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Using stable isotopes to understand changes in ringed seal foraging ecology as a response to a warming environment
Author(s) -
Young Brent G.,
Ferguson Steven H.
Publication year - 2014
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/mms.12075
Subject(s) - capelin , bay , arctic , δ13c , δ15n , ecology , foraging , stable isotope ratio , oceanography , isotope analysis , environmental science , predation , biology , geology , physics , quantum mechanics
Trends toward increased temperatures, reduced sea ice extent, and longer open water seasons have resulted in changing Arctic ecosystem dynamics. Expected changes include shifts in distribution and abundance of prey species for seabirds and marine mammals. Using stable isotope analysis, we studied spatial and interannual variation in ringed seal ( Pusa hispida) feeding ecology in Hudson Bay in relation to environmental variables, between 2003 and 2010. Ringed seal muscle and hair samples collected from Arviat and Sanikiluaq, Nunavut, were analyzed for stable isotope ratios of nitrogen ( δ 15 N) and carbon ( δ 13 C). Seals from western Hudson Bay (Arviat) had higher δ 15 N and lower δ 13 C than seals from eastern Hudson Bay (Sanikiluaq), and stable isotope ratios varied interannually within each region. Peak δ 15 N occurred in years with spring air temperatures between approximately −5°C and −2°C. This temperature range was characteristic of warm years in western Hudson Bay and cool years in eastern Hudson Bay. We hypothesize that the high δ 15 N observed in ringed seals is indicative of greater importance of capelin ( Mallotus villosus ) in ringed seal diet. A comparison of ringed seal isotopic niche widths indicated greater dietary differences between western and eastern Hudson Bay with warming, suggesting a possible ecological divergence related to climate change.