Abstract Title

Session S-05B: Water Quality II

Keywords

Toxics

Location

Room 608-609

Start Date

1-5-2014 10:30 AM

End Date

1-5-2014 12:00 PM

Description

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.

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May 1st, 10:30 AM May 1st, 12:00 PM

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.