Have you ever wondered how scientists count whales and how accurate their population estimates are?
The June issue of ‘Significance’ a journal focused on statistics has an article by Philip Hammond, a former Chairman of the Scientific Committee of the International Whaling Committee (IWC), explaining some of the techniques for estimating population numbers and it includes comment that:
“The minke whale is the most abundant species of baleen whale, with a world population of hundreds of thousands, maybe as much as a million. In recent years most whales killed for commercial purposes have been minkes. In the North Atlantic about 600 a year have been taken by Norway under objection to the moratorium and about 30 to 40 by Iceland under special permit. Japan annually takes about 450 minke whales in the Southern Ocean and about 150 in the North Pacific under special permit. These catches are small relative to the estimated numbers of whales and are unlikely to have an adverse impact on populations.
The number of blue whales in the world, however, is only a few thousand. In the Southern Ocean an estimated 400 to 1400 remain from a population that probably once numbered about 750 000. Blue whales have been protected since the 1960s but they have very low rates of increase and it will be a long time before we know whether or not they will recover from the devastating exploitation of the 20th century.”
So what is limiting the recovery of blue whale numbers?
I’ve been told that minke whales compete with blue whales and that high minke whale population numbers could be impacting on the recovery of blue whales?[1] If this is the case, could harvesting of minke whales by the Japanese in the Antarctic help recovery of the depressed blue whale population?
After posting this note, I received an email from a reader with comment that: If blue whales are failing to recover it may be because of the various problems associated with small population size. …The contention that Blue Whale recovery in the Antarctic is being inhibited by prey competition from Minke Whales has little basis in existing data. …although the Blue Whale’s dependence upon a single food source (krill) is somewhat offset by the latter’s great abundance, this stenophagy would make the species more vulnerable in the event of a major decline in prey. [2]
Ann Novek recently sent me a note explaining that: “There are no direct actions against Norwegian whaling anymore from Greenpeace’s side, the new tactic is dialogue. Norwegian whaling has silenced a lot since the turbulent 90’s.”[3]
According to Norwegian Greenpeace activist Truls Gulowsen speaking three years ago, last year’s a quota of 600 minke whales posed no threat to minke whales in the north east Atlantic. He has also suggested that campaigns against whaling can distract from the real threats to the coast, including overfishing and the risk of oil industry pollution.
What are the most significant threats to the world’s whales? Which whale species really need ‘saving’ and how can they be best ‘saved’?
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[1] I’ve not seen the supporting studies/literature. If you have links/references please post as a comment or send to jennifermarohasy@jennifermarohasy.com
[2] From Clapham, P.J., Young, S.B. & Brownell, R.L. Jr. 1999. Baleen whales: conservation issues and the status of the most endangered populations. Mammal Review 29: 35-60. http://whale.wheelock.edu/archives/ask01/att-0020/01-blue.rtf
[3] Thanks to Ann for sending the note with information and links including: ‘Norway’s Disputed Whaling Season Opens’ Monday April 18, 2005, By DOUG MELLGREN, Associated Press Writer, OSLO, Norway, &
‘Redde verdenshavene’ (Save the Oceans) and ‘Hvalfangst’ ( Whaling) at http://www.greenpeace.org/norway/campaigns/hav/hvalfangst (Only in Norwegian), & Truls Gulowsen’s statement “that a quota of 600 minke whales poses no threat to the minke whale population” from the magasine Folkevett at
http://www.folkevett.no/index.php?back=1&artikkelid=1079 ( only in Norwegian).
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Hi Jennifer,
I see that you have changed my guest blog post a bit…Greenpeace’s spokesman Truls Gulowsen made the comment ” a quota of 600 Minke whales poses no threat to the Minke whale population” for three years ago in the Norwegian magasine Folkevett. You statet it was made regarding last year’s quota in the AP press release in 2005, that is not the case.
Greenpeace Norway is very dissatisfied that quotas have been increased in Norawy, and GP spokesman Truls Gulowsen made the statement ” that increased whaling is no solution to coastal Norway’s problems”(2005)
They also believe that increased quotas are provocative to the world community( 2006)
” high minke whale population numbers could be impacting on the recovery of blue whales”.
This is a statement made by the Japanese and Icelandic Government. It is pure nonsense, only a bad excuse to justify whaling. It’s the same nonsense as ” the whales eat too many fish”.
Blue whales and Minkes have lived together in complete harmony in the ecosystem for millions of years.
According to Greenpeace Norway major threats to the whales are 1) Climate change 2) Marine pollution
Hi Ann,
Sorry about the date/year mixup. I’ve now correct it in the main text … changing it from last year to three years ago.
The comment about minke whales impacting on blue whales numbers has been made by a few Australians.
A fellow at at Darwin univeristy involved with CITES suggested this to me and I am pretty sure that well know Australian Tim Flannery made the comment publicly some years ago – but I can’t find a link/reference?
Hi Jennifer,
Thanks for the correction and information. Anyway the Fisheries Ministry of Iceland made the same comment in 2003.
It seems like the blue whale population is increasing:
http://www.marineconnection.org/news/general/blue_whale_pop_increasing.htm
Jennifer wrote
“What are the most significant threats to the world’s whales? Which whale species really need ‘saving’ and how can they be best ‘saved'”
Off the top of my head, pollution, boat strikes, unregulated whale watching, habitat degradation ( pollution – physical and acoustic ) Modern day Whaling in reality is a drop in the ocean compared to those…
What species really need saving? Northern right whales for a start, various dolphin species.
How best to ” save them “? Well, giving your money to an NGO is a waste of time – that much I do know ;p
In reality, there is not much than can be done to ” save ” northern right whales from becoming extinct within the next few hundred years – the population is simply too small and the real threats they face are ship strikes, entanglement and pollution
There is a recovery plan ( PDF here ) http://www.nmfs.noaa.gov/pr/pdfs/recovery/whale_right_northatlantic.pdf ( 137 pages )
Jennifer, George,
Even more endangered than the Northern right whale is the Western Gray whale. Population between 70-100 individuals. It’s scary that Shell, Mitshubishi and Mitsu are involved in projects constructing off-shore platforms and undersea pipelines located amidst the whales’ only feeding grounds.
The project is the controversial Sahkalin II oil and gas project at Sahkalin Island in the Russian Far East.
The population of harbour porpoises in the Baltic Sea is also endangered mainly due to entanglements in drift-nets( for cod and salmon).
Regarding the statement that a huge population of Minkes could suppress the blue whale population, I received that information twice from the Ministry of Fisheries in Iceland. I have unfortunately deleted the e-mails but I recall that they mentioned that the minkes could take over blue whale’s nisches in the ecosystem(?).
Ann,
The confirmation of steady increase in Blue whale numbers is welcome news, and it’s interesting to note that it was only possible amongst other reasons because of the research ship provided by the Government of Japan.
In fact recent IWC Scientific Committee reports note that the estimated rate of increase is around 7% a year, although the estimated abundance is still very low, so the net increase in numbers is far less than what is seen for humpbacks.
> It is pure nonsense, only a bad excuse to justify whaling.
How is it that you are able to rule out such a possibility?
Aren’t you just saying that it is nonsense because you don’t want to see any whales killed, even if it potentially serves a conservation benefit?
> Blue whales and Minkes have lived together in complete harmony in the ecosystem for millions of years.
Of course, humans joined the party in the early 1900’s and reduced Antarctic blue whale numbers drastically, which is noted as one of the reasons for the increase in minke whale abundance that is believed to have occured since that time.
If humans are capable of screwing up completely and unbalancing the scales, isn’t it possible that we have the ability to rebalance the scales again through different actions?
Over time the ecosystem may find it’s way back to an equilibrium again, but it’s important and realistic to recognise that today humans are part of the ecosystem, and as such I personally see nothing wrong with the notion of trying to pro-actively encourage positive conservation outcomes, rather than sit around complaining and whinging at those who do.
It’s my view that we are capable of acheiving our goals. Humankind did not send men to the moon and back purely with good luck.
There is an article by Seiji Ohsumi of the ICR on the hypothesis of competition between baleen whales in the Antarctic here:
http://luna.pos.to/whale/jwa_v10_oh.html
I’m looking forward to see Ann punch holes through it.
(by the way – hi all – back from my summer holiday :-))
Hi David,
Welcome back – we have another discussion back at “Whaling – pro and con” as well!
Don’t you think that we are talking about gross oversimplifications of basic ecological theories here?
I received the following comment and useful links from a reader and have added some of this information and information at the link into the above blog post:
Here´s a reference from Phil clapham a few years back : http://whale.wheelock.edu/archives/ask01/att-0020/01-blue.rtf
In particular:
The contention that Blue Whale recovery in the Antarctic is being inhibited by prey competition from Minke Whales (e.g. IWC, 1994, p. 102) has little basis in existing data (Clapham & Brownell, 1996). Finally, although the Blue Whales dependence upon a single food source (krill) is somewhat offset by the latters great abundance, this stenophagy would make the species more vulnerable in the event of a major decline in prey. Human overexploitation of Antarctic krill stocks, or declines due to global climatic changes (Loeb et al., 1997) could precipitate such a problem, but at least the former does not appear likely in the foreseeable future. A Recovery Plan for the Blue Whale in U.S. waters has been produced by the U.S. National Marine Fisheries Service (Reeves et al., 1998).
And another here:
http://www.blackwell-synergy.com/doi/abs/10.1046/j.1365-2907.1999.00035.x?journalCode=mam .
Blue whales only feed on the very largest schools of krill and it is entirely foreseeable that an increased population of smaller Minkes would be capable of fragmenting krill schools to make them less viable for exploitation by Blue Whales.
Attention also needs to be focussed on the role of the expanded Crab Eater Seal population which does not migrate a long way north in winter and consequently, feeds on Krill stocks before the Krill is as mature as it is when whales return.
Because both whale species migrate north in winter, they allow the Krill to grow before they commence feeding on them. But a KG worth of juvenile Krill eaten by a seal or penguin will amount to 4 or 5 kg less food for whales.
And there seems little room for doubt that the claimed 750,000 population of Blue Whales is an overstatement based on whaling records that fail to adjust for the increased survival of juveniles due to predation of adults.
It is also apparent that the Blues had more than a century to exploit the niche left by hunting of other Baleen species in the 18th and 19th Centuries. So even if there was a stable population of Blues when hunting of them started, it was most certainly a population in ecological profit. That is their population had expanded beyond natural equilibrium levels.
Meanwhile some scientists are talking about competition between Minkes and Blue whales, their main feed in the Southern Oceans is krill.
What is alarming IMO is that both New Zealand and especially Norway are going to expand Krill fishing in the Antarctica. Norwegian fishermen made a fortune on Krill fishing in the Antarctic some months ago.
Read my short post on this here:
http://ctk.greenpeace.org/discussions/message-view?message%5fid=2110382#
The IWC and CCAMLR are apparently working to set up cooperative efforts between the two bodies.
This is good in terms of conservation of commercial valuable species.
I was surprised by the 750,000 figure for Blue whales too. I’ve seen estimates of around 200,000 for blues and 400,000 for fins. I wonder where current (official) IWC pre-whaling estimates might be found.
750,000 Blue whales is one hell of a lot of biomass.
Hi David,
Some people have no shame at all… First they drive the blue whale population near extinction and then they blame the minkes for suppressing their recovery…
Don’t you think it is a bit strange that only scientists from the prowhaling camp share this view?
It’s amazing what their imagination can work out!
> First they drive the blue whale population
> near extinction and
Out of interest, have you ever collated statistics to see companies from which nations were responsible for the depletion of blue whales and to what degree?
> then they blame the minkes for suppressing their recovery…
This is not an issue of “blaming” minkes. It’s just a matter of aiming for the optimal outcome. Once the Blue whales recover to an abundant level, Japan will (going by current trends) want to hunt them again too, as well as the minke and other abundant species.
> collated statistics
Just had a look at this now, based on Blue whale catch figures by factory ships since the 1931/32 season:
Norway 41%
British Commonwealth 35%
Japan 13%
+ Others
David,
I’m well aware that Japan was not the only nation involved in this dirty business, you have already mentioned other nations as well, the USSR, the UK, Germany, Norway…as a matter of fact I would be pleased if you have some link to this statistics.
Unfortunately, I’m very pessimistic regarding the recovery of the Blue whales, IMO irreparable damage might have happened to this population… can you tell me why the Newfoundland cod population never has recovered despite an over decade old moratorium?
Ann,
Lots of whaling statistics here (based off official IWC figures as far as I can see)
http://luna.pos.to/whale/sta.html
Recent news seems to me to provide lots of hope for the recovery of the Blue whale. 7% growth is a figure that I’ve seen several times now. This is seemingly a trend in increased abundance that has been observed.
Of course, if we really care about conserving blue whales, even if that means reducing the size of the minke population (? whether this is required), we should be prepared to look at such options. There are people willing to eat minke whales, after all, and if it helps speed up the blue whale recovery even a little bit more I personally am happy to put up my hand and contribute further. But then I have no aversion to killing whales sustainably for food.
> can you tell me why the Newfoundland cod population never has recovered despite an over decade old moratorium?
Not familiar with it.
By the way, another article you may be interested in:
http://luna.pos.to/whale/jwa_v10_best.html
“The apparent ability of this species to stage a recovery from such a low level would seem to be a good omen for what must now be considered the most threatened of all the southern whales, the Antarctic blue whale.”
(Peter Best is a South African scientist).
Interesting Stats David,
It´s also interesting to see who actually owned large parts of various whaling fleets, especially in relatively modern times ( 40´s 50´s 60´s )
Onassis for example, was one particular well known owner
David,George,
Thanks for the information… much we aren’t aware of, Onassis grandchild , who inherited all the Onassis fortune, has a Swedish stepmother and spends summers in Sweden…
‘It´s also interesting to see who actually owned large parts of various whaling fleets, especially in relatively modern times ( 40´s 50´s 60´s )
Onassis for example, was one particular well known owner.’
The Onassis fleet was sold to the Japanese.
I wrote previously that Norway has big plans to expand the krill fisheries in the Antarctic.
So why are they fishing for krill?
It seems like they are making oil of krill that is sold for
US$200 per liter.
The krill industry is estimated to have a value of many billion Norwegian kroner.
http://www.fiskaren.no/incoming/article107309.ece
Krill oil is probably meant for fish farming
> The Onassis fleet was sold to the Japanese.
As were many western owned fleets.
I think Japan was hacked off that nations who sold their fleets to them then campaigned for a moratorium on commercial whaling.
> The Onassis fleet was sold to the Japanese.
Unike his private yacht with the Sperm whale willy bar stools …. strange but true
Hi my name is sammy
and i would like to know if all whales eat krill and why
thankyou
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