Abstract
A new bioassay for assessing the behavioral responses of aquatic animals to chemical stimulants is described. The assay combines an octagonal fluviarium, capable of providing up to eight discrete plumes of treated water, with a video-based data acquisition system and with statistical and ethological descriptors of the behavior. Behavioral responses of zebra fish to various concentrations of alanine, copper and copper-alanine mixtures are presented. Groups of four fish were most responsive to alanine. Groups of two, six and eight fish were significantly less responsive than either groups of four fish or single fish, but were not significantly different from each other. These results are discussed in terms of social facilitation, social interference, conflict inhibition, leader-follower associations and "optimal" group size. The behavior of zebra fish encountering 0.1 and 0.01 mg liter⁻¹ (ppm) copper was similar, although there were significantly fewer entries into the plume of 0.1 ppm copper. Significant avoidance of both concentrations of copper was indicated by all statistical descriptors. Ethologically, the most extreme avoidance response was observed in these fish at both concentrations. Although a detection response was observed, no significant avoidance by zebra fish of 0.001 ppm copper was found. Responses to this concentration of copper were not significantly different from the responses of control fish. Five mixtures of copper and alanine were examined for their behavior-altering effects. The most important results, ecologically, were for the alanine +0.001 ppm copper mixtures. A concentration of a pollutant not eliciting statistically detectable avoidance by itself (i.e., 0.001 ppm copper) inhibits previously-observed exploratory feeding behavior released by 10⁻³ and 10⁻⁴ M alanine. It is hypothesized that this phenomenon is due either to masking of alanine by copper through competition at the receptor site, complexing of copper with alanine (thus decreasing the effective concentration of alanine available for detection by the fish) and/or by altering the "chemical search image" of zebra fish for alanine or alanine-containing food items.
Steele, Craig William (1986). Responses of zebra fish, Brachydanio rerio, to behavior-altering chemicals. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -16982.