Abstract
To retain viable polar bear subpopulations, scientific monitoring studies are conducted to inform adaptive management frameworks. Here we report the results of the second structured population study for polar bears in the M’Clintock Channel (MC) subpopulation. Data included biopsy samples collected during a 2014 – 16 subpopulation-wide survey, live mark-recapture data collected during the first subpopulation study from 1998 to 2000, and harvest recovery data from 1998 to 2016. Results of a closed capture-recapture model, implemented in a Bayesian framework for animals over 2 yr., produced a mean abundance estimate of 716 (95% Credible Interval = 545 – 955) for 2014 – 16, indicating an increase from the 1998 – 2000 study estimate (284; our Bayesian-calculated estimate: 325 bears). However, closed model assumptions mean our estimate represents the superpopulation. Mean litter sizes did not differ between study periods, but mean number of yearlings per adult female declined from 0.39 ± 0.10 (SE) to 0.27 ± 0.06 between 1998 – 2000 and 2014 – 16. Apparent survival estimates from observed data were biased low (0.88 ± 0.02) due to unknown immigration and emigration. However, survival calculated using the change in abundance estimates between study periods equaled 0.93, representing a population growth rate of 2%. Body condition improved between study periods. Our findings indicate the MC subpopulation recovered from overharvesting between 1979 and 1999 and may be transiently benefitting from increased biological productivity associated with local sea ice changes. Our demographic analyses were constrained by low density, low harvest, small sample sizes, low recapture probability, and lack of movement information; hence, harvest management decisions should be applied with appropriate caution.
| Original language | English |
|---|---|
| Pages (from-to) | 509-524 |
| Number of pages | 16 |
| Journal | Arctic |
| Volume | 74 |
| Issue number | 4 |
| DOIs | |
| State | Published - 2022 |
Funding
This project was logistically and financially supported by the Government of Nunavut – Department of Environment, Environment and Climate Change Canada, the Nunavut Wildlife Management Board, World Wildlife Fund – Global Arctic Programme, the Nunavut General Monitoring Program, and Polar Continental Shelf Project. We thank R. Downey, J. Goorts, and M. Harte for their hard work and dedicated field assistance. Pilots J. Barry, G. Hartery, and J. Innis kept us on track and safe. Community support was provided by the Ekaluktutiak Hunters and Trappers Association (HTA) of Cambridge Bay, the Gjoa Haven HTA, and the Spence Bay HTA of Taloyoak with local field assistance by W. Nakashook, J. Lyall (Cambridge Bay), W. Mannilaq (Taloyoak). We thank E. Richardson and D. McGeachy for the provided ice data. The project was conducted under approved Government of Nunavut wildlife research permits (2014-009, 2015-014, 2016-003), Animal Care Committee approvals of the Northwest Territories (NWTWCC 2014-003, 2015-005); and Inuit-owned land use permits (141008KTX114X002, 140120KTX114X002; 160201-KTX114X002). We thank E. Regehr, M. Taylor, and two anonymous reviewers for their expertise and constructive comments, which improved the quality of this manuscript.
| Funders | Funder number |
|---|---|
| 2014-009, 2016-003, 2015-014 | |
| 2014-003, 160201-KTX114X002, 141008KTX114X002, 2015-005, 140120KTX114X002 | |
| Government of the Northwest Territories | |
| World Wildlife Fund | |
Keywords
- Capture-mark-recapture
- Demography
- Genetic biopsy sampling
- Nunavut
- Polar bear
- Superpopulation
- Ursus maritimus
