Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers

• DOI: 10.1371/journal.pone.0255686
• Publication Date: 2021-08-19T18:39:52Z
• Authors: Chelsea W. Koch; Lee W. Cooper; Ryan J. Woodland; Jacqueline M. Gre...; Karen E. Frey; Raphaela Stimmelmayr; Cédric Magen; Thomas A. Brown
• Keywords: Isotope Analysis; Marine ecosystem; δ15N

The expected reduction of ice algae with declining sea may prove to be detrimental the Pacific Arctic ecosystem. Benthic organisms that rely on organic carbon (iPOC) sustain benthic predators such as walrus (Odobenus rosmarus divergens). ability track trophic transfer iPOC is critical understanding its value in food web, but prior methods have lacked required source specificity. We analyzed H-Print index, based biomarkers versus phytoplankton contributions marine predators, livers collected 2012, 2014 and 2016 from Northern Bering Sea (NBS) Chukchi Sea. paired these measurements stable nitrogen isotopes (δ15N) estimate position. observed differences contribution diet between regions, sexes, age classes. Specifically, walruses was higher (52%) compared NBS (30%). This regional difference consistent longer annual persistence Within NBS, spring females (~45%) males (~30%) for each year (p < 0.001), likely due specific foraging behavior support energetic demands associated pregnancy lactation. Sea, similar females, yet juveniles than adults. Despite origin fueling system (sea pelagic derived carbon), position adult female (3.2 3.5, respectively), supporting diets (i.e. clams). Given quality algae, retreat seasonal recent decades create an additional vulnerability juvenile should considered management species.