The Pacific Lamprey Entosphenus tridentatus is an important species both ecologically and culturally, but their population numbers and range have declined severely in the past several decades in the Columbia Basin. In freshwater ecosystems, larval lampreys are candidate prey species for many fish predators, but little is known regarding the magnitude of predation they currently experience. Predation on larval Pacific Lampreys may be substantially underestimated by morphological gut content analysis because their soft bodies are quickly digested and leave no hard evidence, such as bones and scales. We conducted an experimental predation study and analyzed larval Pacific Lampreys in the gut contents of predators’ digestive tracts via both morphological and molecular methods. Whereas most consumed larval lampreys (67–100%) were morphologically unidentifiable within two nights, genetic species identification rates using four single nucleotide polymorphisms from stomachs were high (83%). The single nucleotide polymorphisms optimized for parentage in Pacific Lamprey also successfully identified the parents of four out of five Pacific Lampreys with complete genotypes. When a genetic baseline of candidate parents is available, this molecular technique using parentage-based tagging offers a novel method for determining precise characteristics of predation behavior in field studies, including the ages and natal origins of larvae being consumed.

中文翻译：

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你吃了谁的孩子？鱼类捕食者肠道中七鳃鳗幼体的物种和亲本的遗传鉴定

太平洋七鳃鳗Entosphenus tridentatus是生态和文化上的重要物种，但在过去的几十年里，哥伦比亚盆地的种群数量和范围急剧下降。在淡水生态系统中，七鳃鳗幼体是许多鱼类捕食者的候选猎物物种，但人们对它们目前所经历的捕食程度知之甚少。形态学肠道内容分析可能大大低估了太平洋七鳃鳗幼虫的捕食情况，因为它们柔软的身体很快被消化，没有留下任何确凿的证据，如骨骼和鳞片。我们进行了一项实验性捕食研究，并通过形态学和分子方法分析了捕食者消化道肠道内容物中的太平洋七鳃鳗幼虫。而大多数食用的七鳃鳗幼虫（67-100%）在两晚内在形态上无法识别，使用来自胃的四种单核苷酸多态性的遗传物种鉴定率很高（83％）。针对太平洋七鳃鳗亲本优化的单核苷酸多态性也成功鉴定了五只具有完整基因型的太平洋七鳃鳗中的四只的亲本。当候选父母的遗传基线可用时，这种使用基于亲本标记的分子技术提供了一种新方法，用于确定实地研究中捕食行为的精确特征，包括被食用的幼虫的年龄和出生起源。