Editor’s note: This article is part of a series on whales by island whale biologist Phil Clapham.

Anyone with a passing interest in the environment probably knows that industrial whaling is responsible for bringing many of the world’s whale species to the brink of extinction.

In the 20th century alone, some three million whales were killed, with two-thirds of those taken in the Antarctic or related areas. Many populations were reduced by as much as 99% of their pre-whaling numbers. Today, many species are recovering well, although a few populations remain dangerously vulnerable.

In 1904, a Norwegian whaler named C.F. Larsen went to the South Atlantic island of South Georgia for the first time, and was astonished at the number of whales he found. “I see them in hundreds and thousands,” he noted. The following year, he began a whaling operation there, and others quickly followed.

The vast, untouched populations of great whales at the bottom of the world were about to become the target of a slaughter that, in terms of sheer biomass, was the largest in human history.

Then, in 1925, the first stern-slip factory ship was introduced, freeing whalers from their dependence on land processing stations. Factory ships, attended by a fleet of fast catcher boats, roamed the Antarctic, piling up vast numbers of catches of every species.

By 1946, the whaling nations realized that if they didn’t attempt to impose some regulations on catches, they’d be whaling themselves out of business. They signed the International Convention for the Regulation of Whaling, which sought to impose quotas and rules, and to protect some heavily depleted species, all in an effort to whale sustainably into the future.

This reasonable idea soon gave way to a desire for more profits, and the whalers continued to ignore mounting evidence for declining populations, citing uncertainty in the numbers.

This is a common problem in resource economics: when the resource is plentiful, everyone gets into the business and invests a lot of money in expensive capital equipment (like whaling fleets). Then when the resource declines, there’s a powerful incentive to deny that anything is wrong.

Consequently, by the end of the 1950s, it was clear to scientists that whaling was unsustainable and that many populations were in serious trouble. But as it turned out, the situation was actually far worse than anyone knew.

In 1993, a prominent Russian scientist named Alexi Yablokov revealed that, beginning in 1948, the USSR had begun a huge secret campaign of illegal whaling that lasted almost 30 years. Despite being a convention signatory, the Soviets had killed everything they could get their harpoons into, including calves and supposedly protected species.

For decades, they submitted falsified whaling data to the International Whaling Commission (IWC), while keeping the true catch numbers secret.

Following Yablokov’s revelations, a group of Russian scientists worked together to publish the true catch statistics for the Soviet Antarctic whaling operations. Later, my wife Yulia Ivashchenko spent endless hours in state archives in Vladivostok to unearth the true data for the North Pacific fleets (an undertaking which has made her less than popular with the current Russian government).

Overall, she estimates that the Soviets killed more than half a million whales worldwide, of which around 180,000 were unreported.

Some of the figures are staggering. For example, the USSR reported killing 2,710 humpback whales; the true total was almost 49,000 — of which, amazingly, some 26,000 were killed in just two years. The impact of these secret catches was devastating for some populations.

The worst example is probably the right whales in the eastern North Pacific: they were almost wiped out by Soviet whaling, and today the population is believed to number only in the tens as a result.

Nor was the USSR alone in its cheating.

In 2002, a former whaling station manager revealed that Japan had been routinely falsifying catch data in its coastal operations. And some years ago, Yulia cleverly used the true Soviet catch data to demonstrate that Japan had been illegally killing large numbers of sperm whales in the North Pacific in the 1960s. The Soviets were having a very hard time finding legal-sized whales to kill, while at the same time — and sometimes in exactly the same area — Japan was blithely reporting large catches of whales above the IWC’s minimum size limit (it turned out that they’d faked both the length data and the sex of the animals taken).

Today, it’s great to see many populations bouncing back from this horrific over-exploitation. But the lesson from this shameful episode is clear: given the opportunity and the ineluctable motivation of profit, humans will invariably cheat if they can get away with it.

What happened with whales has been repeated endlessly with other natural resources, from fish to forests.

The biologist John Gulland once summarized this very well: “Fisheries management,” he said, “is [an] endless debate about the status of stocks, until all doubt is removed. And so are all the fish.”

Phil Clapham is a whale biologist who lives on Maury Island. Prior to retiring in 2019, he directed the Cetacean Assessment and Ecology Program at NOAA’s Alaska Fisheries Science Center in Seattle.