Author

Michela Burla

Date

December 2009

Document Type

Dissertation

Degree Name

Ph.D.

Department

Dept. of Science & Engineering

Institution

Oregon Health & Science University

Abstract

Scientists have recently questioned the paradigm that has informed salmon recovery strategies in the Columbia River (CR) for the past century, which have proven ineffective to reverse the precipitous decline in salmon runs. Relying on hatcheries and technological fixes, the approach has failed to consider and understand the ecological processes that are needed to ensure the health of the overall ecosystem. A shift is, however , under way, that recognizes the continuum of marine, estuarine and riverine environments as critical to preserver the diversity of life history characteristics that enable salmon populations from the CR to withstand environmental fluctuations. By including the estuary-plume-shelf continuum, the capabilities of offered by the CORIE/SATURN coastal-margin observatory can help pursue some of the scientific questions posed by the paradigm shift needed for salmon recovery. CORIE/SATURN relies on 3D numerical models (SELFE and ELCIRC) to systematically simulate and understand baroclinic circulation in the CR estuary-plume-shelf system. Multi-year databases of simulations were used in this dissertation to: - study CR plume variability in multiple temporal scales (inter-annual, seasonal, and event scale), with systematic approach based upon a suite of integrative metrics, climatologies and anomalies of surface salinity, and a EOF analysis; - address the question of whether the intraseasonal variability in smolt-to-adult survival rates (SARs) for steelhead (Oncorhynchus mykiss) and the Snake River spring/summer Chinook salmon (O. tshawytscha) relates to the changes in the CR plume as the juvenile migrants enter the ocean; - investigate the impact of natural variability and anthropogenic change on estuarine physical habitat opportunity (PHO) for salmon. Duplicative realizations of the simulation databases and multiple skill scores were used to perform a comprehensive evaluation of the skill of the CORIE/SATURN modeling system to reproduce CR plume dynamics. The research afforded an improved understanding of the seasonal and interannual variabiliaty in the CR plume dynamics; the formation of a hypothesis for the role of the CR plume in the survival of steelhead; and insights relevant to salmon recovery and restoration strategies in the CR estuary

Identifier

doi:10.6083/M4NV9G67

Division

Div. of Environmental & Biomolecular Systems

School

School of Medicine

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