Oceanographic influences on spotted seal foraging in the Pacific Arctic

Comparative Muscle Physiology of Ringed (Pusa hispida), Bearded (Erignathus barbatus), and Spotted (Phoca largha) Seals from the Bering and Chukchi Seas

“…The functional significance of these muscle fibers requires further exploration, but their existence reveals fundamental differences in the structure of bearded seal skeletal muscle relative to previously studied species. Further, bearded seals exhibit the highest proportion of fast-twitch Kelly & Wartzok, 1996;Gjertz et al, 2000a;Born et al, 2004;Crawford et al, 2019;i Lowry et al, 1998;Olnes et al, 2023;j London et al, 2014;k Lydersen & Kovacs, 1993;Folkow et al, 2004;l Folkow & Blix, 1999;m Gjertz et al, 2000b;Krafft et al, 2000;Olnes et al, 2020;n Born & Knutsen, 1997;Nowicki et al, 1997;Gjertz et al, 2001;Jay et al, 2001;o Lenfant et al, 1970;p Burns et al, 2007p Burns et al, , 2010q Lestyk et al, 2009;Burns et al, 2010;and r Noren et al, 2015 fibers (~68%) of any seal species reported to date. Although we did not differentiate fast-twitch fibers into fast oxidative glycolytic (type IIA) or fast glycolytic (type IIB) subtypes, previous studies suggest that other seals lack type IIB fibers altogether (Kanatous et al, 2002;Watson et al, 2003;Moore et al, 2014).…”

“…Environmental Change and Behavioral Flexibility Ringed, bearded, and spotted seals rely on sea ice to varying degrees, making them vulnerable to warming Arctic conditions (Kovacs et al, 2011;Laidre et al, 2015;Reimer et al, 2019;Olnes et al, 2023). The combined effects of sea ice loss, climate driven alterations in prey abundance, and corresponding changes in seal distribution may require that individuals modify routine behavior with changing environmental conditions.…”