An Integrated Approach to Using YY Technology and Mechanical Control Methods for Invasive Fish Control
Nonnative fishes have substantial impacts on native fishes through competition and predation. Targeted means to remove nonnative fishes where they become pests is warranted. Advancing technology shows promise in manipulating the sex of fishes using hormones to produce Trojan sex chromosome carriers (i.e., YY males) that will spawn with existing fishes and over time, reduce, and even eliminate their populations. While YY males have been developed for several different species, efforts to develop YY males of some of the most damaging invasive fishes in the southwestern United States have not been established. We examined the feasibility of producing Trojan sex chromosome carriers of a common, short-lived invasive nonnative species of the southwestern United States, the Red Shiner Cyprinella lutrensis. Further, we are examined the feasibility of the initial steps in production of Trojan sex chromosome carriers of a common long-lived invasive nonnative species to the southwestern United States, the green sunfish Lepomis cyanellus. We were successful at developing genetic sex identification markers that could be used to separate Red Shiner by sex, but we were unsuccessful at developing such identification markers for Green Sunfish. Laboratory facilities were constructed and rearing and treating of fishes with hormones were performed. Laboratory rearing methods for these species were developed and published. Hormone treatments were successfully conducted. Changes in fish anatomy during hormone application were studied. Production of Trojan YY male Red Shiner was successful, and the first specimens were produced fall 2022. A dissertation and further publications regarding this research were completed, and one other is in preparation.