In the mid-70s, the United States passed the Marine Mammal Protection Act, because the numbers of whales were declining all around the world. Whales were routinely hunted for food, for whale oil, for sport, and scientists were afraid they were going extinct. As time passed, a whale watching industry developed. The New York Times reports on human-whale interactions in this article:
Watching Whales Watching Us.

A small excerpt from the article:
“I read before my journey to Baja of what happens to people when they come in contact with a whale, how they tend to go, literally and figuratively, a bit overboard: nearly tipping over boats for a passing touch; spontaneously breaking into song; crying out in ecstasy; or just flat-out crying.”

Whales are enormous animals; their sheer size can be startling. When I was scuba-diving some years ago and we were lucky enough to encounter a juvenile humpback whale, it took me several moments before I could be sure what I was seeing. A thirty foot animal, especially one that is watching you as carefully as you are watching it, is huge and scary–and fascinating. The memory seared itself into my brain, and I can still see that young whale anytime I want, just by closing my eyes and remembering.