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Information contained in the spatial excitation pattern along arrayed sensors in the lateral line system of Lake Michigan mottled sculpin, as well as other surface-feeding fish and amphibians, is thought to play a fundamental role in guiding prey-orienting behaviors. However, the way in which prey location is encoded by the excitation pattern and used by the nervous system to direct orienting behaviors is largely unknown. In this study, we test the hypothesis that mottled sculpin use excitation peaks (local ‘hot spots’) to determine the somatotopic location of an artificial prey (vibrating sphere/dipole source) along the body surface. Dipole orientation (axis of sphere vibration re: long axis of the fish) is manipulated to produce excitatory peaks in different body locations without changing the actual sphere location. Our results show that orienting accuracy is largely independent of source orientation, but not source distance and that turning directions are not guided by local hot spots in the somatotopic activation pattern of the lateral line. [ABSTRACT FROM AUTHOR]

We compared prey-orienting and rheotactic behaviors in a fluvial (Coweeta Creek) and lacustrine (Lake Michigan) population of mottled sculpin. Blinded sculpin from both populations exhibited unconditioned, mechanosensory based rheotaxis to low velocity flows. Whereas Lake Michigan sculpin generally showed increasing levels of positive rheotaxis to increasing velocities, Coweeta Creek sculpin show varying levels of positive rheotaxis at low to intermediate velocities and often reduced positive rheotaxis or even negative rheotaxis at the highest velocities (12  cm  s -1 ). Blinded Lake Michigan, but not Coweeta Creek mottled sculpin exhibited an orienting response to a small (3  mm diameter) artificial prey (50  Hz vibrating sphere). In conclusion, the two populations differed in the strength and polarity of the rheotactic response at higher velocities and in their responsiveness to mechanosensory cues from epibenthic prey sources. These behavioral differences have most likely arisen from different learning experiences in different habitats and from the greater importance of visual cues to the Coweeta Creek mottled sculpin and mechanosensory cues to Lake Michigan mottled sculpin in the sensory guidance of orienting behaviors. [ABSTRACT FROM AUTHOR]