Assessing Bigheaded Carp on the Southeastern Leading Edge of Their North American Invasion

The invasive Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix (collectively referred to as Bigheaded Carp) were introduced to the U.S. in the 1970s to control noxious algae blooms in poly-aquiculture. In the lower reaches of the Tennessee River and Cumberland River systems, Bigheaded Carp were systematically sampled seasonally using multiple gears. Nearly 11,000 m of experimental gill nets captured 289 adult Silver Carp and 5 Bighead Carp.  Hoop nets (n = 96) captured only 2 Silver Carp and 2 Bighead Carp.  Twenty-six hours of boat mounted electrofishing collected 121 adult and 200 young-of-year (YOY) Silver Carp.  Cast nets (n = 600 throws) captured 15 YOY Silver Carp.  Adult Silver Carp in Lake Barkley and Kentucky Lake were similarly robust, and more robust than Silver Carp below Barkley Dam, suggesting food resources and habitat are ideal in those reservoirs.  Some YOY Silver Carp were collected 180 and 110 river kilometers upstream in Kentucky Lake and Lake Barkley, respectively, and are presumed to be the first evidence of natural reproduction in those reservoirs or their tributaries.  Continued research will describe abundance, age and growth, and recruitment mechanisms of Bigheaded Carp on the southeastern leading edge of their North American invasion.