Presentation Abstract

Size-selective mortality (SSM) is a significant force regulating recruitment at multiple stage during the life cycle of anadromous salmon, but the early marine life stages are consistently implicated as critical periods for growth and survival which influence SSM. The life stage(s) and habitat(s) when and where SSM is imposed can vary considerably among species, stocks, and life history strategies, and the relationship between size, growth, and condition in freshwater and marine life stages to overall life cycle survival is unclear for most stocks of salmon. Starting in Spring 2014, we will initiate a field sampling program is 4 Puget Sound watersheds that methodically tracks the timing, duration, and relative abundance of juvenile Chinook salmon at hatchery release, river outmigration (smolt traps), rearing in estuarine delta (tidal channel traps) nearshore marine (beach seines) and offshore marine habitats (purse seining and midwater trawling) of Puget Sound from April through October. The timing and relative magnitude of SSM will be determined by serial sampling of size distributions over a progression of life stages using both direct measurements of body size and back-calculated estimates from scales or otoliths. Disproportionate reductions in the contribution of smaller members to subsequent life stages, especially to adult returns, can be used to determine the timing and magnitude of SSM and identify critical periods of growth and survival. We will then diagnose which factors most affect growth during critical periods through bioenergetics modeling simulations that are linked to directed sampling of diet, growth and environmental conditions. This approach could potentially improve run forecasting and focus restoration efforts.

Session Title

Session S-06D: Marine Survival of Salmon and Steelhead: the Salish Sea Marine Survival Project

Conference Track

Species and Food Webs

Conference Name

Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)

Document Type

Event

Start Date

1-5-2014 1:30 PM

End Date

1-5-2014 3:00 PM

Location

Room 611-612

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

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

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May 1st, 1:30 PM May 1st, 3:00 PM

Marine Survival of Puget Sound Chinook salmon-New studies on size-selective mortality and critical growth periods

Room 611-612

Size-selective mortality (SSM) is a significant force regulating recruitment at multiple stage during the life cycle of anadromous salmon, but the early marine life stages are consistently implicated as critical periods for growth and survival which influence SSM. The life stage(s) and habitat(s) when and where SSM is imposed can vary considerably among species, stocks, and life history strategies, and the relationship between size, growth, and condition in freshwater and marine life stages to overall life cycle survival is unclear for most stocks of salmon. Starting in Spring 2014, we will initiate a field sampling program is 4 Puget Sound watersheds that methodically tracks the timing, duration, and relative abundance of juvenile Chinook salmon at hatchery release, river outmigration (smolt traps), rearing in estuarine delta (tidal channel traps) nearshore marine (beach seines) and offshore marine habitats (purse seining and midwater trawling) of Puget Sound from April through October. The timing and relative magnitude of SSM will be determined by serial sampling of size distributions over a progression of life stages using both direct measurements of body size and back-calculated estimates from scales or otoliths. Disproportionate reductions in the contribution of smaller members to subsequent life stages, especially to adult returns, can be used to determine the timing and magnitude of SSM and identify critical periods of growth and survival. We will then diagnose which factors most affect growth during critical periods through bioenergetics modeling simulations that are linked to directed sampling of diet, growth and environmental conditions. This approach could potentially improve run forecasting and focus restoration efforts.