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For Release: Tuesday, May 28, 2013

Irondequoit Bay Fish Kill Linked to VHS

Anglers Encouraged to Help Prevent Spread of Virus

An ongoing fish kill in Irondequoit Bay, Monroe County, has been linked to viral hemorrhagic septicemia (VHS) virus, the NYS Department of Environmental Conservation (DEC) announced today. VHS is a fish disease and does not pose any threat to public health. To reduce the likelihood of spreading VHS in New York State, anglers and boaters are encouraged to abide by the following guidelines:

  • Do not transport fish from one body of water to another! Note that this practice is illegal without a DEC fish stocking permit;
  • Only release bait fish into the waterbody it was taken from. Bait purchased commercially should not be released into any body of water;
  • Do not dispose of fish carcasses or by-products in any body of water.
  • Remove all mud, aquatic plants and animals from all gear, boats, motors and trailers before leaving a body of water;
  • Drain your live well, bilge and bait tanks before leaving the water you are fishing or boating on. Anglers or boaters using any waterbody known to be infected with the VHS virus should disinfect their live wells and bait wells with a 10 percent chlorine/water solution (1 ¾ cups bleach per gallon of water). Rinse well to remove all residual chlorine;
  • Follow all fish health regulations and inform your friends about the fish health regulations.

Inspections by DEC aquatic biologists on April 25 and 29 indicate that nearly all of the dead and dying fish observed were gizzard shad, a medium-sized member of the herring family. White perch, yellow perch and freshwater drum were also observed. A sample of two gizzard shad, one yellow perch and one freshwater drum were collected and sent to Cornell University College of Veterinary Medicine's fish pathology laboratory. Results have shown that all three species of fish collected were infected with the VHS virus.

VHS is caused by a rhabdovirus (rod-shaped virus) that may affect fish of all size and age ranges. It does not pose any threat to human health, but is a serious disease of fresh and saltwater fish. VHS can cause hemorrhaging of fish tissue and can cause the death of infected fish. Once a fish is infected with VHS, there is no known cure. Not all infected fish develop the disease, but they can carry and spread the disease to other fish. It has caused fish mortalities ranging from a few fish to thousands. VHS has been in Lake Ontario for a sufficient period of time such that vulnerable fish species have been exposed to the virus, and have likely developed sufficient immune response that will reduce the likelihood of large-scale die-offs. The virus is, however, capable of mutating, which could again render fish populations vulnerable to disease outbreaks.

Mortality of gizzard shad in late winter and early spring is common and occurs cyclically, although it usually affects lower numbers of shad locally. This species is very sensitive to cold water temperatures and their inability to acclimate causes mortality at low temperatures. Gizzard shad are living near the northern edge of their range in the Great Lakes, making them especially susceptible to cold temperatures. Generally mild winters may have allowed their population to increase during recent years. In this particular case, late winter cold stress is suspected to have weakened this fish making them more susceptible to the VHS disease.

The VHS virus was linked to a large die-off of fish in Lake Ontario in 2005, and again in 2007. Since that time, it has been blamed for fish kills in Lake Michigan, Lake Huron, Lake St. Clair (MI), Lake Erie, the St. Lawrence River, Skaneateles Lake, Seneca-Cayuga Canal, Conesus Lake, and several inland lakes in Wisconsin and Michigan.

VHS can be spread from one waterbody to the next through a variety of means, usually involving the movement of infected fish. One method of inadvertently spreading VHS is by moving fish from one waterbody to another. VHS may also be spread through the discharge of water contaminated with the virus in live wells, bait wells, ballast tanks and bilge areas. DEC asks for the cooperation of ALL anglers and boaters to help prevent the spread of VHS.

If you witness a large number of dead or dying fish (usually 100 or more), please contact the nearest DEC regional office and ask for the Bureau of Fisheries. For more information about VHS, please see the DEC's web site. Questions about the Irondequoit Bay fish kill or VHS can be e-mailed to Bureau of Fisheries or by calling 585-226-5343.

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