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Our objective was to identify the upper ambient temperature threshold that triggers an increase in cortisol in response to increased thermoregulatory demands in polar bears. The results reported here include endocrine data collected over two years from 25 polar bears housed in 11 accredited zoological institutions across North America. The effects of ambient temperature, sex, age group (juvenile, adult, elderly), breeding season and humidity on fecal cortisol metabolite (FCM) concentrations (N = 8439 samples) were evaluated using linear mixed models. Ambient temperatures were placed into five different categories: <5 °C, 6–10 °C, 11–15 °C, 16–20 °C, and >20 °C. Ambient temperature and humidity had a significant (p < 0.05) effect on FCM concentrations with significant (p < 0.05) interactions of sex, age and breeding season. Once biotic factors were accounted for, there was a significant (p < 0.05) increase in FCM concentrations associated with ambient temperatures above 20 °C in adult polar bears. The implications of these findings for the management of both zoo and wild polar bears are discussed.

The objectives of this study were twofold: to determine the sensitivity of gill biopsies used for the screening of Pseudodactylogyrus bini in subclinically infested American eels (Anguilla rostrata) and to evaluate the effect of bath anesthesia on the proportion of infested eels. Fifty-four eels were euthanized following either intracoelomic injection of T61 or deep anesthesia with tricaine methanesulfonate. Proportions of eels infested by P. bini diagnosed by gill biopsies taken through the gill slit and by microscopic examination of the entire gill arches were compared. The euthanasia protocol had no significant effect on parasite abundance. The prevalence of monogeneans detected by examination of nonterminal antemortem gill biopsies and by complete gill examinations was 20% and 70%, respectively. The sensitivity of gill biopsies (29%) to detect P. bini in subclinically infested eels is therefore low, and should be used for group screening rather than individual screening.

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