This project monitors ecosystem response to dam removals on the Elwha River, Washington State. The Elwha Dam removal project is the largest project of its kind in the world and is the largest restorative action that has taken place in any Western U.S. Evolutionarily Significant Unit (ESU). Ecosystem response includes changes to aquatic habitat, the food web, and all aspects of the viable salmon parameters of listed and non-listed salmonid species. The project is based on the development and implementation of the Elwha Monitoring and Adaptive Management Guidelines (EMAM), which was developed as a collaborative effort between the Watershed Program at the NWFSC, the Lower Elwha Klallam Tribe (LEKT), the United States Department of Fish and Wildlife Service (USFWS), the United States Geologic Survey (USGS), the Washington Department of Fish and Wildlife (WDFW), and the National Park Service (NPS). We employ a variety of metrics to efficiently monitor ecosystem condition over space and time. This project will provide data to assess changes for the listed Elwha River populations (Chinook salmon and steelhead), and help determine whether those populations are improving, static, or declining. Such analyses are crucial to help inform future large-scale dam removals for multiple ESUs across the Western U.S. All relevant biological data.

This project monitors ecosystem response to dam removals on the Elwha River, Washington State. The Elwha Dam removal project is the largest project of its kind in the world and is the largest restorative action that has taken place in any Western U.S. Evolutionarily Significant Unit (ESU). Ecosystem response includes changes to aquatic habitat, the food web, and all aspects of the viable salmon parameters of listed and non-listed salmonid species. The project is based on the development and implementation of the Elwha Monitoring and Adaptive Management Guidelines (EMAM), which was developed as a collaborative effort between the Watershed Program at the NWFSC, the Lower Elwha Klallam Tribe (LEKT), the United States Department of Fish and Wildlife Service (USFWS), the United States Geologic Survey (USGS), the Washington Department of Fish and Wildlife (WDFW), and the National Park Service (NPS). We employ a variety of metrics to efficiently monitor ecosystem condition over space and time. This project will provide data to assess changes for the listed Elwha River populations (Chinook salmon and steelhead), and help determine whether those populations are improving, static, or declining. Such analyses are crucial to help inform future large-scale dam removals for multiple ESUs across the Western U.S. All relevant physical data.

Conduct captive brood stock gene rescue program for Elwha River odd-year class pink salmon. All fresh mortalities larger than 100 mm are sent to Fish Health for pathology. Autopsy data is maintained on their database.

We used snorkel surveys in the Elwha River, conducted in consecutive years before (2007, 2008) and after (2018, 2019) dam removal to assess changes in fish distribution and density. In total, we counted 54,616 Chinook Salmon, Bull Trout, Steelhead, and trout (Rainbow Trout and Coastal Cutthroat Trout combined) in 22 common reaches spanning 65 river kilometers. The occupancy of juvenile Chinook Salmon, Coho Salmon, and trout was also assessed following dam removal.

Conduct captive brood stock gene rescue program for Elwha River odd-year class pink salmon. Data is collected by broodyear on % survival to adult, % maturity as two year olds. Age of maturity data is available by sex.

Conduct captive brood stock gene rescue program for Elwha River odd-year class pink salmon. Data is collected by broodyear on % survival to adult, % maturity as two year olds. Age of maturity data is available by sex.

Conduct captive brood stock gene rescue program for Elwha River odd-year class pink salmon. Information on the number of smolts received into the program is maintained and summarized by year. The production of adults transferred to the Elwha Hatchery for restoration activities is also annually summarized.

Conduct captive brood stock gene rescue program for Elwha River odd-year class pink salmon. Raw data on rearing density, loading density, water temperature, ration, and feed size may be available. Raw data on administration of therapeutic drugs may be available.

Dam removal and other fish-barrier removal projects in western North America are assumed to boost freshwater productivity via the transport of marine-derived nutrients from recolonizing Pacific salmon (Oncorhynchus spp). In anticipation of the removal of two hydroelectric dams on the Elwha River in Washington State, we tested this hypothesis with a salmon carcass addition experiment. Our study was designed to examine how background nutrient dynamics and benthic foodwebs vary seasonally, and how these features respond to salmon subsidies. We conducted our experiment in six side channels of the Elwha River, each with a spatially paired reference and treatment reach. Each reach was sampled on multiple occasions from October 2007 to August 2008, before and after carcass placement. We evaluated nutrient limitation status, measured water chemistry, periphyton, benthic invertebrates, and juvenile rainbow trout (O. mykiss) response, and traced salmon-derived nutrient uptake using stable isotopes. Outside of winter, algal accrual was limited by both nitrogen and phosphorous and remained so even in the presence of salmon carcasses. One month after salmon addition, dissolved inorganic nitrogen levels doubled in treatment reaches. Two months after addition, benthic algal accrual was significantly elevated. We detected no changes in invertebrate or fish metrics, with the exception of 15N enrichment. Natural seasonal variability was greater than salmon effects for the majority of our response metrics. Yet seasonality and synchronicity of nutrient supply and demand are often overlooked in nutrient enhancement studies. Timing and magnitude of salmon-derived nitrogen uptake suggest that uptake of dissolved nutrients were favored over direct consumption of carcasses. The highest proportion of salmon-derived nitrogen was incorporated by herbivores (18–30%) and peaked 1–2 months after carcass addition. Peak nitrogen enrichment in predators (11–16%) occurred 2–3 months after addition. All taxa returned to background d15N levels by 7 months. Since this study was conducted, both dams on the Elwha River were removed over 2011-2014 to open over 90% of the basin to anadromous fishes. We anticipate that as the full portfolio of salmon species expand through the basin, nutrient supply and demand will become more balanced and positive feedback loops of reciprocal nutrient transfer reinforced. All datasets related to Elwha River carcass addition experiment. Includes physical habitat, chemical, and biological data.

Conduct captive brood stock gene rescue program for Elwha River odd-year class pink salmon. The fork length to the nearest mm and weight to the nearest gram of a subsample of fish is recorded on an approximately quarterly basis.