Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
State-space population models are becoming a common tool to guide natural resource management, because they address the statistical challenges arising from high observation error and process variation while improving inference by integrating multiple, disparate datasets. A hierarchical state-space life cycle model was developed, motivated by delta smelt (Hypomesus transpacificus), an estuarine fish experiencing simultaneous risks of entrainment mortality from out-of-basin water export and natural mortality. Notable model features included a covariate-dependent instantaneous rates formulation of survival, allowing estimation of multiple sources of mortality, and inclusion of relative observation bias parameters, allowing integration of differently scaled abundance indices and entrainment estimates. Simulation testing confirmed that two sources of mortality, process variation, and data integration parameters could be estimated. Delta smelt entrainment mortality was associated with environmental conditions used to manage entrainment, and recruitment and natural mortality were related to temperature, freshwater flow, food, and predators. Although entrainment mortality was reduced in recent years, ecosystem conditions did not appear to support robust spawning or over-summer survival of new recruits, manifesting as a 98% reduction of adults during 1995–2015.

中文翻译：

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解开濒危鱼类的风险：使用状态空间生命周期模型将自然死亡与人为损失分开

加拿大渔业和水产科学杂志，提前印刷。
状态空间人口模型正成为指导自然资源管理的常用工具，因为它们解决了高观测误差和过程变化带来的统计挑战，同时通过整合多个不同的数据集来改进推理。由 delta smelt (Hypomesus transpacificus) 驱动，开发了一个分层状态空间生命周期模型，这是一种河口鱼类，同时经历流域外水出口和自然死亡的夹带死亡风险。值得注意的模型特征包括依赖于协变量的瞬时存活率公式，允许估计多个死亡率来源，并包含相对观察偏差参数，允许整合不同尺度的丰度指数和夹带估计。模拟测试证实可以估计死亡率、过程变异和数据集成参数的两个来源。Delta 冶炼夹带死亡率与用于管理夹带的环境条件有关，补充和自然死亡率与温度、淡水流量、食物和捕食者有关。尽管近年来夹带死亡率有所降低，但生态系统条件似乎并不支持新招募者的强劲产卵或过夏生存，表现为 1995-2015 年成年鱼减少了 98%。