7759 - Laserfiche WebLink

Home Browse Search

integrate sensory inputs from olfactory receptors and signal detection of an odorant by performing ecologically relevant behaviors (e.g., predator avoidance or initiating searching behavior for food). Behavioral Assay The majority of behavioral studies involving copper and zinc have emphasized estimation of thresholds for toxicant avoidance or preference using previously unexposed fish. Lowest observed effect concentrations for avoidance range from 0.04 to 6.4 µg/L copper (Sprague 1964; Westlake et al. 1974; Folmar 1976; Hara 1981; Giattina et al. 1982), and 5.6 to 53 µg/L zinc (Sprague 1964; Sprague 1968; Black and Birge 1980). These studies assume that wild fish inhabit uncontaminated water and have the opportunity to avoid contaminant exposure. This assumption may be false for rivers occupied by Colorado squawfish where background concentrations of copper and zinc equal or exceed reported thresholds for avoidance for other fishes (Table 1). Studies in which fish were pre-exposed to copper or zinc, and then challenged with an odorant that elicits a characteristic response, have been conducted less frequently. Saucier et al. (1991) exposed rainbow trout (Oncorhynchus mykiss) to 22 µg/L copper for 37 to 41 weeks and observed that exposed fish lost their ability to discriminate their own rearing water from well water or water containing largemouth bass (Micropterus salmoides). Rehnberg and Schreck (1986) exposed coho salmon 14