Water diversions are very common in agricultural landscapes, providing water to irrigate a diverse range of crops. Larval Pacific Lamprey Entosphenus tridentatus are vulnerable to entrainment during the irrigation withdrawals and can be exposed to desiccation or predation during dewatering at the end of the irrigation season. A customized portable deepwater electrofishing system was deployed to determine larval lamprey densities at two large scaled irrigation diversion canals located on the Yakima River in eastern Washington. The system components can be easily transported to a remote survey site due the number of components and minimal total weight. The surveys were conducted in the fall during the dewatering period in 2015 and 2017, and the densities for larval lampreys ranged from 0.8 to 8.8 fish/m² at the Sunnyside Canal and 4.2 fish/m² at the Wapato Canal (2015 only). Our results indicate that the use of the deepwater electroshocking system was effective at determining larval lamprey presence and densities in hard-to-sample irrigation canals.

中文翻译：

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使用定制的便携式深水电鱼评估灌溉渠中的七鳃鳗幼虫种群

引水在农业景观中非常普遍，为灌溉各种作物提供水源。幼体太平洋七鳃鳗 Entosphenus tridentatus在灌溉撤水过程中容易受到夹带，并且在灌溉季节结束时的脱水过程中可能会受到干燥或捕食。部署了定制的便携式深水电捕鱼系统，以确定位于华盛顿东部亚基马河上的两个大型灌溉分流运河的七鳃鳗幼虫密度。由于组件数量多且总重量极小，系统组件可以轻松运输到远程调查站点。调查于 2015 年和 2017 年的秋季脱水期间进行，七鳃鳗幼虫的密度范围为 0.8 至 8.8 条/平方米^{2 个}在 Sunnyside 运河和 4.2 条鱼/m ²在 Wapato 运河（仅限 2015 年）。我们的结果表明，深水电击系统的使用可有效确定难以取样的灌溉渠中七鳃鳗幼虫的存在和密度。