Foraging and growth potential of juvenile Chinook Salmon after tidal restoration of a large river delta

Transactions of the American Fisheries Society
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Abstract

We evaluated whether restoring tidal flow to previously diked estuarine wetlands also restores foraging and growth opportunities for juvenile Chinook Salmon Oncorhynchus tshawytscha. Several studies have assessed the value of restored tidal wetlands for juvenile Pacific salmon Oncorhynchus spp., but few have used integrative measures of salmon performance, such as habitat-specific growth potential, to evaluate restoration. Our study took place in the Nisqually River delta, Washington, where recent dike removals restored tidal flow to 364 ha of marsh—the largest tidal marsh restoration project in the northwestern contiguous United States. We sampled fish assemblages, water temperatures, and juvenile Chinook Salmon diet composition and consumption rates in two restored and two reference tidal channels during a 3-year period after restoration; these data were used as inputs to a bioenergetics model to compare Chinook Salmon foraging performance and growth potential between the restored and reference channels. We found that foraging performance and growth potential of juvenile Chinook Salmon were similar between restored and reference tidal channels. However, Chinook Salmon densities were significantly lower in the restored channels than in the reference channels, and growth potential was more variable in the restored channels due to their more variable and warmer (2°C) water temperatures. These results indicate that some—but not all—ecosystem attributes that are important for juvenile Pacific salmon can recover rapidly after large-scale tidal marsh restoration.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Foraging and growth potential of juvenile Chinook Salmon after tidal restoration of a large river delta
Series title Transactions of the American Fisheries Society
DOI 10.1080/00028487.2014.945663
Volume 143
Issue 6
Year Published 2014
Language English
Publisher American Fisheries Society
Contributing office(s) Western Ecological Research Center
Description 15 p.
First page 1515
Last page 1529
Time Range Start 2010-04-01
Time Range End 2012-07-31
Country United States
State Washington
Other Geospatial Nisqually River delta
Online Only (Y/N) N
Additional Online Files (Y/N) N
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