Genetic structure and multiple paternity in invasive Red Swamp Crayfish in southeastern Michigan, USA
Authors: Nicole Adams 1; Jared Homola 2; John Robinson 1; Kim Scribner 1
Affiliations: 1) Michigan State University, East Lansing, Michigan, USA; 2) U.S. Geological Survey, Wisconsin Cooperative Fishery Research Unit, Stevens Point, Wisconsin, USA
Keywords: Ecological & conservation genetics
The Red Swamp Crayfish, Procambarus clarkii, is a prolific invader that has successfully colonized every continent except for Australia and Antarctica. Native to the Mississippi River Basin, the southeastern United States and northern Mexico, P. clarkii was first detected in southeastern Michigan in 2017. Following detection, extensive state and local resources have been expended to eradicate established populations and minimize further spread of this species. Using genetic tools we sought to characterize founding history, levels and direction of gene flow, demographic history, and the reproductive biology of P. clarkii in Michigan waterbodies to inform management practices. RAD capture (RAPTURE) sequencing produced 580 million paired reads across 1100 individuals from 22 infested waterbodies. Using 842 individuals from 20 locations that successfully passed our filtering criteria, we found that samples clustered largely based on geography. Even within short distances we found evidence for genetic differentiation among sampled waterbodies. We assigned parentage to offspring sampled from egg or larva-bearing females. Employing likelihood-based pedigree reconstruction methods, we found that a single female could mate with 2-6 potential males. The estimated number of breeding adults varied between waterbodies. Additional collected samples are being characterized to look at source-sink founding population dynamics and landscape barriers to gene flow. Understanding how P. clarkii colonize vacant waterbodies across heterogeneous and heavily human-impacted environments and characterizing fundamental aspects of their reproductive biology are critical for eradication and prevention of further spread.