Received: 7 April 2021 Revised: 27 July 2021 Accepted: 28 July 2021 DOI: 10.1002/rra.3845 RESEARCH ARTICLE InSTREAM 7: Instream flow assessment and management model for stream trout Steven F. Railsback1 | Daniel Ayllon 2 | Bret C. Harvey3 1Department of Mathematics, Humboldt State University and Lang Railsback and Associates, Abstract Arcata, California, USA Mechanistic, individual-based simulation models have been used for >25 years to 2 Faculty of Biology, Department of overcome well-known limitations of “habitat suitability” models. InSTREAM 7 is the Biodiversity, Ecology and Evolution, Complutense University of Madrid (UCM), latest of our individual-based models for predicting the effects of flow and tempera- Madrid, Spain ture regimes on stream salmonid populations. Unlike PHABSIM (or other methods 3Pacific Southwest Research Station, USDA “ ” Forest Service, Arcata, California, USA based on habitat quality, e.g., as net rate of energy intake), inSTREAM mechanisti- cally represents specific effects of flow and temperature on all life stages, and how Correspondence Steven F. Railsback, Department of those effects combine into testable predictions of population measures such as abun- Mathematics, Humboldt State University and dance, relative abundance of multiple trout species, and persistence. InSTREAM 7 is Lang Railsback and Associates, Arcata, CA 95521, USA. the first version to also represent the daily light cycle (dawn, day, dusk, and night) Email:
[email protected] and how feeding, predation risk, and individual behavior vary among light phases. An Funding information example assessment illustrates the importance of inSTREAM's multiple mechanisms: River Ecology & Management Research Group predicted trout population response to flow and temperature regimes depended on of Karlstad University and Vattenfall AB (Sweden); Pacific Southwest Research Station, the effects of sub-lethal temperatures on feeding behavior and effects of tempera- U.S.