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Regional Back Ground
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Project 199102900 began in 1991 to provide some of the first biological data on the contemporary population of fall Chinook salmon Oncorhynchus tshawytscha in the Snake River basin that was eventually listed in 1992 under the Endangered Species Act as the Snake River fall Chinook salmon evolutionary significant unit (ESU). Up until 2018, the project was implemented cooperatively by staff of the U.S. Fish and Wildlife Service and the U.S. Geological Survey. In 2018, the USGS assumed primary sponsorship of the project. As in past years, the project continue to complement and be coordinated with existing Snake River fall Chinook salmon ESU projects including staff of Idaho Power Company, the Nez Perce Tribe Department of Fisheries Resources Management, National Oceanographic and Atmospheric Administration, University of Idaho, and Washington Department of Fish and Wildlife.

The 2008 Biological Opinion and RPA have received much attention from the resources management community in the Pacific Northwest.  Most recently it was reviewed by the Obama Administration.  This review led to an Adaptive Management Implementation Plan (AMIP).  A full review of the AMIP is beyond the scope of this back ground statement, but it builds on the 2008 Biological Opinion and parallels and supports the other regional actions outlined above.  The AMIP advocates collecting more data and improving analytic tools to better inform future adaptive management decision making.  It calls for enhanced research on salmon predators and invasive species including a determination of whether removals of smallmouth bass in areas of intense predation could reduce the mortality of juvenile salmonids.  It supports enhanced RM&E actions to fill data gaps including: adult status and trend monitoring, juvenile status and trend monitoring, and the development of expanded life-cycle and passage models.  Project staff will be actively involved in the AMIP process.

We will also summarize historical data and collect new data to make progress towards answering two questions posed in the Monitoring, Evaluation, Research and Reporting plan: (1) is the ESU abundant, diverse, productive, and spatially distributed; and (2) is the ESU responding to implemented actions as anticipated?  We recast these two questions as regional objectives: (1) increase the abundance, productivity, and spawning distribution of natural origin adults, and (2) increase the abundance and diversity of natural-origin subyearlings during early freshwater rearing and migration.  The success criteria for regional objective 1 will be: (1) an increased understanding of the anthropogenic, biological, and environmental factors that influenced historical and contemporary trends in adult abundance, (2) an increased understanding of how varying influential anthropogenic, biological, and environmental factors might facilitate meeting the minimum viability threshold, and (3) documentation of the status of escapement of natural-origin adults to the spawning areas relative to the explicit population level spatial structure criteria, and (4) support for expanded life-cycle and passage modeling.  The success criteria for objective 2 will be: (1) estimates of passage abundance for natural-origin fall Chinook salmon subyearlings at Lower Granite Dam during the spring, summer, and fall, (2) an increased understanding of the anthropogenic, biological, and environmental factors that influence trends in passage abundance, (3) an increased understanding of how varying influential anthropogenic, biological, and environmental factors might increase passage abundance of natural-origin fall Chinook salmon subyearlings, (4) an increased understanding of the effect of predation in riverine habitat on passage abundance of natural-origin fall Chinook salmon subyearlings, and (5) support for expanded life-cycle and passage models.

We will accomplish the regional objectives by accomplishing several scientific objectives each of which will produce final deliverables including models to support the AMIP process.


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Regional Objective 1 Final Deliverables
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Final deliverable 1A will be a set of models that provide a historical retrospective of adult abundance and spawning distribution that will rely on adult counts made without distinction of adult origin, but with redd counts made throughout the Snake River basin from 1947 to 2018. These models will accomplish the following scientific objectives: (1) describe the numerical trends in the adult counts, (2) describe the numerical and spatial trends in redd counts; (3) evaluate changes in the ability to use redd counts as accurate and precise predictors of adult counts, and (4) increase the understanding of how the numerical trends in the adult counts were influenced by anthropogenic, biological, and environmental change. In 2020, we will add to our existing adult data set to address these objectives. The models and continued analysis of adult productivity through empirical data collection and life-cycle modeling will help complete regional objective 1 success criterion 1.

Final deliverable 1B will be a second set of models that help to explain and predict increases in the abundance, productivity, and spawning distribution of natural origin adults by focusing on estimated counts of natural-origin adults at Lower Granite Dam from run construction and on redd counts made upstream of Lower Granite Reservoir after 1982 (or as early as possible depending on data availability).  It will accomplish the following scientific objectives: (1) increase the understanding of how the numerical trends in the estimated counts of natural-origin adults during 1983–2018 were influenced by anthropogenic, biological, and environmental change, (2) predict how varying influential anthropogenic, biological, and environmental factors might affect the status of natural-origin adults relative to the minimum viability threshold, and (3) predict the status of escapement of natural-origin adults to the spawning areas relative to the explicit population level spatial structure criteria.  Using the redd count data we collect in the Snake River and the basinwide redd data collected by our research group, we will strive to complete a journal manuscript describing the results before the end of 2020. The model and the manuscript will confirm completion of objective 1 success criteria 2 and 3.


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Regional Objective 2 Final Deliverables
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Final deliverable 2A will be set of models that help to explain and predict variation in passage abundance of natural-origin subyearlings at Lower Granite dam during 1992–2018. The scientific objectives will be to: (1) describe numerical trends in passage abundance of natural-origin fall Chinook salmon subyearlings estimated by reconstructing the run; (2) compare annual passage timing distributions calculated using different methods, (3) increase the understanding of how the numerical trends in passage abundance were associated with anthropogenic, biological, and environmental change, (4) use the results from scientific objectives 1 and 2 to predict how varying influential anthropogenic, biological, and environmental factors might increase abundance of natural-origin fall Chinook salmon subyearlings. By adding new PIT-tag data from our project and collected by our collaborators as it becomes available, we will strive to complete a journal manuscript describing the results before the end of 2020. The models and the manuscript will confirm completion of objective 2 success criteria 1, 2, and 3.

Final deliverable 2B will be a set of models that focus on predation by smallmouth bass in riverine rearing habitat along the lower Snake River during 1997–2016. The scientific objectives will be to: (1) estimate the abundance of smallmouth bass, (2) describe the diet of smallmouth bass, and (3) estimate subyearling loss to predation by smallmouth bass. We have made much progress toward completing this work since 2012. Efforts in 2020 will focus on producing a river-wide subyearling loss estimate due to predation that will be summarized in a report by 2021. The models and the report will confirm completion of objective 2 success criterion 4.