for National Geographic News
A new study by Japan's national whale-research program is drawing sharp rebuke from scientists and conservationists who say the results did not necessitate killing more than 4,000 whales.
Critics have long accused Japan of using its scientific whaling program to circumvent a 1986 moratorium on commercial whaling by the International Whaling Commission (IWC).
In the new research, Kenji Konishi of Japan's Institute of Cetacean Research and his colleagues analyzed data from 4,704 Antarctic minke whales killed by the Japanese Whale Research Program (JARPA) from 1987 to 2005.
They concluded that the thickness of the whales' blubber decreased by 3.6 millimeters (0.14 inch), or about 9 percent, during the 18-year period.
The Japanese team suggests the thinning blubber may be due to either global warming-related reductions in ocean krill populations, competition by other whale species, or a combination of the two factors.
The minke whales killed by JARPA were preserved for study or openly sold as meat on the Japanese market, as is allowed under IWC regulations.
The study is detailed online in a recent edition of the journal Polar Biology.
"Crude" and Unnecessary
Konishi said killing the whales was the only way to ensure the measurements of the blubber's thickness were consistent across the different specimens.
"These data could only be obtained using lethal research," Konishi told National Geographic News.
Previous studies using biopsy samples, which are taken from living whales, have not obtained "total fat contents and thus energy content" of the animals' blubber, Konishi added.
Scott Baker, associate director of the Marine Mammal Institute at Oregon State University, was not involved in the study.
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