Field Evaluation of Sex Pheromone Attractants to Control Asian Carp and Development of Protocols for Field Verification of Response

Our previous research has determined that invasive bighead and silver carp are responsive to conspecific pheromones.  They avoid alarm pheromones present in skin extracts as a means of avoiding predators, and they are attracted to chemicals released by groups of conspecifics as a means of maintaining schooling under turbid water conditions.  Sex pheromones are olfactory signals that mediate conspecific reproductive interactions.  The Asian carp sex pheromones are likely hormonal metabolites, as described in common carp and goldfish, which synchronize sexual readiness within the population and induce specific behaviors such as attraction, nest preparation, and spawning behaviors.  Physiological screening assays (electro-olfactograms) indicated very high sensitivity of the carp olfactory system for hormone metabolites associated with sex pheromones. Behavioral assays verified behavioral attraction to these hormone metabolites.  Proof-of-concept studies were initiated to determine if attractive sex pheromone production could be hormonally induced in females with the aim of using caged treated females as a source of attractive pheromone to aid in the capture of wild carp.  High concentrations of prostaglandin metabolites characteristic of carp pheromones were measured in water in which hormonally-induced female were held. Physiological olfactory assays confirmed that fish were highly sensitive to this stimulus.