Ker Than, National Geographic News 2 Sep 08;
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 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.
Baker said biopsies and other nonlethal methods such as genetic and photographic identification would have been adequate for gauging the health of the whales and their food availability.
Baker called JARPA's methods of killing the whales—which included exploding harpoons and large-caliber rifles in case death was not instantaneous—"crude" and ultimately unnecessary.
Baker also questioned the biological significance of the blubber reduction reported by the Japanese team.
"This is a very small biological effect," Baker said. The change in blubber thickness was "9 percent over 18 years. That's half a percent a year."
Doubts about the scientific usefulness of the study were echoed by Stephen Palumbi, a marine ecologist at Stanford University.
"All their analysis can show is that minke whales might be getting slightly thinner," Palumbi said. "Is it biologically meaningful? It's not clear."
Palumbi called the team's hypothesis that minke whales are losing weight as a result of reduced krill in the oceans a "huge leap."
Their results show "a statistical correlation but does not reveal anything about cause," Palumbi said.
Contradictory Results
A joint statement issued by Greenpeace and the International Fund for Animal Welfare (IFAW) said the study's findings contradict previous JARPA research that suggested minke whales were benefiting from a krill surplus created by the elimination of other large whales by human hunting.
"Japan can't have it both ways," the statement reads. "The minkes can't be reaching maturity faster because they are feasting on surplus krill while at the same time losing weight."
IFAW program manager Beth Allgood expressed concern that the new study could be used to vindicate Japan's scientific whaling program at a planned meeting of the IWC later this month.
"This paper cannot be used as evidence that scientific whaling has resulted in legitimate research until the larger community reviews its methodology, statistical rigor, and whether it is ethically justifiable to kill minke whales for results like these," Allgood said.
(Read related story: "Japan May Be Ready to Deal on Whaling, Insider Hints" [March 26, 2008].)
Critics also say they are troubled by the study's suggestion that other whale species such as humpback and fin whales are outcompeting minke whales for krill.
"As far as I know, there isn't any evidence of that anywhere," Palumbi said. "If you were a conspiracy theorist, you might say this is set up to be that evidence."
Japanese researchers recently reported that humpback whales have begun encroaching upon the territories of minke whales.
The hypothesis is similar to one proposed by Japanese whale researchers in the mid-1990s that endangered blue whale populations were having trouble recovering because minke whales were outcompeting them for krill, Baker said.
"They said at the time that they needed to conduct scientific research to determine this," Baker said. "What was that scientific research? Killing minke whales."
