A review of the preference-avoidance responses of fishes to aquatic contaminants

Abstract

With the exception of cadmium, PCBs, malathion, and under some conditions, parathion, most other chemicals elicited avoidance responses (preferences responses in the case of mercury) at concentrations generally much less than LC50 levels. Chronic values for comparison are scarcer but, again, for some chemicals avoidance thresholds were below supposed safe levels. Some fish species responded sensitively to copper, zinc, nickel, and chlorine, whereas lead, PCBs, and malathion were not readily detected by those species. As noted earlier, pulp mill wastes were also effective at eliciting avoidance at subchronic concentrations. It is immediately apparent that no statistical correlation exists between those concentrations eliciting avoidance and those concentrations causing acute or chronic toxicity.