ABSTRACT: Increasing grey seal Halichoerus grypus abundance in coastal New England is leading to social, political, economic, and ecological controversies. Central to these issues is the foraging ecology and diet composition of the seals. We studied grey seal feeding habits through next-generation sequencing of prey DNA using 16S amplicons from seal scat (n = 74) collected from a breeding colony on Monomoy Island in Massachusetts, USA, and report frequency of occurrence and relative read abundance. We also assigned seal sex to scat samples using a revised PCR assay. In contrast to current understanding of grey seal diet from hard parts and fatty acid analysis, we found no significant difference between male and female diet measured by alpha and beta diversity. Overall, we detected 24 prey groups, 18 of which resolved to species. Sand lance Ammodytes spp. were the most frequently consumed prey group, with a frequency of occurrence (FO) of 97.3%, consistent with previous studies, but Atlantic menhaden Brevoortia tyrannus, the second most frequently consumed species (FO = 60.8%), has not previously been documented in US grey seal diet. Our results suggest that a metabarcoding approach to seal food habits can yield important new ecological insights, but that traditional hard parts analysis does not underestimate consumption of Atlantic cod Gadus morhua (FO = 6.7%, Gadidae spp.) and salmon Salmo salar (FO = 0%), 2 particularly valuable species of concern.

中文翻译：

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利用下一代测序技术鉴定北大西洋西部海豹灰嘴猴饮食中的猎物DNA

摘要：灰海豹（Halichoerus grypus）的灰色纹章越来越多新英格兰沿海地区的人口众多导致社会，政治，经济和生态方面的争议。这些问题的核心是海豹的觅食生态和饮食组成。我们使用从美国马萨诸塞州莫诺莫伊岛的一个繁殖地收集的海豹粪便（n = 74）中的16S扩增子，通过猎物DNA的下一代测序研究了灰海豹的摄食习性，并报告了发生频率和相对阅读丰度。我们还使用改良的PCR分析法将粪便性别指定给粪便样本。与目前对硬部分和脂肪酸分析对灰海豹饮食的理解相反，我们发现通过α和β多样性测量的男性和女性饮食之间没有显着差异。总体而言，我们检测到24个猎物组，其中18个解析为物种。砂枪Ammodytesspp。是最常被捕食的猎物组，其发生频率（FO）为97.3％，与先前的研究一致，但第二个最常被捕食的物种（FO = 60.8％）的大西洋猛BreBravoortia tyrannus在以前没有被记录在案。美国灰海豹的饮食。我们的研究结果表明，通过密封条码来养成饮食习惯的方法可以产生重要的新生态学见解，但是传统的硬质成分分析并不能低估大西洋鳕鳕（Gadus morhua）（FO = 6.7％，Gadidae spp。）和鲑鱼Salmo salar（FO = 0％），2个特别有价值的物种。