Fishes live in an aquatic medium that is rich in potential chemical cues. Soluble chemical products from various parts of a fish's body are known to trigger many forms of social and symbiotic behavior. Fish anesthetics that are commonly used for laboratory procedures and to capture fish in the field have long been rumored to have a negative effect on fishes' sense of smell. Limited research on one common anesthetic produced conflicting results. There have been no studies of the effects of other commonly used anesthetics or of any chemical at concentrations commonly used for field collections. Many fish behaviorists could be using test subjects that are deprived of a significant portion of their normal stimulus input. This study will provide an initial indication of the effects of the four most common anesthetics at the strongest concentrations normally used. The fright reaction of the goby, Asterropteryx semipunctatus, will be used as a test system. This reaction can be released, with about equal probability and intensity, by a chemical cue and a visual cue. Thus, fish that show impaired responsiveness to chemical cues can be tested for responsiveness to visual cues to distinguish any general effect on responsiveness from specific impairment of the chemical senses.
