PARENT SESSION

PW09 Pesticide I

8:00 AM - Wednesday

(PW166A) Neurobehavioral indicators of sublethal toxicity in juvenile coho salmon exposed to mixtures of anticholinesterase insecticides.

Laetz, C¹, French, B¹, Labenia, J¹, Baldwin, D¹, Scholz, N¹, ¹ NOAA Fisheries, Northwest Fisheries Science Center, Seattle, WA, USA

ABSTRACT- In the western United States, organophosphate and carbamate insecticides frequently co-occur in surface waters that provide habitat for salmonids. These pesticides share a common mechanism of action in that they inhibit acetylcholinesterase (AChE) activity in the fish nervous system. We have previously shown that mixtures of organophosphate and carbamate insecticides are dose-additive in terms of inhibiting salmon AChE activity in vitro. The goal of this study was to assess brain AChE inhibition in coho salmon exposed in vivo (96h) to individual pesticides (chlorpyrifos, malathion, ehoprop, carbaryl and carbofuran) and to binary pesticides mixtures. Moreover, brain AChE activity was compared to spontaneous swimming and feeding behaviors in individual fish using a computer-assisted three-dimensional data acquisition system. For individual pesticides, we observed AChE inhibition and reductions in motor behavior at low, environmentally relevant concentrations (<0.1 gl⁻¹). Thus, this is a promising approach to evaluate the functional relationship between AChE inhibition and salmon behavior across a variety of combinatorial insecticide exposures.

Key words: acetylcholinesterase, pesticides, salmon, behavior