Abstract Johansson ML, Lavigne SY, Ramcharan CW, Heath DD, MacIsaac HJ. Detecting a spreading non-indigenous species using multiple methodologies. Lake Reserv Manage. 36:432–443. Non-indigenous species (NIS) are often introduced to novel environments at very low population abundance. Detecting the presence of such an NIS can be very challenging, particularly as it spreads from the initial establishment site. This provides an opportunity to test detection limits using different approaches. This study tested the detection capability of 3 methods as zebra mussels (Dreissena polymorpha) spread from south to north through Lake Winnipeg, Manitoba, Canada. Zebra mussel veliger larvae were detected using cross-polarized light microscopy (CPLM), flow cytometry and microscopy (FlowCam), and conventional polymerase chain reaction (cPCR) analysis of environmental DNA (eDNA) on the same samples. Abundance generally declined from south to north in the lake but was lowest at Calder’s Dock (central). Although abundances could be quite low (i.e., <1 veliger/m3, Calder’s Dock) CPLM prevalence—the percentage of samples with at least one veliger—was high throughout the lake (99–100% of samples). Prevalence was lower for cPCR and FlowCam but was statistically associated with veliger abundance. Using standardized 3 mL subsamples (0.06–0.18 m3 of lake water sampled), all 3 methods had a high probability of veliger detection if large numbers of samples were processed. FlowCam was the most expensive method to process these 3 mL subsamples, while cPCR was least expensive and fastest. eDNA combined with intensive sampling is the most practical method for wide-scale monitoring programs for early detection. However, all 3 methods are complementary and could be deployed sequentially, with rapid initial sample processing using PCR, confirmation and density estimation with FlowCam, and detailed veliger counts using CPLM.

中文翻译：

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使用多种方法检测传播的非本土物种

摘要 Johansson ML、Lavigne SY、Ramcharan CW、Heath DD、MacIsaac HJ。使用多种方法检测传播的非本土物种。湖泊保护区管理。36:432–443。非本土物种 (NIS) 经常以极低的种群丰度被引入新环境。检测此类 NIS 的存在可能非常具有挑战性，特别是当它从初始建立地点传播时。这提供了使用不同方法测试检测限的机会。本研究测试了 3 种方法的检测能力，因为斑马贻贝 (Dreissena polymorpha) 从南到北穿过加拿大曼尼托巴省的温尼伯湖。使用交叉偏振光显微镜 (CPLM)、流式细胞术和显微镜 (FlowCam) 检测斑马贻贝 veliger 幼虫，以及对相同样本的环境 DNA (eDNA) 进行常规聚合酶链反应 (cPCR) 分析。湖中的丰度普遍从南到北下降，但在考尔德码头（中部）最低。尽管丰度可能相当低（即 <1 veliger/m3，Calder's Dock），但 CPLM 流行率——至少有一个 veliger 的样本百分比——在整个湖中都很高（99-100% 的样本）。cPCR 和 FlowCam 的患病率较低，但在统计上与 veliger 丰度相关。使用标准化的 3 mL 子样品（采样的湖水 0.06-0.18 m3），如果处理大量样品，所有 3 种方法都有很高的 veliger 检测概率。FlowCam 是处理这些 3 mL 子样本的最昂贵的方法，而 cPCR 是最便宜和最快的方法。eDNA 结合密集采样是用于早期检测的大规模监测计划的最实用方法。然而，所有 3 种方法都是互补的，可以顺序部署，使用 PCR 进行快速初始样本处理，使用 FlowCam 进行确认和密度估计，并使用 CPLM 进行详细的 veliger 计数。