RWO257: using life cycle models to investigate climate change impacts on yukon river salmon populationsproject period: 09 15 2023 - 12 31 2024PROJECT abstract: the yukon river basin drains 833,000 KM2…

RWO257: using life cycle models to investigate climate change impacts on yukon river salmon populationsproject period: 09 15 2023 - 12 31 2024PROJECT abstract: the yukon river basin drains 833,000 KM2 across canada and alaska and supports valuable subsistence, commercial and sport fisheries for chinook and summer and fall chum salmon. Chinook and summer chum salmon migrate into the river from early june to mid-july at which point the fall chum salmon run begins and lasts through early september. Chinook salmon spawn in tributaries throughout alaska and canada and approximately half of the run migrates to canadian tributaries. Important chinook salmon tributaries in alaska include the chena and salcha rivers. Summer chum salmon spawn in the lower 700 miles of the yukon river and use tributaries of the tanana and koyukuk rivers fall chum salmon migrate to spawning habitats in the upper basin, mostly in canada.tributary habitats used for migration, spawning, and rearing have diverse hydrologic inputs including glaciers, snow, rain, and groundwater, which drives variation in freshwater habitat characteristics important to salmon such as the timing and magnitude of peakflows, magnitude of summer flows, and summer stream temperatures. A flow regime classification for the yukon basin is currently nearing completion (strohm ET AL. In prep) recipient will use the classification to characterize diversity of streamflow characteristics for important spawning tributaries identified for this project.project will include chinook and summer and fall chum salmon populations that spawn in tributaries of the alaska portion of the yukon river basin and as such, experience different environmental conditions across their freshwater life stages. The life cycle model requires spawner abundance, physical habitat, stream temperature, and streamflow information to develop a baseline scenario prior to initiating scenarios of changing hydrologic or thermal regimes. Spawner abundance information is available for populations that spawn in tributaries with escapement monitoring conducted by the alaska department of fish and game (ADF g) or the U.S. Fish and wildlife service (USFWS). Modeled daily streamflows from the global flood awareness system are available from 1 january 1979 until near real time and have been validated using a global network of over 1800 river observation stations (harrigan ET AL. 2020). Graduate student r. Shaftel will be completing a stream temperature model for the yukon river stream network that will be leveraged as an input to the life cycle modeling proposed for this project. Physical habitat information required for model inputs such as flooding effects on redds or calculating juvenile salmon densities is available for the alaska portion of the yukon river stream network. Across the alaska portion of the yukon river basin, spawning tributaries used by salmon include glacial- and snowmelt-FED rivers that differ in hydrologic and thermal regimes and timing of habitat use by different species. As such, large variations are expected in how different salmon populations experience similar climatic drivers in the future. Activities to be performed - 1) develop life cycle model parameters specific to chinook and chum salmon populations in the yukon basin.2) simulate scenarios of warming and increased precipitation using life cycle models. Deliverables and expected outcomes -1) PHD student dissertation chapter and peer-reviewed PUBLICATION2) associated data and model framework archived online intended beneficiary(IES) -yukon river basin state, federal, and tribal fisheries managers and decision makers subrecipient activities, if known or specified at the time of award -n a