Current control agents registered for use to control invasive or nuisance fish by the U.S. Environmental Protection Agency (EPA) are not selective, and when applied throughout the entire water column, expose native fishes to lethal levels of the control agent. Development of a microparticle delivery system filter-feeding bigheaded carps (bighead carp Hypophthalmichthys nobilis and silver carp H. molitrix) consume could reduce impacts to non-target native species by limiting their exposure to the control agents. Using technologies developed for aquaculture, pharmaceutical and agrochemical industries, USGS is developing and evaluating different microparticle formulations to identify those that may deliver biological or chemical control agents to control populations of bigheaded carps. Selecting the right formulation will require an in-depth understanding of the feeding habits, anatomical features that filter-feeding animals use to retain food particles (e.g. gill raker morphology), digestive physiology, and xenobiotic metabolism of native species and the bigheaded carps.
