Humans Killed Almost Three Million Whales During 20th Century


Stephen Luntz

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

1251 Humans Killed Almost Three Million Whales During 20th Century
Melissaf84 via Shutterstock. Whales breed so slowly that their numbers are taking a long time to recover.

A paper quantifying 20th century whaling has produced a figure of 2.9 million whales slaughtered, which is substantially higher than previous estimates thanks to more accurate Russian data. The research is more than just a backward look at old horrors as it provides important information about the damage done to the ocean ecosystem by the removal of such great beasts.

Humans have hunted whales for thousands of years, but for most of that time, the numbers killed were small enough that it was just a drop in the ocean. However, the invention of the steam-powered whale catcher in the 1860s changed all that. A paper in Marine Fisheries Review includes a quote from the U.S. Coast Guard in 1938 saying, “One modern factory ship can take more whales in a season than the entire American whaling fleet of 1846 which numbered over 700 vessels.”


Most of the world's whales lived south of the equator and it was only in 1905 that industrial whaling reached the southern seas. From this point, there was no looking back. The paper estimates that more than two-thirds of the whales hunted between 1900 and 1999 were in the Southern Hemisphere.

Credit: Marine Fisheries Review.

As early as the 1920s, the League of Nations called for “urgent international measures” to save whales from extinction, but the effort was as ineffective as the League's attempts to prevent World War II.

“Ultimately whaling was not a sustainable industry,” lead author Robert Rocha Jr. of the New Bedford Whaling Museum told Vocativ. "It’s a good lesson in how not to run a business.” Rocha and his co-authors tracked the number of each species of whale killed by decade as the industry shifted from blue whales to fin to humpbacks and finally minke as each previous species declined to near extinction.


Today, an estimated 10,000 blue whales survive after the killing of 150,000 in the 1930s alone. Despite the killing of minke whales being more recent, they have recovered to something like their former numbers thanks to a faster breeding cycle than larger cetaceans.

Rocha says the scale of the devastation was hidden because figures from some major whaling countries, principally the Soviet Union, were unreliable. The authors used data from the International Whaling Commission (IWC) combined with declassified reports from individual nations to produce the estimate. They note that, “New information is continually being added to the IWC database” and that these numbers exclude whales that escaped to only die of their injuries later. “When we started adding it all up, it was astonishing,” Rocha told Nature.

Whaling continues, on a much smaller scale, despite the fact that there is an oversupply of whale meat. However, whale watching now represents a far more valuable industry. We also now know that whales fertilize the ocean by eating in iron and nitrogen-rich waters and defacating where the nutrients are scarce. The massive reduction in this function has impoverished fish stocks and may have accelerated global warming.

A better understanding of the number of whales that once inhabited the oceans will help establish how much damage has been done.