Environmental conditions in the Chukchi Sea are changing rapidly and may alter the abundance and distribution of marine species and their benthic prey. We used a metabarcoding approach to identify potentially important prey taxa from Pacific walrus (Odobenus rosmarus divergens) fecal samples (n = 87). Bivalvia was the most dominant class of prey (66% of all normalized counts) and occurred in 98% of the samples. Polychaeta and Gastropoda occurred in 70% and 62% of the samples, respectively. The remaining nine invertebrate classes comprised <21% of all normalized counts. The common occurrence of these three prey classes is consistent with examinations of walrus stomach contents. Despite these consistencies, biases in the metabarcoding approach to determine diet from feces have been highlighted in other studies and require further study, in addition to biases that may have arisen from our opportunistic sampling. However, this noninvasive approach provides accurate identification of prey taxa from degraded samples and could yield much‐needed information on shifts in walrus diet in a rapidly changing Arctic.

中文翻译：

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粪便的DNA metabarcoding推断太平洋海象的夏季饮食

楚科奇海的环境条件正在迅速变化，并可能改变海洋物种及其底栖动物的数量和分布。我们使用元条形码方法从太平洋海象（Odobenus rosmarus divergens）粪便样本（n= 87）。双壳纲是最主要的猎物类（占所有归一化计数的66％），并且在98％的样本中均发生。分别在70％和62％的样品中出现了多毛菌属和腹足纲。其余9个无脊椎动物类别占所有归一化计数的<21％。这三种猎物类别的普遍发生与海象胃内容物的检查一致。尽管存在这些一致性，但在其他研究中也强调了在metabarcoding方法中从粪便中确定饮食的偏见，除了机会抽样可能引起的偏见之外，还需要进一步研究。但是，这种非侵入性方法可以从降解的样本中准确识别猎物类群，并且可以在急速变化的北极地区提供海象饮食变化所急需的信息。