Fundamental knowledge on free-ranging animals has been obtained through capture-based studies; however, these may be logistically intensive, financially expensive, and potentially inconsistent with local cultural values. Genetic mark–recapture using remote tissue sampling has emerged as a less invasive alternative to capture-based population surveys but provides fewer opportunities to collect samples and measurements for broader ecological studies. We compared lipid content, fatty acid (FA) composition, and diet estimates from adipose tissue of polar bears (Ursus maritimus) obtained from two collection methods: remote biopsies (n = 138) sampled from helicopters and hunter-collected tissue (n = 499) from bears harvested in Davis Strait and Gulf of Boothia, Nunavut, 2010 – 2018. Lipid content of adipose tissue was lower in remote biopsies than harvest samples likely because remote biopsies removed only the outermost layer of subcutaneous tissue, rather than the more metabolically dynamic innermost tissue obtained from harvest samples. In contrast, FA composition was similar between the two collection methods with relatively small proportional differences in individual FAs. For diet estimates in Davis Strait, collection method was not a predictor of prey contribution to diet. In Gulf of Boothia, collection method was a predictor for some prey types, but the differences were relatively minor; the rank order of prey types was similar (e.g., ringed seal; Pusa hispida was consistently the primary prey in diets) and prey proportions differed by < 6% between the collection methods. Results from both methods showed that diets varied by geographic area, season, year, age class, and sex. Our study demonstrates that adipose tissue from remote biopsy provides reliable estimates of polar bear diet based on FA analysis and can be used to monitor underlying ecological changes in Arctic marine food webs.

中文翻译：

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通过远程活检获得的组织样本对散养食肉动物的脂肪酸饮食分析有用吗？

通过基于捕获的研究获得了关于自由放养动物的基本知识；然而，这些可能是后勤密集型、经济上昂贵的，并且可能与当地文化价值观不一致。使用远程组织采样的遗传标记重新捕获已成为基于捕获的人口调查的侵入性较小的替代方案，但为更广泛的生态研究收集样本和测量的机会较少。我们比较了通过两种收集方法获得的北极熊（Ursus maritimus）脂肪组织的脂质含量、脂肪酸（FA）组成和饮食估计值：从直升机和猎人收集的组织中取样的远程活检（n = 138）和猎人收集的组织（n = 499） ) 来自于 2010 年至 2018 年在努纳武特的戴维斯海峡和布西亚湾收获的熊。远程活检中脂肪组织的脂质含量低于收获样本，这可能是因为远程活检仅去除了皮下组织的最外层，而不是从收获样本中获得的代谢更动态的最内层组织。相比之下，两种收集方法之间的 FA 组成相似，单个 FA 的比例差异相对较小。对于戴维斯海峡的饮食估计，收集方法不能预测猎物对饮食的贡献。在布西亚湾，收集方法是某些猎物类型的预测指标，但差异相对较小；猎物类型的等级顺序相似（例如，环斑海豹；Pusa hispida 一直是饮食中的主要猎物），猎物比例相差 <; 收集方法之间的 6%。两种方法的结果表明，饮食因地理区域、季节、年份、年龄层和性别而异。我们的研究表明，来自远程活检的脂肪组织基于 FA 分析提供了对北极熊饮食的可靠估计，并可用于监测北极海洋食物网中潜在的生态变化。