This was just published last month.
In a collaborative U.S.-Russian effort in spring of 2016, 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.
In a collaborative U.S.-Russian effort in spring of 2016, 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.
Aerial survey estimates of polar bears and their tracks in the Chukchi Sea
Polar bears are of international conservation concern due to climate change but are difficult to study because of low densities and an expansive, circumpolar distribution. In a collaborative U.S.-Russian effort in spring of 2016, we used aerial surveys to detect and estimate the abundance of...
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