Long-term, Harvest-based Monitoring of Ringed Seal Body Condition and Reproduction in Canada’s Western Arctic: An Update through 2019 + Supplementary Appendix 1 (See Article Tools)

• Published in: ARCTIC
• Main Authors: Harwood, Lois A., Smith, Thomas G., Alikamik, John, Alikamik, Emma, Lea, Ellen V., Stirling, Ian, Wright, Harold, Melling, Humfrey, Zhu, Xinhua
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: The Arctic Institute of North America 2020
• Subjects: Arctic; Prince Albert Sound; Amundsen Gulf; Pusa hispida; ringed seal; Sea ice
• Online Access: http://dx.doi.org/10.14430/arctic70428; https://journalhosting.ucalgary.ca/index.php/arctic/article/download/70428/54172; https://journalhosting.ucalgary.ca/index.php/arctic/article/download/70428/54171

The circumpolar Arctic ringed seal (Pusa hispida) occupies its fast-ice breeding habitat for four to five months during winter and the pack ice or open water of adjacent areas for the rest of the year. From 1971 – 78 and 1992 – 2019, we sampled approximately 100 ringed seals annually from western Prince Albert Sound (WPAS), the prime ringed seal fast-ice breeding habitat in Canada’s Western Arctic, adjacent to primary overwinter foraging habitat in eastern Amundsen Gulf (EAG). As our metric of body condition, we measured ventral blubber depth corrected for body size. As our metrics of reproduction, we measured the annual ovulation rate of multiparous females and percent pups in the open-water harvest. We examined these biological parameters in relation to the winter Arctic Oscillation Index (winAOI) and the timing of sea ice clearance in EAG in spring. There were no significant effects of age or sample month (June or July) on adult blubber depth, but significant sex and year effects and, in females, ovulation status effects. Across the series, as we have observed previously through 2011, there was a sustained temporal declining trend in blubber depth in adults of both sexes. There was no temporal trend in residual blubber depth, no correlation between blubber depth and sea ice clearance date in EAG, and a quasi-cyclic pattern in blubber depth that tracked some of the phases of the winAOI. Annual ovulation rates were mainly in the 80% – 100% range and correlated with percent pups in the open harvest in the same year. Three (1974, 2005, 2012) of the 36 y experienced reproductive failures, when over 50% of the multiparous females failed to ovulate. In each case, ovulation rates returned to normal within 1 – 3 y. Low annual ovulation rates were correlated with late sea ice clearance in EAG in spring, with two widespread ovulation failure events taking place in years when spring sea ice clearance was delayed by five to six weeks. The most recent ovulation failure (2012) differed in that it came in an average ice year ...