Freshwater growth can provide a survival advantage to Interior Columbia River spring Chinook salmon after ocean entry

• DOI: 10.3354/meps14069
• Publication Date: 2022-05-09T09:57:16Z
• Authors: CR Norrie; CA Morgan; BJ Burke; LA Weitkamp; JA Miller
• Keywords: Chinook wind

ABSTRACT: A prerequisite to effectively managing fish populations is understand what factors and processes, including predation changing environments, affect the survival of individuals. In anadromous fishes, transition from freshwater marine habitats considered a critical period regulating population abundance due high variable mortality rates. During this period, conditions experienced in may influence size- growth-selective ocean. To determine if or occurred juvenile Interior Columbia River spring Chinook salmon Oncorhynchus tshawytscha as they migrated through Lower Estuary (LCRE) during early residence, we examined 2 cohorts years with differing (2016 2017). We reconstructed size growth individual otoliths compared these attributes caught at 4 sites LCRE those ocean off Oregon Washington. observed evidence 2017 but not 2016. Specifically, 2017, when overall was lower, individuals grew significantly faster than estuary. Given that had resided for an average 30 d, results indicate soon after entry. The finding impact adds growing body processes occurring both prior entry species.