Bighead and Silver Carp are planktivorous fish species that have invaded many aquatic systems throughout the Midwestern United States. Management of Bighead and Silver carp in the upper Illinois River has used an electric fish barrier and intensive contractual harvest. Since 2010, approximately 2,267 metric tons of Bighead and Silver Carp have been removed. Limited information is available on how removal has impacted native fish populations such as planktivorous Gizzard Shad which are also an important prey species. Long Term Electrofishing data were analyzed to determine how Gizzard Shad condition has changed since the commencement of Asian Carp removal efforts. We analyzed Gizzard Shad relative weight among three periods (pre-establishment, post-establishment, and removal) using a 2-way ANOVA, with the upper Illinois River as the treatment group and the lower Illinois River as the control group. Gizzard Shad condition decreased in the upper and lower river when Asian Carp invaded, but has increased in the upper river since contractual removal began. However, Gizzard Shad condition continued to decrease in the lower river, where no contractual removal occurred. This information provides support for current upper Illinois River removal efforts, and we encourage managers in other invaded basins to investigate similar control efforts.
|Original language||English (US)|
|Title of host publication||AFS - 147th Annual Meeting of the American Fisheries Society, August 20-24, 2017, Tampa, Florida|
|State||Published - 2017|