MENSINGER, A.F.*; PALMER, L.M.; University of Minnesota Duluth and Marine Biological Laboratory; University of Minnesota Duluth and Marine Biological Laboratory: Detection of free swimming prey via the lateral line in the toadfish, Opsanus tau

Inductive neural telemetry was used to record from microwire electrodes chronically implanted into the anterior lateral line nerve of the toadfish, Opsanus tau . The lateral line of the toadfish was stimulated by the natural swimming movements of a prey fish (Fundulus heteroclitus) and the corresponding neural activity quantified. Both spontaneously active and silent afferent fibers experienced an increase in neural firing as the prey approached the lateral line. Activity was evoked when the prey fish approached to within 8 to 10 cm of the neuromast, with increases in nerve firing rates directly correlated with diminishing distance. Thus, adult toadfish (28 cm sl) were only able to detect mobile prey that were within a 1/3 of their body length. Lateral line afferent fibers did not become habituated to respiratory activity and were not inhibited during prey strikes. The results indicate that the range of the lateral line is less than 1/3 of toadfish standard length and probably does not provide feedback during predatory strikes.