Identifying Critical Periods of Growth and Mortality in Pacific Salmon and Deciphering Underlying Mechanisms
Presentation Abstract
Size-selective mortality (SSM) is a significant force regulating recruitment of salmon. The life stage(s) and habitat(s) in which SSM occurs can vary among species, stocks, and life history strategies. Moreover, the relationship between juvenile growth and survival is unclear for most salmon stocks. The first marine growth season is commonly regarded as a critical period for growth and survival. For ESA-listed Puget Sound Chinook salmon, preliminary studies suggest that: at least one critical period occurs during the first marine growth season; growth is limited more by food supply than energetic quality of prey or thermal regime; and higher growth and survival rates correspond with higher contributions of key prey like crab larvae.
We can identify critical periods using scales to create growth histories of a juvenile cohort sampled serially at successive life stages throughout its first marine growth season. Divergences in growth trajectories indicate reduced contributions of smaller members to subsequent life stages. These divergences indicate critical periods of growth and survival and the magnitude of SSM. We can diagnose factors affecting growth during critical periods through bioenergetics modeling simulations linked to directed sampling of diet, growth and environmental conditions. This approach could improve run forecasting and focus restoration efforts.
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)
Chinook salmon--Size--Washington (State)--Puget Sound; Chinook salmon--Mortality--Washington (State)--Puget Sound
Geographic Coverage
Salish Sea (B.C. and Wash.); Puget Sound (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
Identifying Critical Periods of Growth and Mortality in Pacific Salmon and Deciphering Underlying Mechanisms
2016SSEC
Size-selective mortality (SSM) is a significant force regulating recruitment of salmon. The life stage(s) and habitat(s) in which SSM occurs can vary among species, stocks, and life history strategies. Moreover, the relationship between juvenile growth and survival is unclear for most salmon stocks. The first marine growth season is commonly regarded as a critical period for growth and survival. For ESA-listed Puget Sound Chinook salmon, preliminary studies suggest that: at least one critical period occurs during the first marine growth season; growth is limited more by food supply than energetic quality of prey or thermal regime; and higher growth and survival rates correspond with higher contributions of key prey like crab larvae.
We can identify critical periods using scales to create growth histories of a juvenile cohort sampled serially at successive life stages throughout its first marine growth season. Divergences in growth trajectories indicate reduced contributions of smaller members to subsequent life stages. These divergences indicate critical periods of growth and survival and the magnitude of SSM. We can diagnose factors affecting growth during critical periods through bioenergetics modeling simulations linked to directed sampling of diet, growth and environmental conditions. This approach could improve run forecasting and focus restoration efforts.
