Presentation Abstract

Landscape context is critical in estuary restoration planning and assessment due to the complexity and size of estuaries, and the unique attributes and cumulative effects of individual restoration projects. In addition, the diversity and mobility of estuarine species, in particular juvenile salmon, highlights the importance of landscape position given certain locations in the delta are less accessible to salmon. The Snohomish River delta has been the focus of major estuary restoration efforts in recent years and efforts could result in the largest cumulative estuary restoration action in Puget Sound. While several large projects have been initiated/competed in recent years, information to help prioritization and planning for future projects is currently lacking. We used a time series analysis of Chinook densities from 2011-2015 to assess general patterns in fish use and the effect of temperature and salinity through the outmigration period among the mainstem Snohomish River and the three primary distributaries. Two common trends in Chinook salmon density among the distributary and mainstem channels reflect patterns attributable to potential life history variation interpreted as an estuary rearing/residence component and general freshwater rearing (parr) outmigration. Furthermore, peak densities occurred earlier when above average temperatures were observed throughout the estuary. The differential patterns in Chinook density and the apparent influence of temperature may aid restoration evaluation, planning and prioritization aimed at increasing capacity for estuary rearing Chinook salmon throughout the delta and provide input regarding the potential effect of changing temperatures due to climate change.

Session Title

Salmon and their Habitats

Keywords

Chinook salmon, Estuary, Distribution, Restoration

Conference Track

SSE11: Species and Food Webs

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE11-535

Start Date

6-4-2018 8:45 AM

End Date

6-4-2018 9:00 AM

Type of Presentation

Oral

Contributing Repository

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

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

Share

COinS
 
Apr 6th, 8:45 AM Apr 6th, 9:00 AM

Evaluating common trends in Chinook density and the influence of temperature and salinity patterns among distributary channels in a large river estuary to aid evaluation, planning, and prioritization of restoration activities

Landscape context is critical in estuary restoration planning and assessment due to the complexity and size of estuaries, and the unique attributes and cumulative effects of individual restoration projects. In addition, the diversity and mobility of estuarine species, in particular juvenile salmon, highlights the importance of landscape position given certain locations in the delta are less accessible to salmon. The Snohomish River delta has been the focus of major estuary restoration efforts in recent years and efforts could result in the largest cumulative estuary restoration action in Puget Sound. While several large projects have been initiated/competed in recent years, information to help prioritization and planning for future projects is currently lacking. We used a time series analysis of Chinook densities from 2011-2015 to assess general patterns in fish use and the effect of temperature and salinity through the outmigration period among the mainstem Snohomish River and the three primary distributaries. Two common trends in Chinook salmon density among the distributary and mainstem channels reflect patterns attributable to potential life history variation interpreted as an estuary rearing/residence component and general freshwater rearing (parr) outmigration. Furthermore, peak densities occurred earlier when above average temperatures were observed throughout the estuary. The differential patterns in Chinook density and the apparent influence of temperature may aid restoration evaluation, planning and prioritization aimed at increasing capacity for estuary rearing Chinook salmon throughout the delta and provide input regarding the potential effect of changing temperatures due to climate change.