Midwest Fish & Wildlife Conference 2018

AUTHORS. Jared Wilson, University of Illinois, Illinois Natural History Survey; David H. Wahl, Illinois Natural History Survey

ABSTRACT. Shoaling behavior is one of many important strategies utilized by prey species to gather many types of information about their environment, particularly in regard to threat recognition.  By mimicking the response of an experienced individual, naïve individuals increase survivability.  Overlapping the niches of many native prey species, the widely distributed invasive Asian carp spend much of their early lives vulnerable to predation.  By shoaling in single species or mixed species groups, the survivability of these fishes may be increased.  The objective of this study was to evaluate the response of naïve juvenile Bighead Carp (H. nobilis) when grouped with experienced conspecific and heterospecific (N. chrysoleucas) shoal mates and exposed to a predator kairomone.  Groups were exposed to 20 mL of largemouth bass (M. salmoides) odor, and behavior was recorded before and after application.  Our results indicate a decrease in activity and nearest neighbor distance for naïve carp paired with conspecifics, however individuals paired with an experienced heterospecific displayed a response similar to the fright response of the heterospecific, indicating the alarm response of the Bighead carp may be somewhat plastic.  Future research is needed to determine if subsequent applications of predator kairomones influence the behavior of naïve individuals once the experienced individuals are removed.