Measuring environmental stress in East Greenland polar bears, 1892–1927 and 1988–2009: What does hair cortisol tell us?

Bechshøft, Thea; Rigét, Frank; Sonne, Christian; Letcher, Robert J.; Muir, Derek C.G.; Novak, Melinda A.; Henchey, Elizabeth; Meyer, Jerrold S.; Eulaers, Igor; Jaspers, Veerle L.B.; Eens, Marcel; Covaci, Adrian; Dietz, Runé

doi:10.1016/j.envint.2012.04.005

Cited by 68 publications

(47 citation statements)

References 91 publications

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“…Recently, several studies have provided biological validation in ursids, including grizzly bears [17], [19], polar bears ( Ursus maritimus ) [16], [18], [20], [21], and Asiatic black bears ( Ursus thibetanus ) [22]. Notably, MacBeth [23] found relatively high levels of cortisol in hair from an emaciated grizzly and an emaciated black bear ( Ursus americanus ) compared with 151 other grizzly bears.…”

Section: Introductionmentioning

confidence: 99%

Stress and Reproductive Hormones in Grizzly Bears Reflect Nutritional Benefits and Social Consequences of a Salmon Foraging Niche

et al. 2013

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Physiological indicators of social and nutritional stress can provide insight into the responses of species to changes in food availability. In coastal British Columbia, Canada, grizzly bears evolved with spawning salmon as an abundant but spatially and temporally constrained food source. Recent and dramatic declines in salmon might have negative consequences on bear health and ultimately fitness. To examine broadly the chronic endocrine effects of a salmon niche, we compared cortisol, progesterone, and testosterone levels in hair from salmon-eating bears from coastal BC (n = 75) with the levels in a reference population from interior BC lacking access to salmon (n = 42). As predicted, testosterone was higher in coastal bears of both sexes relative to interior bears, possibly reflecting higher social density on the coast mediated by salmon availability. We also investigated associations between the amount of salmon individual bears consumed (as measured by stable isotope analysis) and cortisol and testosterone in hair. Also as predicted, cortisol decreased with increasing dietary salmon and was higher after a year of low dietary salmon than after a year of high dietary salmon. These findings at two spatial scales suggest that coastal bears might experience nutritional or social stress in response to on-going salmon declines, providing novel insights into the effects of resource availability on fitness-related physiology.

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Section: Introductionmentioning

confidence: 99%

Stress and Reproductive Hormones in Grizzly Bears Reflect Nutritional Benefits and Social Consequences of a Salmon Foraging Niche

et al. 2013

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“…Lack of significant relationships may indicate the concentrations of POPs are such that they are not impacting or influencing cortisol levels. Studies on polar bear cortisol responses to POPs demonstrated a variation in relationships possibly owing to different tissue matrices (Oskam et al 2004;Bechshoft et al 2012aBechshoft et al , 2012b. For example, cortisol and PCBs measured in polar bear hair demonstrated no relationship with organochlorines (OCs) (Bechshoft et al 2012a), despite the negative trends observed between plasma cortisol and OC levels (Oskam et al 2004).…”

Section: Cortisol Associations With Biological and Biochemical Factorsmentioning

confidence: 99%

“…Studies on polar bear cortisol responses to POPs demonstrated a variation in relationships possibly owing to different tissue matrices (Oskam et al 2004;Bechshoft et al 2012aBechshoft et al , 2012b. For example, cortisol and PCBs measured in polar bear hair demonstrated no relationship with organochlorines (OCs) (Bechshoft et al 2012a), despite the negative trends observed between plasma cortisol and OC levels (Oskam et al 2004). Cortisol relationships with biochemical factors were weak and suggest a lack of relationships with the endogenous and exogenous compounds or may point to our sample set not including individuals with high contaminant concentrations or in poor condition to build extremes into the dataset for a trend to be set.…”

Section: Cortisol Associations With Biological and Biochemical Factorsmentioning

confidence: 99%

Cortisol levels in beluga whales (Delphinapterus leucas): Setting a benchmark for Marine Protected Area monitoring

Loseto¹,

Pleskach²,

Hoover³

et al. 2017

Arctic Science

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Beluga whales (Delphinapterus leucas) are facing profound changes in their habitat, with impacts expected at the individual and population level. Detecting and monitoring exposure and response to environmental stressors is necessary for beluga conservation and management of human activities. Cortisol has proven as a useful tool to assess stress on wildlife. Cortisol was measured in three blubber layers and plasma in subsistencehunted beluga whales from the summers of 2007 to 2010 using an HPLC/MS/MS. We assessed the effect of biological and biochemical factors. Cortisol ranged from undetectable to 17.8 ng/g in blubber and 2.5 to 61.2 ng/mL in plasma. Concentrations were highest in the inner blubber layer likely reflecting circulating levels. All tissues were significantly higher in 2008 for reasons that remain unclear. Cortisol levels were on par with resting levels in captive belugas. Best fit models for cortisol revealed age to be an important determinant along with length and blubber thickness. Lack of relationships with biochemical factors such as organic contaminants suggests current cortisol levels are not significantly influenced by present contaminant concentrations. Our findings support the use of middle and outer blubber tissues for an integrated measure of chronic stress that are less subject to the influence of acute stress.

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“…In addition, hair cortisol concentration (HCC) may not be as sensitive to short‐term stress (Ashley et al 2011, Gonzalez‐de‐la‐Vera et al 2011) as are other measures of hypothalamic–pituitary–adrenal activity, such as serum cortisol (Cattet et al 2003), salivary cortisol (Millspaugh et al 2002) or glucocorticoids measured in urine and feces (Hunt and Wasser 2003, Owen et al 2004). Furthermore, hair itself is a relatively stable medium, which can be collected non‐invasively or opportunistically from free‐ranging animals (Macbeth et al 2010, Bechshøft et al 2012), transported and stored at ambient temperature (Jaspers et al 2010, Macbeth et al 2010), and, under optimal conditions, cortisol incorporated into hair may remain detectable for years to centuries (Macbeth et al 2010, Webb et al 2010, Gonzalez‐de‐la‐Vera et al 2011). Recently, techniques for measuring HCC have been refined for use with hair collected from free‐ranging grizzly ( Ursus arctos ; Macbeth et al 2010) and polar bears (Bechshøft et al 2011, 2012).…”

mentioning

confidence: 99%

Evaluation of hair cortisol concentration as a biomarker of long‐term stress in free‐ranging polar bears

Macbeth¹,

Cattet²,

Obbard³

et al. 2012

Wildlife Society Bulletin

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Long-term physiological stress in individual animals may be an important mechanism linking ecological change with impaired wildlife population health. In the Southern Hudson Bay (SH) subpopulation of polar bears (Ursus maritimus), increasing stress associated with climate warming may be related to declining body condition. Accordingly, the development of tools to assess long-term stress in this species may prove invaluable for conservation efforts in this threatened population. The measurement of hair cortisol concentration (HCC) has shown promise as a potential biomarker of long-term stress in free-ranging bears. However, to serve as a useful management tool, factors influencing HCC in polar bears must be identified and then revealed to establish linkages between environmental conditions and the fitness of individual animals. We determined HCC (median ¼ 0.48 pg/mg [range ¼ 0.16-2.26 pg/mg]) in 185 polar bears captured in southern Hudson Bay from 2007 to 2009. HCC was influenced by sex, family group status, and capture period but not by body region or hair type. Using models developed through a combination of hypothesis testing and information theory, we also determined that HCC was negatively associated with growth indices (length, mass, and body condition index) linked to fitness in polar bears. Additional research will be required across several polar bear populations to establish the utility of HCC as a tool for polar bear conservation. ß 2012 The Wildlife Society.

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Measuring environmental stress in East Greenland polar bears, 1892–1927 and 1988–2009: What does hair cortisol tell us?

Cited by 68 publications

References 91 publications

Stress and Reproductive Hormones in Grizzly Bears Reflect Nutritional Benefits and Social Consequences of a Salmon Foraging Niche

Stress and Reproductive Hormones in Grizzly Bears Reflect Nutritional Benefits and Social Consequences of a Salmon Foraging Niche

Cortisol levels in beluga whales (Delphinapterus leucas): Setting a benchmark for Marine Protected Area monitoring

Evaluation of hair cortisol concentration as a biomarker of long‐term stress in free‐ranging polar bears

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