Invasive Species

 Exotic Fish Disease Found in New York Lakes

Dr. Paul R. Bowser, Cornell University
edited by Peter Landre, CCE Yates

Viral Hemorrhagic Septicemia Virus (VHS) is a dangerous fish pathogen first discovered in the Great Lakes in 2005. Fisheries managers are concerned the virus will infect a number of different fish species and will spread to other waters in the state, much like other exotic invaders such as zebra mussels. 

So far, the disease has killed muskellunge, freshwater drum, round gobies, smallmouth bass, walleyes and burbots. In addition, the virus has infected black crappies, bluegills, largemouth bass, pumpkinseed sunfish, rock bass, white bass, white perch, yellow perch, northern pike and brown bullheads. 

As of February 2007, the virus has been confirmed in fish from the St. Lawrence River, Lake Ontario, the Niagara River, Lake Erie, and Conesus Lake. The NYSDEC is currently testing for the infection in other bodies of water throughout the state. The World Animal Health Organization considers VHS to be a "very serious pathogen" because no treatment exists for this virus. Huge fish kills can occur where VHS strikes. The disease is believed to pose no threat to humans. 

We anticipate the spread of the disease will continue over the next few years, said Dr. Jim Casey, associate professor of virology at Cornell University. We fear there may be more widespread presence of the virus. According to Dr. Paul Bowser, a professor of aquatic animal medicine at Cornell University, "This is a new pathogen and for the first number of years 4, 5 or 10 years things are going to be pretty rough, then the animals will become more immune and resistant and the mortalities will decline." 

The primary symptom of VHS infected fish is bleeding. Other important signs include damage to the kidneys, liver, and spleen. Since these symptoms are common to many other fish diseases, it is not possible to diagnose a fish as being infected with VHS unless that fish undergoes a sophisticated laboratory evaluation. The picture is further complicated by the fact that fish that carry the virus often show no signs of disease. 

The only means to fight VHS is to prevent its spread. This hard fact has led to the development of regulations by the USDA-APHIS (the Department of Agriculture's Animal and Plant Health Inspection Service) and the NYSDEC that are designed to contain the spread of infected fish. 

To prevent the spread to other Finger Lakes, people must be willing to follow regulations and guidelines designed to limit the spread. The virus can be spread by the movement of infected fish (primary risk), or as a contaminant on boats, nets, fishing gear, live-well water, or bilge water. 

Boaters are strongly encouraged to drain, clean and disinfect with 10% chlorine solution live wells, bilges and bait tanks and thoroughly drying gear between trips. Since bait fish are thought to be the greatest risk of transferring the disease from lake to lake, ask your bait shop owner if his/her minnows have been tested and certified to be disease free. Never use uncertified minnows in waters different from their origin as this can spread the disease and is also illegal under the new regulations. 

For more information about VHS visit: http://search.dec.state.ny.us/query.html?qt=VHS&Search.x=33&Search.y=5




To Preserve and Protect Keuka Lake