Salish Sea Coho Salmon Declines – The Problem is not in Freshwater
Presentation Abstract
The Salish Sea Marine Survival Program is based on the assumption that factors operating in the marine waters of the Salish Sea are responsible for declining numbers of adult salmon returning to freshwater. In order to evaluate this assumption, one needs to consider the possibility that conditions outside the Salish Sea may be responsible, whether these exist in marine waters outside the Salish Sea, or in freshwater. Zimmerman et al. (Mar Coastal Fish 7:116–134, 2015) demonstrated that coho salmon smolt survivals within the Salish Sea declined during the period of study (1977-2010 ocean entry years), while those of reference populations outside the Salish Sea did not. The current study considers the possibility that declining adult returns may be the result of factors operating in freshwater. Data assembled for naturally spawning populations on both sides of the Can/US border were examined. Freshwater (spawner to smolt) survivals were highly variable but showed little evidence of consistent declines over time. Although the conservation of naturally spawning salmon requires the maintenance of suitable freshwater ecosystems, there is little evidence that declining coho salmon returns to the Salish Sea are the result of factors operating exclusively in fresh water.
Session Title
The Salish Sea Marine Survival Project- Novel Approaches, Project Status and Key Findings
Conference Track
Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Start Date
2016 12:00 AM
End Date
2016 12:00 AM
Location
2016SSEC
Type of Presentation
Oral
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Coho salmon--Monitoring--Salish Sea (B.C. and Wash.); Coho salmon--Research--Salish Sea (B.C. and Wash.); Endangered species--Estimates--Salish Sea (B.C. and Wash.); Coho salmon--Conservation--Salish Sea (B.C. and Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Salish Sea Coho Salmon Declines – The Problem is not in Freshwater
2016SSEC
The Salish Sea Marine Survival Program is based on the assumption that factors operating in the marine waters of the Salish Sea are responsible for declining numbers of adult salmon returning to freshwater. In order to evaluate this assumption, one needs to consider the possibility that conditions outside the Salish Sea may be responsible, whether these exist in marine waters outside the Salish Sea, or in freshwater. Zimmerman et al. (Mar Coastal Fish 7:116–134, 2015) demonstrated that coho salmon smolt survivals within the Salish Sea declined during the period of study (1977-2010 ocean entry years), while those of reference populations outside the Salish Sea did not. The current study considers the possibility that declining adult returns may be the result of factors operating in freshwater. Data assembled for naturally spawning populations on both sides of the Can/US border were examined. Freshwater (spawner to smolt) survivals were highly variable but showed little evidence of consistent declines over time. Although the conservation of naturally spawning salmon requires the maintenance of suitable freshwater ecosystems, there is little evidence that declining coho salmon returns to the Salish Sea are the result of factors operating exclusively in fresh water.
