Demographic, ecological and physiological responses of ringed seals to an abrupt decline in sea ice availability

• Main Authors: Ferguson, Steven H, Young, Brent G, Yurkowski, David J, Anderson, Randi, Willing, Cornelia, Nielsen, Ole
• Format: Other/Unknown Material
• Language: unknown
• Published: PeerJ 2016
• Subjects: Arctic; Hudson; Hudson Bay; inuit; Pusa hispida; ringed seal; Sea ice
• Online Access: http://dx.doi.org/10.7287/peerj.preprints.2309; https://peerj.com/preprints/2309.pdf; https://peerj.com/preprints/2309.xml; https://peerj.com/preprints/2309.html

To assess whether demographic declines of Arctic species at the southern limit of their range will be gradual or punctuated, we compared large-scale environmental patterns including sea ice dynamics to ringed seal ( Pusa hispida ) reproduction, body condition, recruitment, and stress in Hudson Bay from 2003-2013. Aerial surveys suggested a gradual decline in seal density from 1995-2013, with the lowest density occurring in 2013. Body condition decreased and stress (cortisol) increased over time in relation to longer open waterperiods. The 2010 open water period in Hudson Bay coincided with extremes in large-scale atmospheric patterns (NAO, AO, ENSO) resulting in the earliest spring breakup and the latest ice formation on record. The warming event was coincident with the highest stress levels and the lowest recorded ovulation rate and low pregnancy rate, few pups in the Inuit harvest, and observations of sick seals. We conclude that although negative demographic responses of Hudson Bay seals are occurring gradually with diminishing sea ice, a recent episodic environmental event played a significant role in a punctuated population decline.