* This article is written in Japanese on August 8, 2008.
- Whales losing blubber, claims controversial Japanese study | August 26, 2008 Guardian
- Decline in energy storage in the Antarctic minke whale (Balaenoptera bonaerensis) in the Southern Ocean | Polar Biology
- The aftermath of Japanese study findings "whales losing blubber" | September 3, 2008 AFPBB News Japan (by Japanese)
First, I will show the content that the Institute of Cetacean Research (ICR) outlined in this paper published in Polar Biology.
1) A decline in blubber thickness of the Antarctic minke whale (Balaenoptera bonaerensis) in the Southern Ocean was elucidated by the Japanese Whale Research Program (JARPA).
2) It may be that the cause is a decrease in the amount of krill due to global warming.
3) The Japanese research whaling contributes also to the study of global warming.
4) It may be that the cause is a humpback whale increase, and an associated krill decrease.
5) Humpback whales may be thinly cut.
6) These findings can be provided only by lethal investigation.
After checking a list of review articles of the ICR in the past, I found one article about blubber thickness published in 2006.
This is only an inspection of the research result and should not be referred to as a theory of "humpback whales increase" and "global warming".
- Characteristics of blubber distribution and body condition indicators for Antarctic minke whales (Balaenoptera bonaerensis) | Mammal Study
IKAN (Iruka Kujira Action Network) which is the network of a Japanese citizen's group sent an open letter to the Japanese Fisheries Agency in the same year.
Although the content was to investigate an edible produce adjustment scandal of whale meat by research whaling, there is a description about the analysis of blubber thickness decrease in the answer showed by the Fisheries Agency.
The answer itself was a considerably stupid one. They said; "The amount of whale meat greatly fluctuates by investigation sea area, investigation time, and marine environmental difference including the weather of each year." But this was said of all biological parameters of research whaling, not only the amount of whale meat. So it is possible to say that research data is unreliable. About the blurring of the amount of whale meat should be attached scientific explanation originally.
They also explained; "The cause of the decline of blubber thickness is thought to be from an increase of the Antarctic minke whale or the other whale species." This means that whether the Antarctic minke whale increased or decreased (by an increase in humpback whales), either case will do for them. Whatever may be the outcome, they have nothing to lose. This is an especially self-serving explanation. The former is completely denied at the JARPA review meeting, and the later overlapped with 4) above. In the latter case, it means "the hypothesis of Antarctic minke whale = cockroach" was completely reverse, and Japanese whale scholars can offer no excuse.
But when the Fisheries Agency replied to IKAN, it should be still at a stage only of "the analysis result proved" in "Mammal Study" 2006. It may be said the hypothesis was a guess broadcast suitably announced by a person concerned with the ICR. Therefore, it was the reason Japan was criticized at the review meeting.
At the review meeting of JARPA in 2006 by the IWC Scientific Committee, it was agreed that there were no significant change of biological parameter of the Antarctic minke whale during 18 years indicating any increase or decrease trends. "The hypothesis of Antarctic minke whale = cockroach" from a bureaucrat of the Fisheries Agency was already rejected.
Since the data of blubber thickness is not directly related in the population, it might not have become a topic at the meeting. However, the whale body measurement data such as the length and the weight should have been discussed at the JARPA review. If the average weight or at every age had been reduced to a "considerable degree", it might not be wholly ignored. To this point, the first question to the hypothesis which seek to explain that a reduce amount of krill caused the blubber thickness reduction.
The amount of the decrease of blubber thickness was about 300kg during 18 years. It is 3% of 10tons of body weight and not a small amount. Since all the nutrition in the krill does not change to subcutaneous fat, the reduction in the body weight includes the other part of the body such as muscle and internal organs is more than only that of fat. This is a quite strange. Moreover, if there is a relationship between food intake and reduction, the weight data of gastric contents which are incorporated as an item in the capture survey securely must be related to equally. While the data of blubber thickness is only indirect evidence, the weight of gastric contents should be part of the data to reflect the changes in food consumption more directly.
In the summary of the paper, reduction of blubber thickness is a phenomenon independent of the other parameters. But, if a trend of the length and weight, whether increase or decrease, was not founded, the guess as mentioned above in 2) and 4) are most likely to be wrong.
Actually, there will be plenty of things to consider from the decrease of blubber thickness. For example, adaptation to rising sea temperatures is one of them. Because whales are underwater all the time, it is thought that they react sensitively to a slight water temperature. There is a high probability that since the degree of change is an annual 0.02cm with no change in body weight, the cause is demanded from global warming like the guess on 2) above.
Probably, the same tend of a change in hair weight and subcutaneous fat in order to respond to changes in the water or the air temperature should be seen in many other animals. And, in order to conclude this result as part of the environmental changes in the Antarctic, the same investigation to measure blubber thickness with other animals such as penguin and seal is necessary, the same as the Antarctic minke whale. To only to measure one species of whales is absolute nonsense.
6) is thought to be a major motivation for the ICR to use to promote this research paper. Now it is necessary to only have sight data for production of RMP (Revised Management Procedure), and the population analysis and elucidation of the ecosystem became the alternative to a biopsy. This is the current state of scientific whaling that asked "Why is lethal research needed?" and denied the paper published from many of science journals. Meanwhile, they might thought; "Blubber thickness can be know only by lethal research, and global warming is a scientific trend word now!" and expected that attention of the scientific community would change.
Some NGO claimed that there is a non-lethal alternative technique using ultrasound. For this, the argument; "To measure the blubber thickness of a living whale under water with ultrasound is not realistic" is reasonable. But, as the Guardian point out, research by harpoon damages the object and data is lost. It can be never said that the technique of making a sample damage is a good one.
Japan said; "To explore the ecology of krill widely distributed in the sea is extremely difficult, so to monitor the amount of energy storage in whales is most effective." But, this excuse is only distortion. It is more effective and rational to investigate the composition species of the Antarctic ecosystem rather than only to depend on the research whaling which needs a large amount of money and must reimburse by the commercial sale of by-products along with assistance of the government.
This study which the ICR have advertised to the media overseas about how the Japanese research whaling is scientific and useful for the study of global warming is at a very low level of importance as can be see in the contents. No conclusion is obtained at all, only this result, that the cause is either 2) or 4)? If it is complex, how much is the rate? Can any other cause be considered?
After all, the only result understood is a decline in blubber thickness of the Antarctic minke whale during the past 20 years.
If scientists formulate a general plan of research on the basis of a clear research purpose, such as "What kind of influence global warming brings the South Pole ecosystem", the priority of the present JARPA2 will proved to be very low.
The conclusion of this study is only political rather than scientific. They take up only two causes and ignore a number of other conceivable factors. One of these causes is to enhance the impression of whaling by linking it with the trend topic of global warming study, and the other competing cause is to justify the capture of humpback whales; that is the only conclusion. It is just against the idea that a scientist should be to discover the cause based on fact.