WINGS tours, for guided excursions on these routes.
I am passing on a report from one of these trips. The leaders say they had
“11 cetacean species including very close Sperm, Sei, and Bairds Beaked whales. Northern right whale dolphins put on a show as well.”
These trips supposedly are good for non-listing spouses, since it’s a regular cruise otherwise.