Clear Lake Hitch is an imperilled minnow endemic to Clear Lake, Lake County, California, United States listed as threatened under the California Endangered Species Act (ESA) and a candidate for listing under the United States ESA. It exhibits a potamodromous life cycle whereby adults, which reach up to 6 + years in age and over 350 mm in length, migrate into Clear Lake's ephemeral tributaries briefly during spring to spawn. Conservation and management of Clear Lake Hitch is inhibited, in part, by a lack of information on the lacustrine habitat of nonbreeding individuals within Clear Lake. To address this problem, we sampled Clear Lake Hitch with gill nets in a stratified random sampling design to determine the distribution and habitat associations in early summer 2017 and 2018. We identified abundance‐habitat relationships for juveniles and adults using Bayesian zero‐inflated negative binomial generalised linear mixed modelling. Results indicated that dissolved oxygen concentration was the most important habitat feature measured; juveniles and adults were substantially more abundant in normoxic (≥2 mg/l) than in hypoxic (<2 mg/l) habitat. Both also exhibited weak positive relationships with chlorophyll fluorescence, suggesting relatively productive habitats may support higher numbers of Clear Lake Hitch. Spatially, juveniles were most abundant in nearshore habitats while adults were ubiquitous, indicating an ontogenetic habitat expansion that may be associated with a resource availability‐predation risk trade‐off. Management actions undertaken to improve hypoxia problems in Clear Lake would also improve Clear Lake Hitch habitat.

中文翻译：

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溶解氧控制着Clear Lake Hitch ( Lavinia exilicauda chi )的夏季栖息地，这是一种濒危的potamodromous cyprinid

Clear Lake Hitch 是美国加利福尼亚州莱克县 Clear Lake 特有的一种濒危小鱼，根据《加利福尼亚濒危物种法案》(ESA) 被列为受威胁物种，并且是美国 ESA 列出的候选者。它表现出一种生活周期，成年年龄可达 6 岁以上，身长超过 350 毫米，在春季短暂迁移到克利尔湖的短暂支流中产卵。由于缺乏关于 Clear Lake 内非繁殖个体的湖泊栖息地的信息，Clear Lake Hitch 的保护和管理在一定程度上受到抑制。为了解决这个问题，我们在分层随机抽样设计中对带有刺网的 Clear Lake Hitch 进行了抽样，以确定 2017 年和 2018 年初夏的分布和栖息地关联。我们使用贝叶斯零膨胀负二项式广义线性混合模型确定了幼鱼和成鱼的丰度-栖息地关系。结果表明，溶解氧浓度是测量到的最重要的栖息地特征；幼鱼和成鱼在常氧 (≥2 mg/l) 栖息地比在缺氧 (<2 mg/l) 栖息地更丰富。两者都与叶绿素荧光呈弱正相关，表明相对多产的栖息地可能支持更多数量的 Clear Lake Hitch。在空间上，幼鱼在近岸栖息地中最为丰富，而成鱼则无处不在，这表明个体发生的栖息地扩张可能与资源可用性-捕食风险的权衡有关。