Presentation Title

Landscape scale drivers and predictions of coho salmon spawner mortality across urban gradients in Puget Sound

Session Title

Decision support tools to support adaptive management of Salish Sea restoration efforts

Conference Track

Protection, Remediation and Restoration

Conference Name

Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)

Contributing Repository

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

Type of Presentation

Oral

Abstract

Since the late 1990s, urban stream surveys have shown that coho salmon spawners experience high rates (e.g., 40-90% across a total run) of pre-spawn mortality (PSM). Evidence to date suggests that toxic urban stormwater runoff is the likely causative agent. PSM at these high rates may threaten wild coho populations, particularly in urbanizing basins. We previously used survey data from a limited number of Seattle-area urban streams and found a close correlation between PSM and the degree of urbanization. These relationships were strengthened when rainfall patterns were qualitatively incorporated into the analysis.

To improve our analyses, we added spawner survey data from 45 monitoring sites, incorporated seasonal precipitation patterns, and used landscape indicators of urbanization that coincided temporally with monitoring data. Our approach identified the underlying gradients of urbanization related to PSM, which we used to predict PSM risk throughout the Puget Sound basin. The refined analyses captured a larger geographic area within Puget Sound and improved our understanding of the interplay between urbanization and climatic drivers of PSM. Our results are consistent with other studies that suggest motor vehicles are the likely source of a chemical mixture that washes off urban landscapes into coho spawning streams.

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.

Language

English

Format

application/pdf

Type

Text

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Landscape scale drivers and predictions of coho salmon spawner mortality across urban gradients in Puget Sound

2016SSEC

Since the late 1990s, urban stream surveys have shown that coho salmon spawners experience high rates (e.g., 40-90% across a total run) of pre-spawn mortality (PSM). Evidence to date suggests that toxic urban stormwater runoff is the likely causative agent. PSM at these high rates may threaten wild coho populations, particularly in urbanizing basins. We previously used survey data from a limited number of Seattle-area urban streams and found a close correlation between PSM and the degree of urbanization. These relationships were strengthened when rainfall patterns were qualitatively incorporated into the analysis.

To improve our analyses, we added spawner survey data from 45 monitoring sites, incorporated seasonal precipitation patterns, and used landscape indicators of urbanization that coincided temporally with monitoring data. Our approach identified the underlying gradients of urbanization related to PSM, which we used to predict PSM risk throughout the Puget Sound basin. The refined analyses captured a larger geographic area within Puget Sound and improved our understanding of the interplay between urbanization and climatic drivers of PSM. Our results are consistent with other studies that suggest motor vehicles are the likely source of a chemical mixture that washes off urban landscapes into coho spawning streams.