Whale oil was a huge industry much more recently; it kept on chugging along into the 1880s. And whale hunting for baleen remained a major industry into the beginning of the 20th century. And the soviets and the japanese and the norwegians continued hunting whales throughout the 20th century. For whales like the Right Whale, there were several hundred thousand whales in the global population and now there are a few thousand throughout the planet. Whale populations are nowhere near recovered; this is due mostly to hunting, but partially this is also because industrialized fishing has destroyed their food sources, the use of sonar has hurt their underwater communications, and their habitats have been degraded by development and terraforming. Whales also reproduce rather slowly, so it will take some time for them to recover.

Source: The World Hunt by John F. Richards