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Challenges and Opportunities for Linking Riverscape Thermal Regimes to Fish Populations
Citation:
Ebersole, J., M. Snyder, AND N. Schumaker. Challenges and Opportunities for Linking Riverscape Thermal Regimes to Fish Populations. Society for Freshwater Science – PNW Chapter, Newport, OR, November 06 - 08, 2019.
Impact/Purpose:
Many rivers and streams in the Pacific Northwest are currently listed as impaired under the Clean Water Act as a result of high summer water temperatures. Adverse effects of warm waters include impacts to fish populations that may already be stressed by habitat alteration, disease, predation, and fishing pressures. Much effort is being expended to improve conditions for fish, and methods are needed to project anticipated benefits of water temperature improvements, or costs of impairments. This presentation will describe two approaches being applied by the EPA to link changes in water temperatures to fish population responses.
Description:
Assessing the potential effects of altered regimes on fish populations is complicated by variation in fish movement and behavior, and environmental heterogeneity. Quantifying the value of both small and large scale thermal features to fish populations has been challenging due to the difficulty of mapping thermal regimes at biologically relevant spatial and temporal resolutions, and integrating thermal regimes into population models. We attempt to address these challenges by using newly-available datasets and modeling approaches to link thermal regimes to fish populations across scales. We discuss the challenges and opportunities to simulating fish behaviors and linking thermal exposures to migratory and reproductive fitness. We describe two approaches: an individual-based modeling approach useful for tracking implications of behavioral decision-making by fish, and a population modeling approach that incorporates species interactions, habitat effects, and movement.