Localization of Substrate Vibrations by the Mottled Sculpin (Cottus bairdi)

Blinded Cottus bairdi respond to substrate vibrations from prey and artificial stimuli by placing the mandible on the substrate, turning toward the buried stimulus, moving toward it in a series of “hops,” and biting into the sand at the stimulus. In this study, the accuracy of the initial turning response to a “point” stimulus lo-29 cm away was determined and it was found that C. bairdi accurately turns toward the stimulus in its first hop after stimulus onset. Elimination of lateral line response by either streptomycin or Ca+* free water with Co+* (competitive inhibitor) destroys the ability to locate substrate vibrations, but the fish still respond to stimulus onset by placing the mandibkon the substrate. Placing the mandible on the vibrating substrate may allow transmission of the signal to the mandibular neuromasts, which are the largest neuromasts in this species. ECENT studies of the desert scorpion, Pururoctonus mesaensis (Veajovidae) (Brownell and Farley, 1979) and the lizard, Scincus scincus (Scincidae) (Hetherington, 1989) have shown an ability to locate prey from substrate vibrations. The present study shows similar ability in a benthic fish, the mottled sculpin (Cottus bairdi) (Cottidae). In Lake Michigan, mottled sculpins eat swimming prey from the water column and buried prey, such as burrowing amphipods, oligochaetes, and midge larvae (Hoekstra and Janssen, 1985). Untrained blinded (eye removal) sculpins locate artificially generated substrate vibrations and,respond by biting vigorously and swimming into the substrate (Hock; stra and Janssen, 1985). The primary aim of this study is to describe the response of C. bairdi to live prey and to determine its ability to turn toward an artificial vibrating stimulus buried in lake sand. The effect of pharmacological elimination of the lateral line system on the behavior is also described.