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Kristin Laidre

Principal Oceanographer

Assistant Professor, Fisheries





Department Affiliation

Polar Science Center


B.S. Zoology, University of Washington - Seattle, 1999

Ph.D. Aquatic & Fishery Sciences, University of Washington - Seattle, 2003

Kristin Laidre's Website



2000-present and while at APL-UW

An on-ice aerial survey of the Kane Basin polar bear (Ursus maritimus) subpopulation

Wiig, Ø., S.N. Atkinson, E.W. Born, S. Stapleton, T. Arnold, M. Dyck, K.L. Laidre, N.J. Lunn, and E.V. Regehr, "An on-ice aerial survey of the Kane Basin polar bear (Ursus maritimus) subpopulation," Polar Biol., EOR, doi:10.1007/s00300-021-02974-6, 2021.

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22 Nov 2021

There is an imminent need to collect information on distribution and abundance of polar bears (Ursus maritimus) to understand how they are affected by the ongoing decrease in Arctic sea ice. The Kane Basin (KB) subpopulation is a group of high-latitude polar bears that ranges between High Arctic Canada and NW Greenland around and north of the North Water polynya (NOW). We conducted a line transect distance sampling aerial survey of KB polar bears during 28 April–12 May 2014. A total of 4160 linear kilometers were flown in a helicopter over fast ice in the fjords and over offshore pack ice between 76° 50' and 80° N'. Using a mark-recapture distance sampling protocol, the estimated abundance was 190 bears (95% lognormal CI: 87–411; CV 39%). This estimate is likely negatively biased to an unknown degree because the offshore sectors of the NOW with much open water were not surveyed because of logistical and safety reasons. Our study demonstrated that aerial surveys may be a feasible method for obtaining abundance estimates for small subpopulations of polar bears.

Feeding habits of Baffin Bay polar bears Ursus maritimus: insight from stable isotopes and total mercury in hair

Stern, J.H., K.L. Laidre, E.W. Born, Ø. Wiig, C. Sonne, R. Dietz, A. Fisk, and M.A. McKinney, "Feeding habits of Baffin Bay polar bears Ursus maritimus: insight from stable isotopes and total mercury in hair," Mar. Ecol. Prog. Ser., 667, 233-244, doi:10.3354/meps13864, 2021.

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28 Oct 2021

Loss of sea ice brought on by climate change affects polar bear Ursus maritimus access to prey. Here we investigated variation in feeding habits of the Baffin Bay (BB) polar bear subpopulation in relation to sea ice, habitat use, season, and demography using hair carbon (δ13C), nitrogen δ15N), and sulfur (δ34S) stable isotope values and total mercury (THg) concentrations as ecological tracers. We analyzed hair samples from BB polar bears (n = 131) of all age and sex classes live-captured in West Greenland during the spring in 2009–2013. BB polar bears occupied a narrow isotopic space, suggesting limited variation in carbon sources and trophic position within the subpopulation. THg concentrations (median +/– SE: 5.1 +/– 0.2, range: 0.3–12.5 μg g-1 dry weight, DW were related to age class, and nearly half exceeded the suggested threshold for neurological effects in polar bears at 5.4 μg g-1 DW. Although distinct coastal and offshore space-use strategies have been reported for BB polar bears, our results suggest that both strategies lead to similar carbon sources and trophic positions. We found seasonal variation in δ13C and δ34S across both space-use strategies, with δ34S suggesting that all BB polar bears may prey on a higher proportion of benthic-feeding bearded seals Erignathus barbatus in late summer relative to spring. Despite wide fluctuations in inter-annual sea ice conditions and differences in space-use strategies among individuals, stable isotope values and THg concentrations suggested limited variation in feeding habits among BB polar bears. The variation of habitat tracers (δ13C and δ34S) was related to season, whereas trophic tracer (δ15N and THg) variation was driven by demographic group. The specialized BB polar bear diet suggests limited feeding plasticity under continued climate warming.

Accelerated sea ice loss in the Wandel Sea points to a change in the Arctic's Last Ice Area

Schweiger, A.J., M. Steele, J. Zhang, G.W.K. Moore, and K.L. Laidre, "Accelerated sea ice loss in the Wandel Sea points to a change in the Arctic's Last Ice Area," Comm. Earth Environ., 2, doi:, 2021.

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1 Jul 2021

The Arctic Ocean's Wandel Sea is the easternmost sector of the Last Ice Area, where thick, old sea ice is expected to endure longer than elsewhere. Nevertheless, in August 2020 the area experienced record-low sea ice concentration. Here we use satellite data and sea ice model experiments to determine what caused this record sea ice minimum. In our simulations there was a multi-year sea-ice thinning trend due to climate change. Natural climate variability expressed as wind-forced ice advection and subsequent melt added to this trend. In spring 2020, the Wandel Sea had a mixture of both thin and — unusual for recent years — thick ice, but this thick ice was not sufficiently widespread to prevent the summer sea ice concentration minimum. With continued thinning, more frequent low summer sea ice events are expected. We suggest that the Last Ice Area, an important refuge for ice-dependent species, is less resilient to warming than previously thought.

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In The News

How warming affects arctic sea ice, polar bears

Associated Press, Seth Borenstein, Camille Fassett, Kati Perry

Scientists and advocates point to polar bears, marked as "threatened" on the endangered species list, as the white-hot warning signal for the rest of the planet — "the canary in the cryosphere."

6 Nov 2021

Polar bears are suffering from the Arctic's loss of sea ice. So is scientists' ability to study them

Inside Climate News, David Hasemyer

The melting ice is affecting the bears’ behavior and physical condition, and it has made studying them through forays out onto the ice a treacherous business.

5 Oct 2021

In an Increasingly Noisy Arctic, Will Narwhals Fall Silent?

The New Yorker, Marguerite Holloway

The marine mammals have been observed to stop vocalizing, hunting, and feeding after hearing underwater blasts.

31 Aug 2021

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Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center