The U.S. Fish and Wildlife Service will apply lampricide to the Grand River to kill invasive sea lamprey larvae. The application will take place between April 20 and 30, depending on weather or stream conditions. The parasitic fish, which can kill up to 40 pounds of fish during their parasitic phase, are a major threat to the Great Lakes fishery. Infested tributaries must be treated regularly with lampricides to control their populations.