North American Black Carp population genetics and related invasion dynamics : supplemental dataset

Objective: Black Carp (Mylopharyngodon piceus) are a spreading invasive species in the Mississippi River basin of North America that threaten native molluscan species, including numerous imperiled freshwater mussels and snails. Effective characterization of Black Carp population genetic patterns within this range should provide important insights related to breeding and dispersal that may be employed in developing monitoring and management programs. Methods: We assayed a set of 16 microsatellite DNA loci to assess population genetic attributes of Black Carp throughout their currently invaded North American range, estimate genetic differentiation among “populations” derived from geographic clustering of Black Carp captures and “clusters” identified through statistical clustering of individual genotypes, and reconstruct pedigrees for estimates of effective numbers of breeders and identification of likely full siblings. The dispersion of likely full siblings across the species range was then used to infer trends in dispersal distance. Results: North American Black Carp exhibited robust genetic diversity (mean AR ranging from 6.81 – 7.1 among geographically-delineated populations), with indications of potentially low to moderate inbreeding (mean GIS = 0.147; mean HO = 0.607). Population genetic differentiation was significant, but weak among geographically delineated populations (FCT = 0.015) and subpopulations (FST = 0.011). Concordantly, spatially unconstrained genotype clustering resulted in multiple best K clusters solutions, all of which had clusters comprised of individuals from many different, often distant capture locales. A significant, but weak isolation by distance pattern was also observed (r = 0.057). Simulations indicated that the loci we employed could predict full sibling dyads with > 99% precision, though under some extreme reproductive scenarios poor prediction sensitivity could result in many true full sibling pairs being “missed” (identified as half siblings or unrelated). The frequency of occurrence of full siblings decreased with increasing distance between individuals, but pairs of Black Carp from some dyads were captured separately at locations separated by hundreds of river kilometers (maximum detected distance of approximately 1,300 river km). Conclusion: North American Black Carp are genetically well-mixed and appear to disperse widely. Local control of Black Carp populations may need to account for the species apparent capacity to recolonize areas, even from long distances. There are some indications that reproductive output is highly unbalanced among breeding Black Carp. If reproductive success is positively skewed by age and size, as in some other fish, North American Black Carp numbers may increase relatively rapidly as earlier generation fish continue to mature and grow.