School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, United States.
Washington Water Science Center, US Geological Survey, Tacoma, WA, United States.
Sci Total Environ. 2018 Jun 1;625:1003-1012. doi: 10.1016/j.scitotenv.2017.12.327. Epub 2018 Jan 5.
Expanding human population and urbanization alters freshwater systems through structural changes to habitat, temperature effects from increased runoff and reduced canopy cover, altered flows, and increased toxicants. Current stream assessments stop short of measuring health or condition of species utilizing these freshwater habitats and fail to link specific stressors mechanistically to the health of organisms in the stream. Juvenile fish growth integrates both external and internal conditions providing a useful indicator of habitat quality and ecosystem health. Thus, there is a need to account for ecological and environmental influences on fish growth accurately. Bioenergetics models can simulate changes in growth and consumption in response to environmental conditions and food availability to account for interactions between an organism's environmental experience and utilization of available resources. The bioenergetics approach accounts for how thermal regime, food supply, and food quality affect fish growth. This study used a bioenergetics modeling approach to evaluate the environmental factors influencing juvenile coho salmon growth among ten Pacific Northwest streams spanning an urban gradient. Urban streams tended to be warmer, have earlier emergence dates and stronger early season growth. However, fish in urban streams experienced increased stress through lower growth efficiencies, especially later in the summer as temperatures warmed, with as much as a 16.6% reduction when compared to fish from other streams. Bioenergetics modeling successfully characterized salmonid growth in small perennial streams as part of a more extensive monitoring program and provides a powerful assessment tool for characterizing mixed life-stage specific responses in urban streams.
人口增长和城市化通过改变栖息地结构、增加径流量和减少树冠覆盖导致的温度效应、改变水流以及增加有毒物质等方式改变了淡水系统。目前的溪流评估未能衡量利用这些淡水生境的物种的健康或状况，也未能将特定的胁迫因素与溪流中生物的健康在机制上联系起来。鱼类幼体生长综合了外部和内部条件，为栖息地质量和生态系统健康提供了一个有用的指标。因此，需要准确考虑生态和环境对鱼类生长的影响。生物能量学模型可以模拟生长和消耗随环境条件和食物供应的变化，以解释生物体的环境经验与其利用可用资源之间的相互作用。生物能量学方法考虑了热区、食物供应和食物质量如何影响鱼类生长。本研究使用生物能量学建模方法来评估影响太平洋西北地区 10 条溪流中幼年银鲑生长的环境因素，这些溪流跨越了城市梯度。城市溪流往往更温暖，出现日期更早，早期生长更强。然而，由于生长效率较低，城市溪流中的鱼类会经历更多的压力，尤其是在夏季后期，随着温度升高，与其他溪流的鱼类相比，其生长效率降低了高达 16.6%。生物能量学建模成功地描述了小型常年溪流中的鲑鱼生长情况，作为更广泛监测计划的一部分，并为描述城市溪流中混合生命阶段特定反应提供了强大的评估工具。
