Hybridization in Bigheaded Carps and Its Impact on Their Invasion Success

In invasion biology, hybridization can often have a considerable impact on the invasion success and ecological impact of an invasive species.  Hybridization most often occurs between native and invasive species, which can result in declines in the native species and increased adaptation and/or fitness of the invasive species.  Hybridization can also help the invading species overcome low genetic diversity and founder effects.  However, hybridization between two exotic invasive species is rare, especially for animals, and so the results and impacts of such a hybridization event are relatively unknown.  Bighead Carp (Hypophthalmichthys nobilis) and Silver Carp (H. molitrix) co-occur across much of their native range, yet do not often hybridize.  However, hybridization is relatively common in many of the Midwestern rivers of North America where these species are highly invasive.  This study combines acoustic telemetry with spawning assessments and molecular work to assess the impacts of hybridization on the invasion success of bigheaded carps (Hypophthalmichthys spp.) in a North American river system, the Wabash River, Indiana.  Similarities and differences between hybrids and the parental types were assessed through total length, condition, length-weight regressions, home range size and the movements of adults as well spawned egg size and abundance