Description
Non-point source runoff from urban and agricultural areas contains pollutants such as pesticides
and dissolved metals that can impair the sensory biology of Pacific salmon. We are using a combination of neurophysiological and behavioral approaches to determine whether exposure to these compounds is sufficient to impair the sensory biology of coho and other salmonids. A focus of these studies is the salmon olfactory system. The salmon sense of smell is critical for behaviors such as homing, foraging, and predator avoidance. Sublethal impacts on olfactory function could reduce the chances of survival or reproduction of individual salmon and, therefore, are a concern for the survival of salmon populations within the Pacific Northwest. Recent research has focused on the impact of dissolved copper, a heavy metal common in urban runoff. Using electrical recordings from the nose, we are measuring the impact of exposure to low levels of dissolved copper on the ability of the olfactory system to detect natural odors. Using video analysis of swimming, we are also measuring the effect of copper on the ability of salmon to behaviorally react to natural odors. We have recently found that neurophysiological and behavioral responses to an alarm pheromone are reduced or eliminated by a short-term exposure (3 hours) to low levels of dissolved copper (< 10 µg/L; see video). Future experiments will evaluate the impact of copper on additional aspects of salmon olfactory biology such as homing and predator avoidance.
Recording olfactory responses (electro-olfactograms, EOGs) in an anaesthetized juvenile coho. Two glass microelectrodes record the electrical activity in the nose evoked by an odor delivered via a glass capillary tube.
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Investigators
David Baldwin, Jana Labenia, Barb French and Nat Scholz
Collaborators
Jason Sandahl and Jeffrey Jenkins, Oregon State University
Support
National Research Council Postdoctoral Associateship to David Baldwin
NOAA Coastal Storms Initiative
Relevant Publications/Presentations
EOGs evoked by the amino acid L-serine before and after exposure to 10 µg/L dissolved copper. The downward deflection of the trace indicates the magnitude of the olfactory response.
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Baldwin, D.H. and Scholz, N.L. (2005). The electro-olfactogram: an in vivo measure of peripheral olfactory function and sublethal neurotoxicity in fish. In: Techniques in Aquatic Toxicology, Volume 2. GK Ostrander (ed.), CRC Press, Inc. Boca Raton, FL. Accepted.
Sandahl, J.F., Baldwin, D.H., Jenkins, J.J. and Scholz, N.L. (2004). Odor-evoked field potentials as indicators of sublethal neurotoxicity in juvenile coho exposed to copper, chlorpyrifos, and esfenvalerate. Canadian Journal of Fisheries and Aquatic Sciences 61 (3): 404-413.
Baldwin, D.H., Sandahl, J.F., Jenkins, J.J. and Scholz, N.L. (2005).Comparative thresholds for acetylcholinesterase inhibition and behavioral impairmentin coho salmon exposed to chlorpyrifos. Proceedings of the Society of Environmental Toxicology and Chemistry's 4th World Congress, Portland, OR. Oral Presentation.
Baldwin, D.H., Sandahl, J.F., Labenia, J.S. and Scholz, N.L. (2003). Sublethal effects of copper on coho salmon: Impacts on nonoverlapping receptor pathways in the peripheral olfactory nervous system. Environmental Toxicology and Chemistry 22 (10): 2266-2274.
Scholz, N.L., Sandahl, J.F., Labenia, J.S. and Baldwin, D.H. (2003). The neuro-ethology of coho salmon exposed to copper. Proceedings of the Society of Environmental Toxicology and Chemistry's 24th Annual Meeting, Austin, TX. Oral presentation.
Baldwin, D.H., Sandahl, J.F., Labenia, J.S. and Scholz, N.L. (2003). Sublethal effects of copper on olfaction and olfactory-mediated behaviors in juvenile coho salmon. Proceedings of the Georgia Basin/Puget Sound Research Conference 2003, Vancouver, BC, Canada. Poster presentation.
Scholz, N.L., Baldwin, D.H., Sandahl, J. and Collier, T.K. (2003) Neuro-physiological measures of sublethal toxicity in Pacific salmon. Pollutant Responses in Marine Organisms, 12th International Symposium, Safety Harbor, FL. Oral presentation.
Sandahl, J.F., Baldwin, D.H., Scholz, N.L. and Jenkins, J.J. (2002) Electrophysiological measures of copper neurotoxicity in coho salmon. Abstracts of papers of the American Chemical Society 224:U103-U103, Part 1. Winner, Best Postdoctoral Poster Presentation.
Popular Media
"Poisoning the imperiled: Three decades after DDT was banned, pesticides still take a toll on the nation's most vulnerable species", National Wildlife, Dec./Jan. 2004.
"When it rains, it pours pollutants into the waters", Seattle Post-Intelligencer, Nov. 20, 2002.
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