Japan has been accused of falsifying data on the number and size of sperm whales killed by their commercial whaling fleets during the 1960s. Since historical data such as these are used as a baseline to assess how the animals respond to hunting pressure, the report published in Royal Society Open Science casts doubt on current population trends and demographics, as well as the validity of many studies that relied on this data. This questions our understanding of the cetaceans' current population status.
It is already known that during the 1960s, the Soviet Union (USSR) illegally killed almost 200,000 whales, but due to hunting restrictions in place at the time, it was claimed that they were in fact taking far lower numbers. This all came out in the 1990s, when Soviet biologists revealed that they’d kept secret records of the actual numbers caught, records that were then declassified. Looking through these data, it was plain to see that the nation not only killed far more whales then they reported, but ignored hunting regulations set by the International Whaling Commission (IWC) on what size of whales they were allowed to take.
The Soviet fleets were fishing sperm whales in the same region, the North Pacific, as the Japanese between 1968 and 1969. According to the researchers, by comparing the actual Soviet catch data with the numbers reported by Japan during this period, it’s plain to see that something fishy was going on. At the time, the IWC ruled that only sperm whales over 11.6 meters (38 feet) in length were permitted to be caught. While the revised USSR data showed that only 6.6% of female sperm whales caught during these years were above the legal size allowed, the Japanese fleet claimed that 97.3% of all female whales they caught were above the legal limit.
So while the Soviets were finding it difficult to find enough females of the correct size – even though they were officially reporting that everything was fine – the Japanese were reporting that they were hitting their quota each year, despite spending less time hunting and using a smaller fleet. This set alarm bells ringing. The researchers suspect that the Japanese were in fact catching two smaller whales and reporting it as one larger, throwing into doubt all population figures calculated based on this data since.
“Current population estimates and conservation depend on accurate historical data,” Phillip Clapham from National Marine Mammal Laboratory in Alaska, who co-authored the paper, told Science. “These fake data are in the IWC catch database; researchers use it. How many studies are now invalid because of this?”
And it doesn’t stop there. The scientists suspect that if they were falsifying the data on their sperm whale catches, they were probably doing the same with the number of fin and humpback whales, too. Since 1972, all whaling ships have been required to have an independent observer on board, but some still suspect that, due to the wall of silence from the Japanese about this historical fiddling of numbers, we might not even be able to trust their current whaling figures.