Field Notes - Bass Virus Found
The U.S. Fish and Wildlife Service identified largemouth bass virus during annual sampling this past summer of the Mississippi River downstream from the Twin Cities. It’s the first time the virus has been confirmed in Minnesota and Wisconsin waters. The virus was found in smallmouth bass taken from pool 3 (near Red Wing) as well as largemouth bass, smallmouth bass, white bass, and rock bass in pool 7 (southeast of Winona). Fish samples tested from pools 4 and 9 showed no sign of the virus.
The virus has killed largemouth bass in more than 24 locations nationwide. However, it does not kill entire largemouth bass populations. Surveys on lakes following a kill suggest fish populations remain within normal ranges.
Other members of the sunfish family known to become infected with the virus include spotted bass, Suwanee bass, bluegill, redbreast sunfish, white crappie, and black crappie. So far, the virus has proved fatal only to largemouth bass.
The Minnesota DNR Fish and Wildlife pathology laboratory has been testing fish for the virus for the past two years. Largemouth and smallmouth bass from state and private fish hatcheries will continue to be examined for the virus. No largemouth bass virus has been detected at the hatcheries or in Minnesota’s lakes.
Infected fish are safe to handle and eat. Largemouth bass virus does not affect humans or other warm-blooded animals. Its origin is unknown, but it is related to a virus found in frogs and other amphibians, and is nearly identical to a virus isolated in fish imported for the aquarium trade.
Anglers can help prevent the spread of this and other fish diseases, as well as the spread of exotic species, by taking these steps:
- • Never transport live fish and stock them in other waters without a DNR permit.
- • Never release aquatic animals from one water body into another.
- • Dispose of unwanted minnows and leeches on shore. Never release live bait of any kind.
- • Drain water from your boat motor, live well, bilge, and transom wells at the ramp access.
- • Remove any visible plants and animals from your boat and equipment before leaving any water body.
- • Wash and dry your boat and any equipment that normally gets wet to kill invisible exotics and pathogens between fishing trips.
Jason Abraham DNR staff writer