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David @ Tokyo

Perspective from Japan on whaling and whale meat, a spot of gourmet news, and monthly updates of whale meat stockpile statistics



Antarctic blue whale increases confirmed again

A paper submitted to the IWC Scientific Committee provides further confirmation of the recovery of the Antarctic blue whale:
Sightings from the IDCR and SOWER austral summer surveys were analysed to provide abundance estimates for Antarctic (true) blue whales (Balaenoptera musculus intermedia) south of 60°S. The IDCR/SOWER ship-borne surveys have completely circled the Antarctic three times: 1978/79–1983/84 (CPI), 1985/86–1990/91 (CPII) and 1991/92–2003/04 (CPIII), covering strata totalling 64.3%, 79.5% and 99.7% of the ocean surface between the pack ice and 60°S. During the surveys, blue whales were only rarely sighted but were present around the Antarctic. Average sighting rates (schools per 1,000 km of primary search effort) were 0.24 (CPI), 0.36 (CPII) and 0.78 (CPIII). Respective circumpolar abundance estimates were 453 (CV=0.40), 559 (CV=0.47) and 2,280 (CV=0.36), with mid-years of 1980/81, 1987/88 and 1997/98. When adjusted simply for unsurveyed regions, the circumpolar rate of increase was 8.2% (95% CI 3.8–12.5%) per year, although they are still under 1% of their pre-exploitation abundance. These abundance estimates are negatively biased because they exclude some Antarctic blue whales that are north of 60°S, and because a low number of blue whales on the trackline may be missed. Additionally, estimates may include a small proportion of pygmy blue whales, probably less than 1%. Abundance estimates were also provided for each IWC Management Area and for each individual survey, but these have high associated uncertainty.
Here's a reproduction of "Figure 1" from the document, showing blue whale sightings around Antarctica:
From the paper:
Antarctic blue whales were sighted around the Antarctic, thus it is not surprising that the abundance estimates are spread among all of the IWC Management Areas. Highest historical catches were taken from Areas I–III, which have lower current abundances of Antarctic blue whales than Areas IV–VI. However, estimates are highly variable from year-to-year because of the low numbers of sightings, a feature also apparent in JARPA estimates for Areas IV and V...
Assuming this pace of recovery is maintained, Antarctic blue whale abundance will still only recover to a level of 10,000 in 20 years time. Under such a scenario, ongoing (and indeed consensus) protection seems inevitable for the next 2 decades, at least.

The paper also notes that the rate of increase (albeit with the 95% confidence interval of 3.8–12.5%) is close to the theoretical biological maximum. It's fascinating given how scarce blue whales are that they are still able to find breeding opportunities to be able to exhibit such a recovery.

It will be interesting to follow developments as hopefully a clearer picture about the Antarctic blue whale recovery emerges, and any differences in rate of increase in different parts of the Antarctic become apparent.

* * *

The paper was authored by Trevor Branch, who is a leading player in the IWC SC's Antarctic baleen whale abundance estimate work.

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Hi! David-san,

Today,the Yomiuri Shinbun gave us the nice information about the increase of humperback whales & minke whales.

Please see if you have time.


Yesterday the paper also showed
us the big topic about the whaling& whale watching. Mr,Morishita of JFA strongly insisted on the sustainable use of whales.


Sorry.the right URL is below.

Hi Y/H-san!

Yes, it's good to see the Yomiuri newspaper picking up on this news. I think for most people - Japanese or otherwise - it's simple common sense that it is quite acceptable for animals to be utilised so long as there is no risk of extinction.

Did you see the article with Mr. Morishita from the JFA in the online edition of Yomiuri, or the paper version? I did a search online, but couldn't find it.

>Did you see the article with Mr. >Morishita from the JFA in the
>online edition of Yomiuri, or
>the paper version? I did a
>search online, but couldn't find >it.

I saw it as a paper version,David-san. I wish you could have read it !(I also searched the article on web,but I could find it.)
I looked for the paper in my
room,but in vain.Alas,my old mother handed the newspaper to a paper recycle shop.

The main message of the article(of Mr.Morishita)was to show the basic position of whaling of our country.Nothing special, as usual.

On the other hand,on the same
article,Jun Hoshikawa,GPJapan,also insisted on the unnecessity of whaling in the Antarctic Ocean,while he does not reject the coastal whaling of Japan.

Obviously I find GP Japan is gradually changing their propaganda to get donations.
About two years ago,I remember they strongly repeated the stop of whalig.I know they do anything for the donation.

Totally,as far as I see, the article was neutral.


Hi Y/H-san!

Thank you for the summary of the article!

Greenpeace are very cagey about coastal whaling these days. They don't want to be criticised for their cultural intolerance on the one hand, but on the other hand they don't want to openly announce their acceptance of other whaling as that will damage their support base.

It's a good demonstration of how unprincipled Greenpeace are. Sustainable whaling is either OK and good, or it isn't.
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