Schoen, E., Falke, J., Paul, J., Meyer, B., Neuswanger, J., Strohm, D., McKenna, B., Lynne, D., and Savereide, J. 2023. How Do Wildfires Affect Alaskan Chinook Salmon? Evidence from Rivers and Satellites. American Fisheries Society Annual Meeting, Grand Rapids, MI, August 20-24, 2023.
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August 2023
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Wildfires are becoming more frequent in Alaska's boreal ecosystems, but their effects on rivers and salmon are not well understood. One year after wildfires bisected an important Chinook salmon habitat, we found fire-affected sites were slightly warmer and more turbid than upstream reference sites, but food resources and juvenile salmon growth were similar. Satellite measurements across a broader study area showed historic wildfires warmed the land surface for > 15 years, resulting in complex e
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Samuel, W. T., J. A. Falke, K. D. Tape, S. K. Panda, A. C. Seitz. 2023. When beavers get burned, do fish get fried? The role of beavers in mediating wildfire effects on freshwater fish habitat in boreal Alaska. American Fisheries Society 153nd Annual Meeting, Grand Rapids, MI. August 20–24.
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August 2023
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Little is known about how wildfire affects fish habitat and populations in boreal streams despite the substantial impacts of fire on ecosystem processes, and how fire effects may be mediated by species interactions. This study will help to provide a better understanding of the role of beavers in maintaining diverse and productive aquatic habitats in riverscapes under changing wildfire conditions.
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Rich, B., Westley, P., Sepulveda, A., Rinella, D., Falke, J., and E. Schoen. 2023. Introduced northern pike predation and consumption of juvenile salmon in a warming world. Matanuska-Susitna Salmon Habitat Partnership Symposium. 13-14 November, 2023. Palmer, AK.
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November 2023
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Global climate change may be exacerbating the impacts of invasive species such as Northern Pike in warming Alaska waters. We found that the direction and rate of predation by pike on juvenile salmon varied by species and with stream flow and temperature, and that pike may switch to alternative prey once salmon are extirpated. Thus, changing freshwater processes may directly affect predation rates of pike on salmon, but not total consumption.
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K. Fitzgerald, L.H. Cheng, N. Boyles-Muehleck, R. Bellmore, J. Fellman, and J. Falke. 2023. Juvenile Coho Salmon growth patterns track biennial Pink Salmon spawning abundance fluctuations in a southeast Alaska watershed. National Meeting of the American Fisheries Society. 20-24 August, 2023,Grand Rapids, MI, USA.
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August 2023
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It is not well known whether adult salmon spawning abundance fluctuations confer disparate foraging and growth opportunities to stream-dwelling fish between years. We explored this hypothesis using a bioenergetic simulation paired with empirical field observations in a southeast Alaskan watershed that supports spawning salmon.
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Hermus, J.H., J.D. Muehlbauer, D.J. Rinella, V.R. von Biela, J.A. Falke. 2023. The effects of water temperature and heat stress on juvenile Chinook Oncorhynchus tshawytscha, and Coho Salmon Oncorhynchus kisutch growth in the Deshka River watershed. Mat-Su Salmon Science and Conservation Symposium, Palmer, Alaska, 13-14 November 2023.
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November 2023
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This presentation is an introduction to John Hermus’ master’s thesis. This project will analyze data from the Deshka River watershed, with the goal of understanding the effects of water temperature and heat stress on juvenile Chinook and Coho Salmon growth in the face of a changing climate.
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Fitzgerald, K., R. Bellmore, J. Fellman, C. Delbecq, and J. Falke. 2023. Stream hydrology and a salmon pulse subsidy shape juvenile salmonid foraging patterns in a southeast Alaska watershed. National Meeting of the American Fisheries Society. August 20 -24, 2023, Grand Rapids, MI, USA.
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August 2023
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Consumers capacity to exploit pulse subsidy resources may be influenced by antecedent environmental conditions such as stream flow. For juveniles of two salmonid species, we observed that consumption optima coincided with baseflow and high flow conditions, minima were observed during severe low-water and intermediate flow values, and interannual hydrologic variation shifted growth trajectories among years, potentially impacting access to pulse subsidies.
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Falke, J.A., Dunham, J.B., Rosenberger, A.E., Thurow, R.F., Dolloff, A., Howell, P.J., and W.C. Saunders. 2024. Standardized Sampling of Coldwater Fish in Wadeable Streams in North America. World Fisheries Congress, Seattle, WA. 3-9 March, 2024.
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March 2024
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In this presentation we describe our textbook chapter on standardized techniques for quantitative sampling of fishes in North American coldwater streams focused on backpack electrofishing, snorkeling, and redd count methods. We emphasize training, method validation, and obtaining unbiased measurements and estimates within sampling units as critical components of any coldwater stream standardized sampling program.
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Falke, J.A. and J.D. Paul. 2023. Landscape-scale prediction of freshwater habitat potential for Chinook Salmon (Oncorhynchus tshawytscha) across the Yukon and Kuskokwim River basins, Alaska. American Fisheries Society Annual Meeting, Grand Rapids, MI. 20 – 24 August 2023.
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August 2023
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Research into environmental factors involved in the decline of Yukon River Chinook Salmon stocks has exposed information gaps regarding fine-scale freshwater habitat quality known to influence population productivity. We developed spatially-explicit habitat suitability models for spawning and rearing life-stages based on fluvial geomorphic attributes, and are developing a decision support tool based on input from stakeholders tailored to the specific applications of this dataset.
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Falke, J.A. 2023. What is the Nevada Cooperative Fish & Wildlife Research Unit? Graduate Education, Collaborative Research, and Technical Assistance for Conservation of Great Basin Fish and Wildlife. Desert Fishes Council Annual Meeting. 15-18 November, 2023, Bishop, CA.
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November 2023
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Description of the Nevada Cooperative Fish and Wildlife Research Unit.
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