Experimental predation studies were conducted to evaluate and compare the predation threats of 10 species of native and non‐native fishes on larvae of Pacific Lamprey, Entosphenus tridentatus, and Western Brook Lamprey, Lampetra richardsoni. The relative predatory threats were examined over four sets of binary factors, including the following: (a) short (2‐day) or long (7‐day) duration, (b) presence/absence of fine sediment, (c) live or dead larvae and (d) species of lampreys. Our short‐term results showed a positive correlation with the sizes of predator fishes and consumed lamprey larvae. Also, most predator fishes had a significantly higher propensity to prey on lamprey larvae when sediment was absent. Conversely, this demonstrated the importance of sediment in protecting lamprey larvae from predation. Based on the predatory behaviour for live and dead larvae, predator fishes were classified into four groups using principal component analysis. Predation rates of larvae in sediment by piscivorous predators including Northern Pikeminnow Ptychocheilus oregonensis and Smallmouth Bass Micropterus dolomieu were lower and showed no differences even when the study duration was extended. In contrast, predation rates by benthic predators including White Sturgeon Acipenser transmontanus and Common Carp Cyprinus carpio, increased when we extended the study duration. This suggests that when given longer duration, benthic predators are more adept at consuming larvae within the sediment. These results provide important context for assessing the potential threat of predation on lampreys in streams, which is a key knowledge gap for lampreys.

中文翻译：

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一项评估美国哥伦比亚河流域本地幼虫七lamp鳗捕食威胁的实验研究

进行了实验性捕食研究，以评估和比较10种本地和非本地鱼类对太平洋南Lamp鳗（Entosphenus tridentatus）和西部布鲁克南Lamp（Lampetra richardsoni）幼虫的威胁。在四组二元因素中检查了相对掠夺性威胁，包括：（a）持续时间短（2天）或长（7天），（b）是否存在细小沉积物，（c）活的或死幼虫和（d）七lamp鳗。我们的短期结果显示，它们与捕食鱼的大小和食用的七lamp鳗幼虫呈正相关。而且，在缺乏沉积物的情况下，大多数掠食性鱼类对lamp鱼幼虫的捕食倾向明显更高。相反，这证明了沉积物在保护七lamp鳗幼虫免遭捕食方面的重要性。根据活体和死亡幼体的捕食行为，使用主成分分析将捕食鱼分为四类。包括北派克米诺鱼在内的食肉性捕食者对沉积物中幼虫的捕食率俄勒冈假单胞菌（Ptychocheilus oregonensis）和小口鲈微缩孢子虫（dolpheueu）较低，即使延长研究时间也没有差异。相比之下，底栖食肉动物包括白鲟捕食率鲟transmontanus和鲤鱼鲤鱼，增加了当我们扩展了研究时间。这表明，如果持续时间较长，底栖捕食者更善于消耗沉积物中的幼虫。这些结果为评估流中七context鳗的潜在威胁提供了重要背景，这是七lamp鳗的主要知识缺口。