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Army Corps Release Sterile Carp in an Effort to Control Hydrilla

Wednesday, April 20, 2016
U.S. Army Corps of Engineers

In an ongoing effort to control the growth and spread of the invasive aquatic plant hydrilla in John H. Kerr Reservoir, the U.S. Army Corps of Engineers (USACE) released sterile grass carp (white amur) during the month of April. The grass carp preferentially feed on hydrilla over other aquatic plants and will provide a biological approach to help control this invasive species.

Hydrilla was initially detected in the reservoir in 1992 but was treated effectively and all but disappeared until 2008 when it was discovered in the Nutbush Creek section. Since then, the infestation has spread to other sections of the lake but a majority of the growth and spread has been within the Nutbush Creek Area and its tributaries.

USACE Conservation Biologist Billy Hoffer stated that “limited herbicide treatments have been completed the past few years by dock owners, USACE, and North Carolina State Parks.” Hoffer continued that “although herbicide treatments are effective on a small scale basis, introducing grass carp into the reservoir is more cost effective on a larger scale.”

The USACE initially stocked 13,300 sterile grass carp at three locations on Nutbush and Little Nutbush Creek in 2013. The Annual Hydrilla Survey has resulted in an additional 3,500 fish being stocked each subsequent year to offset mortality. The USACE along with fisheries biologists from North Carolina and Virginia, agreed that 15 fish per acre of hydrilla would provide adequate control. The fish which come from a hatchery in Arkansas, will be over 10 inches long and will be certified sterile by the U.S. Fish and Wildlife Service. Grass Carp stockings have become a popular biological control agent within the southeast and have had great success in other reservoirs in both North Carolina and Virginia.

Photo: Conservation Biologist Billy Hoffer helps to introduce sterile carp into the lake in order to control the growth and spread of the invasive hydrilla plant.