Duke Energy intern Josh Bowen watches as 300 sterile grass carp are released April 23 into Lake Norman on the Davidson College Lake Campus. Grass carp are imported to the lake each year to control Hydrilla. About 10 years ago, it was discovered that the invasive weed was growing over about 400 acres of the lake, Lake Norman Marine Commission Executive Director Ron Shoultz said. In the program’s early years, several thousand grass carp were brought to Lake Norman to help manage the weed. The program is a collaborative effort between the North Carolina Aquatic Weed Council, the Lake Norman Marine Commission and the Charlotte-Mecklenburg Utility Department. (Melissa Gute/Herald Weekly photo)