Retrospective Study of Walrus Foraging and Movement Patterns During a Major Ecosystem Shift in the Bering and Chukchi Seas, Alaska, 1950-2010

This study developed a historic ~50-year time series of carbon (δ13C) and nitrogen (δ15N) isotope values with annual resolution to test the hypothesis about whether northward shift of benthic ecosystems is influencing walrus movement and diet, as well as the ecology of other benthic predators. Collected and archived Pacific walrus (Odobenus rosmarus divergens) teeth (lower canines) during subsistence harvests on Saint Lawrence Island. All teeth were originally collected from Native subsistence harvested animals except for one set of teeth collected in the Bering Sea during a research cruise conducted in 1981. Age via cementum annuli counts were estimated and targeted teeth from younger animals (<15 years old). Teeth were recovered from collections made between 1960-2012. This dataset contains the estimated age and tooth dentin carbon (δ13C) and nitrogen (δ15N) isotope values of male and female walrus collected over the past ~50 years from subsistence harvests.

本研究构建了一套分辨率为年际的近50年碳（δ¹³C）与氮（δ¹⁵N）同位素时间序列，旨在验证“底栖生态系统北移是否会影响海象的活动与食性，以及其他底栖捕食者的生态状况”这一假说。研究人员在圣劳伦斯岛（Saint Lawrence Island）的本土居民生存性捕捞活动中采集并存档了太平洋海象（Odobenus rosmarus divergens）的下犬齿；除1981年一次科考巡航期间在白令海（Bering Sea）采集的一组牙齿外，所有牙齿均来自经本土居民生存性捕捞获取的个体。本研究通过牙骨质环纹计数估算个体年龄，并选取了15岁以下个体的目标牙齿。所有牙齿样本均采集自1960年至2012年间的馆藏标本。本数据集涵盖了近50年间通过生存性捕捞获取的雌雄海象的估算年龄，以及其牙齿牙本质的碳（δ¹³C）与氮（δ¹⁵N）同位素值。