Examining release-smolt and smolt-to-adult survival rates of spring Chinook salmon (Oncorhynchus tshawytscha) from the Willamette River
department or school: Science, Faculty of
department or school: Oceans and Fisheries, Institute for the
data provider: DSpace
degree campus: UBCV
creator: Hicks, Delaney
issued: 2025-10-16T18:52:46Z
issued: 2025
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: This thesis investigated juvenile freshwater and smolt-to-adult survival (ÏSAS) rates of threatened Upper Willamette River spring-run Chinook salmon (Oncorhynchus tshawytscha) and other spring- and summer-run Chinook salmon stocks across the Columbia River Basin. In Chapter Two, I analyzed Passive Integrated Transponder (PIT) tag data from 143 releases between 2002 and 2016 to estimate ÏSAS and release-smolt survival (ÏRSS) rates for Upper Willamette River spring-run Chinook salmon. I used a Bayesian Cormack-Jolly-Seber model with a minimum design configuration that included two detection locations: one for juvenile smolts before entry to the Columbia River estuary and one for adults on their return to the Willamette River. Sensitivity analysis results found a minimal effect of prior choice on model output results. Estimates of ÏSAS were consistently below the 2% recovery benchmark for the Columbia River Basin. Additionally, ÏRSS through river segments varied across Willamette River sub-basins, with the lowest estimates observed from release locations requiring longer migrations through multiple dams. In Chapter Three, I used published estimates of ÏSAS from the Snake, Middle Columbia, and Upper Columbia River and evaluated survival trends across these and the Willamette River. Common shared year effects revealed interannual variation; however, when separated, trends were not uniform across all regions, albeit with higher uncertainty. Univariate covariate analyses revealed negative associations that did not overlap with zero between ÏSAS estimates and the abundance of pink salmon in the Northeast Pacific Ocean, with adjusted R² values ranging from 0.02 to 0.11 across regions. Additionally, the Pacific Decadal Oscillation and El Niño-Southern Oscillation were linked to reduced survival, while the North Pacific Gyre Oscillation showed positive associations. Although these drivers showed the same associations with survival across all regions, their relative importanc…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/92639
note: Examining release-smolt and smolt-to-adult survival rates of spring Chinook salmon (Oncorhynchus tshawytscha) from the Willamette River by Delaney Hicks B.Sc., Dalhousie University, 2023 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Oceans and Fisheries) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) October 2025 © Delaney Hicks, 2025 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Examining release-smolt and smolt-to-adult survival rates of spring Chinook salmon (Oncorhynchus tshawytscha) from the Willamette River submitted by Delaney Hicks in partial fulfillment of the requirements for the degree of Master of Science in Oceans and Fisheries Examining Committee: Dr. Murdoch McAllister, Associate Professor, Institute for the Oceans and Fisheries, UBC Supervisor Dr. Tom Porteus, Independent Contractor, UBC Supervisory Committee Member Dr. Brian Hunt, Associate Professor, Institute for the Oceans and Fisheries, UBC Supervisory Committee Member Dr. Andrew Trites, Professor, Institute for the Oceans and Fisheries, UBC Additional Examiner iii Abstract This thesis investigated juvenile freshwater and smolt-to-adult survival (ÏSAS) rates of threatened Upper Willamette River spring-run Chinook salmon (Oncorhynchus tshawytscha) and other spring- and summer-run Chinook salmon stocks across the Columbia River Basin. In Chapter Two, I analyzed Passive Integrated Transponder (PIT) tag data from 143 releases between 2002 and 2016 to estimate ÏSAS and release-smolt survival (ÏRSS) rates for Upper Willamette River spring-run Chinook salmon. I used a Bayesian Cormack-Jolly-Seber model with a minimum design configuration that included two detection locations: one for juvenile smolts before entry to the Columbia River estuary and one for adults on their return to the Wi…
has type: Thesis/Dissertation
date issued: 2025-11
is shown at: 10.14288/1.0450466
language: eng
degree discipline: Oceans and Fisheries
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: McAllister, M. K
type: Text
identifier URI: http://hdl.handle.net/2429/92639