Rapid growth in the early marine period improves the marine survival of Chinook salmon (Oncorhynchus tshawytscha) in Puget Sound, Washington

Canadian Journal of Fisheries and Aquatic Sciences
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Abstract

We examined the effect of early marine entry timing and body size on the marine (smolt-to-adult) survival of Puget Sound Chinook salmon (Oncorhynchus tshawytscha). We used data from coded wire tag release groups of hatchery Chinook salmon to test whether hatchery release date, release size, and size in offshore waters in July and September influenced marine survival. Marine survival was most strongly related to the average body size in July, with larger sizes associated with higher survivals. This relationship was consistent over multiple years (1997–2002), suggesting that mortality after July is strongly size-dependent. Release size and date only slightly improved this relationship, whereas size in September showed little relationship to marine survival. Specifically, fish that experienced the highest marine survivals were released before 25 May and were larger than 17 g (or 120 mm fork length) by July. Our findings highlight the importance of local conditions in Puget Sound (Washington, USA) during the spring and summer, and suggest that declines in marine survival since the 1980s may have been caused by reductions in the quality of feeding and growing conditions during early marine life.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Rapid growth in the early marine period improves the marine survival of Chinook salmon (Oncorhynchus tshawytscha) in Puget Sound, Washington
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/F10-144
Volume 68
Issue 2
Year Published 2011
Language English
Publisher NRC Research Press
Publisher location Reston, VA
Contributing office(s) Washington Cooperative Fish and Wildlife Research Unit
Description 9 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Canadian Journal of Fisheries and Aquatic Sciences
First page 232
Last page 240
Country United States
State Washington
Other Geospatial Puget Sound