An integrated drought early warning system to support coldwater fisheries management

Fisheries
By: , and 

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Abstract

Low streamflow resulting from drought and human water use is a threat to freshwater fisheries throughout western North America, creating a need for effective tools to aid management and fisheries use. We developed a drought early warning framework that forecasts river conditions that could result in temporary fishery closures and restrictions across Montana’s renowned trout fisheries. This tool provides reach-specific, probabilistic decision support for proactive management under drought conditions. We calibrated statistical models using historical streamflow and stream temperature data from U.S. Geological Survey (USGS) gauges to predict the likelihood of exceeding the low-flow and high-temperature thresholds for fisheries closure within 1- to 4-week outlooks during the warm season (May–October). These forecasts demonstrated consistently high model performance in predicting the criteria for low-flow fishing closure across all rivers (4-week outlook: mean R2 = 0.96, IQR [interquartile range]: 0.94–0.97) and variable but often high model performance for temperature-based restriction criteria (mean R2 = 0.80, IQR: 0.55–0.86), particularly at sites that frequently experience higher stream temperature conditions. This drought early warning system—available via the web-based tool TroutCast (https://www.usgs.gov/apps/troutcast/)—provides daily updated seasonal forecasts to help anticipate effects to recreational fishing opportunities. By quantifying forecast uncertainty and providing reach-specific probabilities, the system supports proactive management, improves coordination between fisheries and water managers, and provides stakeholders with actionable information on probable future effects on fishing access within a framework that is broadly applicable to other freshwater systems and water resource management challenges.

Suggested Citation

Martin, J.T., Pederson, G.T., Cline, T., Lahr, A.B., Walker, J.D., Schmetterling, D., Bell, D.A., and Muhlfeld, C.C., 2026, An integrated drought early warning system to support coldwater fisheries management: Fisheries, https://doi.org/10.1093/fshmag/vuag035.

ISSN: 1548-8446 (online)

Study Area

Publication type Article
Publication Subtype Journal Article
Title An integrated drought early warning system to support coldwater fisheries management
Series title Fisheries
DOI 10.1093/fshmag/vuag035
Edition Online First
Publication Date June 18, 2026
Year Published 2026
Language English
Publisher Oxford Academic
Contributing office(s) Northern Rocky Mountain Science Center
Country United States
State Montana
Additional publication details