Meeting Abstract
In the 1980’s, invasive silver carp (Hypophthalmichthys molitrix) escaped from captivity within the United States and spread throughout the Mississippi River Drainage. Silver carp are planktivorous fish that severely disrupt ecosystems by competing with native filter feeders and altering the composition of the lowest trophic levels. They have gained additional notoriety due to their prodigious jumping behavior in response to moving watercraft, which field studies have shown can be induced by both water turbulence and sound. The triggering mechanism and the functional significance of the jumping behavior remain unknown. To better understand the behavior, 5 silver carp were filmed with a high speed camera mounted below an aquarium and stimulus latency, tail amplitude, tail frequency and swim velocity were monitored during jumping following a mechanical stimulus. The jumping behavior consistently followed a startle response, in which the peak amplitude of tail beats increased from roughly 1.28 cm during normal swimming to 1.60 cm and tail beat frequency increased threefold to 10 – 20 beats/second. Since results suggest jumping is initiated after the startle response, Mauthner neurons may be mediating the response.
