Demographic risk assessment for a harvested species threatened by climate change: polar bears in the Chukchi Sea.

Climate change threatens global biodiversity. Many species vulnerable to climate change are important to humans for nutritional, cultural, and economic reasons. Polar bears Ursus maritimus are threatened by sea-ice loss and represent a subsistence resource for Indigenous people.

Using claws to compare reproduction, stress and diet of female bearded and ringed seals in the Bering and Chukchi seas, Alaska, between 1953-1968 and 1998-2014.

Rapid climate warming is decreasing sea ice thickness, extent and duration. Marine mammals such as bearded () and ringed () seals, which use sea ice for pupping, molting and resting, may be negatively affected. Claws from bearded and ringed seals store up to 14 and 12 years of sequential analyte data, respectively.

Validation of a novel method to create temporal records of hormone concentrations from the claws of ringed and bearded seals.

Ringed () and bearded seals () inhabit vast and often remote areas in the Arctic, making it difficult to obtain long-term physiological information concerning health and reproduction. These seals are experiencing climate-driven changes in their habitat that could result in physiological stress. Chronic physiological stress can lead to immunosuppression, decreased reproduction and decreased growth.

Characterizing estrus by trans-abdominal ultrasounds, fecal estrone-3-glucuronide, and vaginal cytology in the Steller sea lion (Eumetopias jubatus).

The ability to monitor the estrus cycle in wild and captive marine species is important for identifying reproductive failures, ensuring a successful breeding program, and monitoring animal welfare. Minimally invasive sampling methods to monitor estrus in captive populations have been developed, but results suggest these tools can be species-specific in their precision and accuracy. Therefore, the minimally invasive sampling methods of trans-abdominal ultrasounds, a fecal steroid analysis (estrone-3-glucuronide, E1G), and vaginal cytology, were evaluated for their efficacy to characterize and monitor estrus in a captive breeding population of Steller sea lions (Eumetopias jubatus).

Serum estradiol and progesterone profiles during estrus, pseudopregnancy, and active gestation in Steller sea lions.

While the proximate driver behind the decline of the Western stock of Steller sea lions (Eumetopias jubatus, >80% since 1970s) is likely multifactorial, the population reduction may have been powered by a decrease in fecundity. A harvest of Steller sea lions in the 1970s and 80s revealed a 30% reduction in the proportion of pregnant females from early (October-November) to late gestation (April-May). Identification and quantification of these reproductive failures are difficult when we lack species-specific data on endocrinology associated with discrete stages of the reproductive cycle (i.