Identification of non-native populations and reconstruction of invasion routes in the Redbreast Sunfish Lepomis auritus

Human-mediated introductions of non-native species are expected to increase globally and threaten native biodiversity. Lepomis auritus (Redbreast Sunfish), a carnivorous freshwater fish native to rivers in eastern North America, has been introduced far outside of its native range due to its popularity in recreational fisheries. However, poor documentation of introductions and lack of thorough ichthyofaunal surveys before the mid-20th century have complicated our understanding of the establishment and spread of non-native L. auritus over the past 90 years, precluding effective management. We conducted phylogenomic analyses using ddRAD data from 197 specimens of L. auritus collected throughout the known geographic range of the species to reconstruct the introduction history of the species. Our protocols allow for the reconstruction of complicated introduction routes and reveal that L. auritus in Texas is the result of a single-source introduction from the Suwannee River, the population in the upper Tennessee River has two sources of introduction from the Savannah River and the northeastern rivers that drain into the Atlantic Ocean, and the populations in the middle Tennessee River and the Mobile River Basin have sources from the upper Tennessee River system and the Apalachicola River Basin. Ecological and evolutionary investigations of the non-native populations of L. auritus will broaden the understanding of invasion dynamics in species of Lepomis and other non-native freshwater fishes in North America. Our study provides critical information for the conservation of native populations and invasive management of non-native populations of L. auritus.