Presentation Abstract
Over the past decade, monitoring surveys in the greater Seattle area have revealed anomalous behaviors among adult coho salmon returning to spawn in restored urban streams. Behaviors included erratic surface swimming, gaping, fin splaying, and loss of orientation and equilibrium. Affected fish died within hours, and female carcasses showed high rates (> 90%) of egg retention. This phenomenon was termed coho pre-spawn mortality (PSM). From 2002-2012, rates of coho PSM ranged from ~ 30-90% in monitored urban streams. The severity of PSM was closely associated with fall rain events. Samples from affected coho exhibited evidence of exposure to metals and petroleum hydrocarbons, both of which commonly originate from motor vehicles. Geospatial analyses point to urban land uses, impervious surfaces and specifically road density as being directly related to the levels of PSM across watersheds. This indirect evidence suggests that metals and PAHs may be causing PSM. Therefore, during the autumns of 2011 and 2012, we exposed adult coho recently returned to freshwater to various mixtures of PAHs and metals to simulate motor vehicle road runoff. The chemical cocktails targeted concentrations matching or exceeding those measured during storm events in urban streams. Exposures of up to 2 days to the PAH and metal mixtures did not produce PSM symptomology. The results suggest that while the specific contaminants in the simulated runoff mixtures cannot be ruled out as contributing factors for coho PSM, the tested mixtures alone were not sufficient to cause PSM symptomology.
Session Title
Session S-05B: Water Quality II
Conference Track
Toxics
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
1-5-2014 10:30 AM
End Date
1-5-2014 12:00 PM
Location
Room 608-609
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Coho salmon--Mortality--Washington (State)--Puget Sound; Urban runoff--Toxicology--Washington (State)--Puget Sound; Coho salmon--Effect of metals on--Washington (State)--Puget Sound; Coho salmon--Effect of water pollution on--Washington (State)--Puget Sound; Automobiles--Environmental aspects--Washington (State)--Puget Sound
Geographic Coverage
Salish Sea (B.C. and Wash.); Puget Sound (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
Included in
Symptoms of adult coho salmon pre-spawn mortality are not produced by exposures to artificial mixtures of metals and PAHs.
Room 608-609
Over the past decade, monitoring surveys in the greater Seattle area have revealed anomalous behaviors among adult coho salmon returning to spawn in restored urban streams. Behaviors included erratic surface swimming, gaping, fin splaying, and loss of orientation and equilibrium. Affected fish died within hours, and female carcasses showed high rates (> 90%) of egg retention. This phenomenon was termed coho pre-spawn mortality (PSM). From 2002-2012, rates of coho PSM ranged from ~ 30-90% in monitored urban streams. The severity of PSM was closely associated with fall rain events. Samples from affected coho exhibited evidence of exposure to metals and petroleum hydrocarbons, both of which commonly originate from motor vehicles. Geospatial analyses point to urban land uses, impervious surfaces and specifically road density as being directly related to the levels of PSM across watersheds. This indirect evidence suggests that metals and PAHs may be causing PSM. Therefore, during the autumns of 2011 and 2012, we exposed adult coho recently returned to freshwater to various mixtures of PAHs and metals to simulate motor vehicle road runoff. The chemical cocktails targeted concentrations matching or exceeding those measured during storm events in urban streams. Exposures of up to 2 days to the PAH and metal mixtures did not produce PSM symptomology. The results suggest that while the specific contaminants in the simulated runoff mixtures cannot be ruled out as contributing factors for coho PSM, the tested mixtures alone were not sufficient to cause PSM symptomology.
