Population vital rates, such as stage-specific survival, are influenced by individual behavior and movement patterns. Yet few methods exist to incorporate behavior into predator-prey models, omitting a potentially important source of variability in population dynamics. Here were combine results from an acoustic telemetry study of juvenile Chinook salmon (Oncorhynchus tshawytscha) with an existing predator prey model, called the mean free-path length model, originally presented in Anderson et al. (2005). The model describes the probability of predator-prey encounters as a function of the predator density and the movement patterns of predators and prey. Greater predator densities and greater variation in movement vectors should result in higher predator-prey encounter rates, and lower survival for the prey. Fitting this model to data provides insight into mechanisms of mortality for migrating fishes. Here we estimate model parameters for two flow conditions in the Sacramento River, California, examining the importance of natural environmental variation in shaping encounters and prey survival. Survival estimates were similar between the high and low flow conditions, yet travel time was slower at lower flows. The model estimates of mean free-path length were lower when compared to those estimated in the Snake River system, corresponding with lower survival. We discuss the value of model parameters estimated from telemetry data in providing a tool for forecasting population-level responses to structural or hydrodynamic modifications in large river systems, and we explore how the XT model can provide insight into nonlinear and threshold-like responses of migratory fish survival to flow.

中文翻译：

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将平均自由程长度模型应用于在加利福尼亚州萨克拉门托河洄游的幼年奇努克鲑鱼

人口生命率，例如特定阶段的存活率，受个人行为和运动模式的影响。然而，很少有方法将行为纳入捕食者-猎物模型，从而忽略了种群动态变化的潜在重要来源。以下是对幼年奇努克鲑鱼 (Oncorhynchus tshawytscha) 的声学遥测研究与现有捕食者猎物模型（称为平均自由路径长度模型）的结合结果，该模型最初由 Anderson 等人提出。(2005)。该模型将捕食者与猎物相遇的概率描述为捕食者密度以及捕食者和猎物的运动模式的函数。更大的捕食者密度和更大的运动向量变化应该会导致更高的捕食者-猎物遭遇率，并降低猎物的存活率。将此模型与数据拟合可深入了解洄游鱼类的死亡率机制。在这里，我们估计加利福尼亚州萨克拉门托河的两种流动条件的模型参数，检查自然环境变化在塑造遭遇和猎物生存方面的重要性。高流量和低流量条件下的生存估计值相似，但在低流量条件下旅行时间较慢。与蛇河系统中的估计值相比，平均自由路径长度的模型估计值较低，对应于较低的存活率。我们讨论了从遥测数据估计的模型参数的价值，它提供了一种工具，用于预测人口对大型河流系统中结构或水动力变化的响应，