A single‐species environmental DNA (eDNA) method was developed to sample for a small, benthic rare species, Eastern Sand Darter (Ammocrypta pellucida Putnam, 1863) in two large Lake Ontario embayments. Summer water sampling allowed for: (a) surveys of habitats (Wellers Bay) where traditional fish sampling gear could not be used; and, (b) a comparison between eDNA and seining‐based detection probabilities at known occupied habitats (West Lake). In 2018, replicate (n = 3) 1 L water samples were collected from 90 Wellers Bay sites and 71 West Lake sites. A site‐occupancy model, a hierarchical logistic regression model, was fitted to determine site occupancy, sample occupancy (presence of Eastern Sand Darter DNA in a water sample) and probability of detection (p) based on replicate quantitative polymerase chain reaction (qPCR) results for each water sample. Eastern Sand Darter was detected at 10 West Lake sites, but not from Wellers Bay. Mean site occupancy was 0.31 (0.12–0.70; 95% CLs), mean sample occupancy was 0.28 (0.09–0.58; 95% CLs), and mean detection probability in a subsample (i.e., successful qPCR amplification) given it was present was 0.40 (0.25–0.55; 95% CLs). While the eDNA method successfully detected Eastern Sand Darter from known occupied areas in West Lake, it was not more effective for assessing local site occupancy than traditional sampling methods, such as the seine.

中文翻译：

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利用环境DNA检测大型Laurentian大湖隔离区内的东部沙Sand（Ammocrypta pellucida Putnam，1863）

开发了一种单物种环境DNA（eDNA）方法，以在两个安大略湖大隔离区内采样一个小的底栖稀有物种东部沙镖（Ammocrypta pellucida Putnam，1863）。夏季水采样可用于：（a）无法使用传统鱼类采样工具的栖息地（韦勒斯湾）调查；（b）在已知的被占领栖息地（西湖）的eDNA与基于围网的检测概率之间的比较。在2018年， 从90个Wellers Bay站点和71个西湖站点采集了重复（n = 3）1 L水样品。场地占用模型（分层逻辑回归模型）适用于确定场地占用，样品占用（水样品中存在Eastern Sand Darter DNA）和检测概率（p）基于每个水样品的重复定量聚合酶链反应（qPCR）结果。在西湖的10个地点发现了“东部飞镖”，但未在韦尔斯湾发现。平均位点占用率为0.31（0.12-0.70; 95％CLs），平均样品占用率为0.28（0.09-0.58; 95％CLs），并且如果存在，则在子样品中（即成功的qPCR扩增）的平均检测概率为0.40 （0.25-0.55； 95％CL）。尽管eDNA方法成功地从西湖的已知占领区中检测到了东部飞镖，但它对评估当地场地的占用没有比传统的采样方法（如塞纳河）更有效。