Fish Diseases

Fish information


Viral Hemorrhagic Septicemia

Special Notice: VHS found in Lake Superior

A Cornell University research team’s recent finding of traces of the Viral Hemorrhagic Septicemia virus (VHS) in fish inhabiting Wisconsin and Michigan waters of Lake Superior is yet another reminder that anglers and boaters play an increasingly important role in preventing the spread of this fish virus and invasive exotic species.

Lake Superior is a potential gateway for VHS to enter Minnesota. Minnesota DNR has taken steps to prepare for this with changes in fisheries management activities, surveillance and legislation. With the possible entry of VHS into Minnesota waters of Lake Superior and other parts of the state, it is incumbent upon all users of the state's waters to remember to follow existing requirements:

Assuming all users of Lake Superior follow preventive measures as those listed above, no additional changes for recreational or commercial fishermen are likely at this time. However, smelt and baitfish like smelt taken from Lake Superior or its tributaries must be labeled as such and may not be used for bait in any other waters of the state.

Cause of disease:

Virus - extremely serious viral disease of fresh and saltwater fish

What does it look like?

At a low level of infection, fish might not display any symptoms. As the infection becomes greater, however, fish will display widespread hemorrhages (bleeding) throughout body surface (eye, skin and fins) and within the internal organs (swim bladder, intestine, kidney etc). Because of the bleeding, gills and liver might appear pale. Sick fish will often be listless, swim in circles, and are frequently observed at the surface of the water.


NOTE: Confirming VHS infection requires sophisticated laboratory testing. A diagnosis cannot be made based solely on observation because many different diseases of fish have very similar symptoms.

For more information, download the VHS flyer pdf

Viral Hemorrhagic Septicemia (VHS) Viral Hemorrhagic Septicemia (VHS)

Fish species affected:

To date, VHS has caused large-scale mortality in

VHS has also been confirmed in smaller fish kills in

Species known to carry VHS virus include (The disease has not killed any of these species to date.)

How does the disease spread between waters?

Where has the disease been found?

The disease has been found in Lake Huron, Lake St. Clair, Lake Erie, Lake Ontario, Lake Michigan, Lake Superior and the St. Lawrence River in New York. The virus has also been detected in several inland lakes including Budd Lake in Michigan and Lake Winnebago in Wisconsin. The Minnesota Department of Natural Resources is actively monitoring and testing for the VHS virus. So far the virus has not been detected in the inland waters of Minnesota.

If you would like to find out the most recent VHS infected sites call the DNR Pathology Lab at 651-259-5096.

Is it safe to eat?

The virus does not have any impact on humans, through direct contact or via fish consumption.

How can I prevent the spread?

Do not move live fish between waterbodies. DISPOSE of unwanted baitfish and fish parts in the trash.

Do not move any water between waterbodies. DRAIN water from boat, motor, bilge, livewells and bait containers before
leaving the water access.

SPRAY, DRY boat, trailer, and recreational equipment, especially after leaving known VHS infected waters.

If you catch a suspected diseased fish:

If you observe a fish kill: