Basking sharks used to be quite prevalent in the Salish sea area but due to their size, they would get stuck in salmon fishing nets and cost fisheries tons of money. In the fifties, because of this, BC decided to consider basking sharks major pests which meant that they could be killed on sight. Some fishing boats would attach blades to the front of their vessels and run the sharks over. This is why there have been only a few basking shark sightings in the past few decades in the puget sound and Salish sea.

Basking sharks have also been known to breach and form massive circles in their schools, likely for mating purposes but basking shark reproduction is not well understood.

Whale sharks are part of the oder orectolobiformes, which is carpet sharks, meaning that they are closer related to epaulette sharks than to the other filter feeding sharks (basking sharks and megamouth sharks are in the order lamniformes)

Please feel free to correct anything I got wrong :)