Great Lakes Fish Hit by Deadly Virus Outbreak
The U.S. Department of Agriculture has prohibited the importation of certain species of live fish from Ontario and Quebec into the United States because of an outbreak of viral hemorrhagic septicemia (VHS).
The emergency order from the department’s Animal and Plant Health Inspection Service (APHIS) also prohibits the interstate movement of the same species from the eight states bordering the Great Lakes–New York, Pennsylvania, Ohio, Michigan, Indiana, Illinois, Minnesota, and Wisconsin.
VHS is a destructive pathogen that produces internal hemorrhaging and death. The disease does not pose a risk to people, but it has been found to affect fish species previously not known to be susceptible, including bait fish species, coho salmon, and channel catfish.
Dead and diseased wild fish have been reported in Lakes Ontario, St. Clair, and Erie, as well as the St. Lawrence River. An outbreak also was reported last month in fish from New York’s Conesus Lake, a body of water in the Great Lakes watershed but without direct connection to the lower Great Lakes.
APHIS officials say they do not know how VHS arrived in the Great Lakes area. One theory is that the disease may have mutated from a marine form and become newly pathogenic to freshwater fish.
The agency will update as necessary new, potentially susceptible fish species affected by this emergency order to prevent the further spread of the disease.
Since spring 2005, fish die-offs attributed to VHS have occurred in Lake Ontario, Lake Erie, and Lake St. Clair. The die-offs have affected muskellunge, smallmouth bass, yellow perch, bluegill, crappie, gizzard shad, freshwater drum, round goby, and other fish species. VHS also has been detected in samples of walleye, white bass, and other species that were not part of a die-off.
