Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada

Galicia, Melissa P.; Thiemann, Gregory W.; Dyck, Markus; Ferguson, Steven H.

doi:10.1016/j.ecolind.2021.108245

Cited by 5 publications

(7 citation statements)

References 87 publications

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“…It is also possible that the high proportions of beluga/narwhal indicate that the energy density of the diet decreased during this year (Rode et al, 2022). A high proportion of beluga whales, similar to this study's estimate in 2009, was estimated by QFASA in previous studies of BB polar bears (Galicia et al, 2015, 2021; Thiemann et al, 2008), as well as in other subpopulations (Florko et al, 2021; Galicia et al, 2021).…”

Section: Discussionsupporting

confidence: 89%

“…Prey library differences may have also contributed to differences between the studies. Both Galicia et al (2015) and Thiemann et al (2008) included harbor seals as potential prey items, whereas Galicia et al (2021) excluded harbor seals from the BB prey library. QFASA‐generated diet estimates in the present study showed large individual variability within each demographic group (see Table 1); this variability suggests other factors, such as space‐use strategy, may be driving dietary differences within groups.…”

Section: Discussionmentioning

confidence: 99%

“…The subsequent prey library included previously published values for 45 bearded seals ( Erignathus barbatus ; Davis Strait; collected from 1997 to 2003; Thiemann et al, 2008), 22 belugas ( Delphinapterus leucas ; Davis Strait, Lancaster Sound; collected from 2000 to 2001; Thiemann et al, 2008), 13 narwhals ( Monodon monoceros ; BB, Lancaster Sound; collected from 1999 to 2001; Thiemann et al, 2008), and 9 ringed seals ( Pusa hispida ; Lancaster Sound; collected in 2018; Facciola et al, 2022), with 16 harp and hooded seals ( Pagophilus groenlandicus and Cystophora cristata ; East Greenland; collected in 2018; Land‐Miller et al, 2024). Harbor seals ( Phoca vitulina ) were excluded as a potential prey item due to their low abundance in Greenland (Rosing‐Asvid, 2010); harbor seals were also excluded as a prey item in a recent study on BB polar bears (Galicia et al, 2021).…”

Section: Methodsmentioning

confidence: 99%

“…We further refined the prey library by conducting a leave-one-prey-out (LOPO) analysis with the diagnostic function lopo in the qfasar package to cross-validate the prey library (Bromaghin, 2017). The subsequent prey library included previously Harbor seals (Phoca vitulina) were excluded as a potential prey item due to their low abundance in Greenland (Rosing-Asvid, 2010); harbor seals were also excluded as a prey item in a recent study on BB polar bears (Galicia et al, 2021).…”

Section: Qfasa Diet Modelingmentioning

confidence: 99%

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Space‐use strategies drive diet composition of Baffin Bay polar bears

Stern,

Laidre,

Born

et al. 2024

Ecosphere

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Polar bears (Ursus maritimus) depend on sea ice to hunt their ice‐associated prey. However, climate‐induced sea ice loss is leading to changes in space‐use strategies of polar bears, with bears in some subpopulations spending more time on land or selecting alternative habitats. One such documented alternative habitat is glacier ice, which provides year‐round access to prey, although the feeding habits of polar bears using glacier ice relative to those following the retreating ice and/or seasonally moving onshore are not known. Here, we use adipose tissue from polar bears (n = 104) from the Baffin Bay subpopulation live‐captured in Northwest Greenland during the springs of 2009–2013 to investigate dietary patterns between space‐use strategies inferred from satellite telemetry data, while considering demographic and interannual variation. Using quantitative fatty acid signature analysis (QFASA) to generate diet estimates, ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus) were estimated as the primary and secondary prey of Baffin Bay polar bears for all sex/age classes and sampling years, apart from a single anomalous year (2009) with a relatively high proportion of beluga (Delphinapterus leucas) and narwhal (Monodon monoceros). While demographic and short‐term temporal variation was minimal, fatty acid signatures and QFASA‐generated diet estimates clearly differed between polar bears using coastal and offshore space‐use strategies. “Offshore” adult females (n = 31), which make long‐distance movements across the Baffin Bay pack ice, had high proportions of C22‐chain length monosaturated fatty acids and diet estimates that included beluga, narwhal, harp (Pagophilus groenlandicus), and hooded seal (Cystophora cristata). “Coastal” adult females (n = 6), which remain resident at glacier fronts in Northwest Greenland year‐round including during the sea ice‐free season, consumed proportionally more ringed seals (+13%) and similar proportions of bearded seal, but essentially no beluga and narwhal or harp and hooded seal. Thus, space‐use strategy is a driver of intrapopulation diet variability. As space‐use strategies change with ongoing loss of sea ice habitat, our results suggest important ramifications for polar bear feeding patterns.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Qfasa Diet Modelingmentioning

confidence: 99%

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Space‐use strategies drive diet composition of Baffin Bay polar bears

Stern,

Laidre,

Born

et al. 2024

Ecosphere

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“…As a result, the diet of polar bears in different regions changed. In Nunavut, Canada, the diet of polar bears is varies regionally [10]. The ringed seal is still the primary food but the highest levels of walrus hunting was found in a specific region with a specific population of bears [10].…”

Section: Case Studymentioning

confidence: 99%

The impact of global warming on polar bears' diet and habitat

Jiao,

Qiu,

Yang

2023

TNS

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Conventional fuels produce large amounts of greenhouse gases leading to global warming and with it dramatic changes in the Arctic, especially for its top predator, the polar bear. The environment of polar bears will gradually be more affected and challenged. This literature review explores how climate change has impacted the diets and reproduction of polar bears, along with potential solutions to mitigate these effects. The loss of sea ice due to rising temperatures has led to a decline in the number of primary prey, forcing polar bears to hunt alternative prey, including reindeer, to survive. Furthermore, reduced sea ice is affecting the reproduction and survival of the polar bear population, with the decline in genetic diversity posing a threat to their long-term survival. To mitigate these effects, reducing greenhouse gas emissions, protecting critical polar bear habitats, restoring and managing their habitats, and international collaboration and legal interventions are necessary. The implementation of these solutions will help to ensure the continued existence and thriving of this magnificent animal in the Arctic ecosystem.

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Non-invasive biomonitoring of polar bear feces can be used to estimate concentrations of metals of concern in traditional food

Eccles,

Boutet,

Branigan

et al. 2024

PLoS ONE

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The Arctic faces increasing exposure to environmental chemicals such as metals, posing health risks to humans and wildlife. Biomonitoring of polar bears (Ursus maritimus) can be used to quantify chemicals in the environment and in traditional foods consumed by the Inuit. However, typically, these samples are collected through invasive or terminal methods. The biomonitoring of feces could be a useful alternative to the current metal monitoring method within the Arctic. Here, we aim to 1) quantify the relationship between concentrations of metals in the feces and tissues (muscle, liver, and fat) of polar bears using predictive modeling, 2) develop an easy-to-use conversion tool for use in community-based monitoring programs to non-invasively estimate contaminant concentrations in polar bears tissues and 3) demonstrate the application of these models by examining potential exposure risk for humans from consumption of polar bear muscle. Fecal, muscle, liver, and fat samples were harvested from 49 polar bears through a community-based monitoring program. The samples were analyzed for 32 metals. Exploratory analysis indicated that mean metal concentrations generally did not vary by age or sex, and many of the metals measured in feces were positively correlated with the internal tissue concentration. We developed predictive linear regression models between internal (muscle, liver, fat) and external (feces) metal concentrations and further explored the mercury and methylmercury relationships for utility risk screening. Using the cross-validated regression coefficients, we developed a conversion tool that contributes to the One Health approach by understanding the interrelated health of humans, wildlife, and the environment in the Arctic. The findings support using feces as a biomonitoring tool for assessing contaminants in polar bears. Further research is needed to validate the developed models for other regions in the Arctic and assess the impact of environmental weathering on fecal metal concentrations.

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Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada

Cited by 5 publications

References 87 publications

Space‐use strategies drive diet composition of Baffin Bay polar bears

Space‐use strategies drive diet composition of Baffin Bay polar bears

The impact of global warming on polar bears' diet and habitat

Non-invasive biomonitoring of polar bear feces can be used to estimate concentrations of metals of concern in traditional food

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