New survey estimates 10x as many polar bears in Russian section of Chukchi Sea as in USA portion

Reposted from Polar Bear Science

Posted on June 2, 2021 | 

joint US/Russian aerial survey has estimated that a minimum of 3,435 polar bears (but possibly as many as 5,444) likely inhabited the Chukchi Sea in 2016, quite a bit more than a previous study that estimated a population size of 2,937 the same year (which used data from one small US area extrapolated to the entire region).

The study, done by fixed-wing aircraft in April and May 2016 (Conn et al. 2021), estimated 3095 bears in the Russian portion of the Chukchi Sea compared to 340 in the US portion. That’s almost 10 times as many Russian bears as US bears in the Chukchi Sea, a statistic we’ve never had before now. The number estimated for the US portion in this study was almost 3 times as many as was estimated for the previous Regehr and colleagues study (340 vs. 126)(Regehr et al. 2018). Based on this latest data, the density of bears was said to be about half (~0.001 bears/km2) the density calculated from 1987 aerial survey data (0.002 bears/km2) but whether these figures are truly comparable remains to be determined.

This study required rather more models and associated assumptions than usual to come up with its population estimates. That’s primarily because they were based on sightings of only 8 bears or groups of bears in the US and 49 bears or groups of bears in Russia (‘groups’ were mothers and cubs) and surveys were limited primarily due to foggy weather and changing sea ice conditions. Small sample sizes are always problematic in this kind of research. However, because complex models and small sample sizes (only ~43 bears per year) also plagued the Regehr et al. study and that did not prevent it from being taken seriously by the polar bear conservation community (IUCN PBSG 2019), I fully expect this one to be considered a valid new population estimate for the Chukchi Sea.

While admitting that using fixed aircraft and heat-detecting technology for the first time in this count presented a number of challenges, the authors propose the method could yield better results once the kinks are sorted out.

The video of flight paths during the study (below) was provided by the authors, where the hatched area is ice:

Conn, P.B., Chernook, V.I., Moreland, E.E., Trukhanova, I.S., Regehr, E.V., Vasiliev, A.N., Wilson, R.R., Belikov, S.E. and Boveng, P.L. 2021. Aerial survey estimates of polar bears and their tracks in the Chukchi Sea. PLoS ONE 16(5): e0251130. OPEN ACCESS


IUCN Polar Bear Specialist Group Status Report 2019. Status Report on the World’s Polar Bear Subpopulations. July, 2019 (posted September 2019). pdf here.

Regehr, E.V., Hostetter, N.J., Wilson, R.R., Rode, K.D., St. Martin, M., Converse, S.J. 2018. Integrated population modeling provides the first empirical estimates of vital rates and abundance for polar bears in the Chukchi Sea. Scientific Reports 8 (1) DOI: 10.1038/s41598-018-34824-7

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Steve Case
June 3, 2021 6:12 pm

A book needs to be written with the title, “The Polar Bears are Still There”

Reply to  Steve Case
June 3, 2021 6:25 pm

….. and thriving.

Reply to  philincalifornia
June 3, 2021 6:39 pm

Along with humanity and all thanks to fossil fuels

Reply to  philincalifornia
June 3, 2021 6:44 pm

… through eating. Send your donations to World Walrus Foundation (no relation), a joint project with seals, to recognize and mitigate white polar bear carnivorous diets. Think of the [unPlanned] pups!

Izaak Walton
Reply to  philincalifornia
June 3, 2021 10:05 pm

If by thriving you mean declining by 50% then yes they are thriving.

Based on this latest data, the density of bears was said to be about half (~0.001 bears/km2) the density calculated from 1987 aerial survey data (0.002 bears/km2) “

Reply to  Izaak Walton
June 4, 2021 3:19 am

“ This study required rather more models and associated assumptions than usual to come up with its population estimates.”

So they could be and might be thriving.

Reply to  Izaak Walton
June 4, 2021 6:13 am

Then why are you wasting time here? Get out there and adopt-a-polar-bear-now!!!!!!

Reply to  beng135
June 4, 2021 8:27 am

Personally if I was a climate alarmist I’d get amongst the grants for- ‘Wot Adam and Eve done to the sharks’-
Sharks Were Almost Wiped Out 19 Million Years Ago, And They Never Recovered (
Go down a treat with the usual suspects and doomsters.

Reply to  Izaak Walton
June 4, 2021 9:05 am

As the seaice area has grown the last years, there is more place for polar bears over all, that said, the density of polar bears says nothing at all about their number.

Reply to  Krishna Gans
June 7, 2021 11:26 am

NO. The “assumed” (projected, calculated, estimated) “density” of polar bears is used to “estimate” the total number of polar bears by multiplying by the assumed area of the survey. If you start with a very bad estimate, you only get a very bad final number. But, if you “want” a low number for your political and funding and publicity and power base, you emphasize the final bad number.

Reply to  Steve Case
June 3, 2021 6:44 pm

The Polar Bears are hungry to meet Climate Scientists and Activists??

Joseph Zorzin
Reply to  Spetzer86
June 4, 2021 5:25 am

Like the guy who loved/photographed grizzlies and got eaten by one.

Crispin Pemberton-Pigott
Reply to  Spetzer86
June 4, 2021 1:12 pm

I think the word is “hungering”.
And you are correct.

Dave Fair
June 3, 2021 6:54 pm

Billions for CliSciFi computer games, but not enough for a decent aerial survey of Polar Bears. Must be that the bears are no longer useful for their Marxist propaganda.

Bruce Ranta
Reply to  Dave Fair
June 3, 2021 7:01 pm

There has seldom been adequate $ for field studies. There was back in the 1960’s, but ever since, less and less. Lots of $ for model schmodel, though….

June 3, 2021 6:59 pm

Stop falling for the leftist misdirections and stop talking about pollar bears , you cannot win this debate by counting bears.

Jan de Jong
Reply to  Eben
June 4, 2021 1:02 am


June 3, 2021 9:03 pm

There’s a simple explanation. When the bears wander into U.S. territory, they wind up with a hangover, a purple tattoo on their hip, wondering where the heck they are, and where the $#@! collar came from.

The Russians leave ’em alone.

So they learn where NOT to go.

Craig from Oz
June 3, 2021 9:39 pm

Can we be sure these are not Russian Bot-Bears? 😀

Reply to  Craig from Oz
June 3, 2021 9:50 pm

Yeah because they’re straight out of a Bundy Rum ad.

June 3, 2021 9:50 pm

It’s a polar bear gap! The US needs to increase its output of polar bears to meet this new Russian threat.

Reply to  RoHa
June 4, 2021 2:57 am

LOL! Yeah, all we give ’em is Coke®**. The Russians give ’em vodka. The 10:1 results are no surprise.

The U.S. gets the teetotaler bears. The Russians get the party animals.
**It’s true. I saw it on TV.

June 4, 2021 3:02 am

So they did not actually count bears they played with computers and drank overpriced coffee. Got it.

June 4, 2021 5:37 am

The Russian Arctic is “all” of the Arctic according to Putin and he intends to build up his military there next.

Richard Page
Reply to  ResourceGuy
June 4, 2021 12:04 pm

Next? He’s been increasing the Russian military in the Arctic over the last 10-15 years at least. Early 2000’s saw Russian warships regularly patrol the area for the first time in about 20 odd years and the military bases on the islands and mainland are being reactivated and rearmed. While the US and EU were wetting their panties wondering what Putin would do about Ukraine and Eastern Europe, Putin was consolidating his grip on the Arctic.

June 4, 2021 7:47 am

Joey “Ice Cream” Biden sez those Russian bears can walk right into the US ….no problemo…if they promise to mail in vote demrat.

June 4, 2021 9:54 am

Logistically speaking, the obvious means of getting an accurate count of polar bears in the arctic would be to use LEO sats with sensitive IR. The bears are all going to look like little but very bright lights on the ice surface. Best done at night for max. IR sensitivity.

The only way to miss any bears would be those that might be diving under the ice at the moment the sats fly over.

A single mini sat, or a very small constellation of them, could continuously track all polar bears, day or night, all year around. No need for LIDAR as there is no vegetation to mask a bear. Even if a bear is inside a den within the ice, the opening to the den would still show up on IR.

Reply to  Duane
June 4, 2021 9:55 am

The sat method would of course be unaffected by fog or clouds.

Randle Dewees
Reply to  Duane
June 4, 2021 7:22 pm

A bear from LEO? I don’t think so, at least not by IR signature. Just going on gut here but that’s not much of a source for 100 plus miles slant path. For a “small sat” optical system each pixel will cover hundreds or thousands of square meters. Look at Sat IR maps of fires, the circle representing pixel coverage is huge. Anyway, check your assertion with a radiometric calc. It will be fun and hey, maybe it can work.

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