Abstract Animal populations are assessed to estimate rates of artificial and natural mortality at ecologically relevant spatial and temporal scales to develop exploitation quotas. But how the population’s natural mortality rate and how the ability to observe the population changes through time are poorly understood in most invasive fishes, despite efforts to control their populations. By investigating a 30-year abundance index of invasive sea lamprey (Petromyzon marinus) in Lake Superior, we found that the index was highly correlated (R2 = 0.75) with biotic and abiotic factors hypothesized to influence sea lamprey natural mortality and their availability to index traps. The index was lowest in years (1) following winters with below average ice cover on Lake Superior, (2) when stream discharge during sea lamprey migration was below average, (3) when adult sea lamprey were smaller than average, and (4) when adult sea lamprey were more likely to be distributed in tributaries on the east side of Lake Superior. These results highlight the need for policy makers to consider invasive species abundance indexes not just in the context of control effort, but also in the context of biotic and abiotic conditions because they could markedly influence natural mortality or the ability to observe highly suppressed populations.

中文翻译：

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冬季的严重程度、鱼类群落和陷阱的可用性解释了苏必利尔湖成年海七鳃鳗估计值的大部分变化

摘要 评估动物种群以估计生态相关时空尺度上的人为和自然死亡率，以制定开发配额。但是，尽管努力控制它们的种群，但在大多数入侵鱼类中，人们对种群的自然死亡率以及观察种群随时间变化的能力如何变化知之甚少。通过调查苏必利尔湖侵入性海七鳃鳗 (Petromyzon marinus) 的 30 年丰度指数，我们发现该指数与生物和非生物因素高度相关 (R2 = 0.75)，假设影响海七鳃鳗自然死亡率及其可利用性陷阱。该指数在以下年份中最低 (1) 苏必利尔湖冰盖低于平均水平的冬季，(2) 海七鳃鳗迁移期间的河流流量低于平均水平，(3) 成年海七鳃鳗小于平均时，以及 (4) 成年海七鳃鳗更可能分布在苏必利尔湖东侧的支流中。这些结果突出表明，决策者需要不仅在控制工作的背景下，而且在生物和非生物条件的背景下考虑入侵物种丰度指数，因为它们可以显着影响自然死亡率或观察高度抑制种群的能力。