Any one reading B.A.S.S. Times or any other magazine focusing on bass fishing recently has probably read or heard of the Largemouth Bass Virus (LMBV). First gaining notoriety in South Carolina’s Santee-Cooper Reservoir, where it was associated with a bass die-off in 1995, this virus has since been found in 17 other states, including Virginia.

Virginia, like many states throughout the Southeast, has begun testing for the presence of LMBV in some of the State’s top bass fishing waters. Using the U.S. Fish and Wildlife Service’s Fish Health Unit at Lamar, Pa, testing for the virus began in the summer of 2001. With bass in the neighboring states of North Carolina, Tennessee, and Kentucky testing positive for the virus, it was anticipated that Virginia waters would test positive as well, which was the case. However, the virus in Virginia appears to have a very low prevalence – in most infected waters only one fish in 60 was a carrier. Although the presence of this virus may appear troubling, its occurrence does not mean that all bass in the state are diseased, nor does it imply that they will ever show signs of illness. No fish kills involving only largemouth bass have been reported in the Commonwealth, indicating that LMBV has not been a problem to date.

LMBV is one of more than 100 viruses that affect fish, but not warm blooded animals. So, the virus is not a threat to humans. Although other fish (particularly in the sunfish family) can be carriers of LMBV, it has only been associated with mortality of largemouth bass. Outbreaks of disease generally occur under conditions that are stressful for fish, such as hot and dry weather, and the resulting die-offs mostly affect larger fish. However, these die-offs are infrequent events and no long term impacts have been documented as a result of fish kills associated with the virus. Bass populations impacted thus far have fully recovered within one or two years after the initial die-off.

Little is known about LMBV at this time, and scientists have little advice to offer. Those most familiar with LMBV, however, believe it will be no more than a component of natural selection in the ecosystems affected and that the virus will only cause minor and sporadic fish kills. Most fish carrying this virus appear normal. LMBV attacks the swim bladder of fish, giving them a bloated appearance. Diseased and dying bass appear to have trouble swimming or staying upright and will swim near the water surface. If you see unusual numbers of dead or dying bass, please contact the Virginia Department of Game and Inland Fisheries at (804) 367-0509, or the Virginia Department of Environmental Quality at (804) 527-5020.

Virginia waters testing positive for the virus include: Buggs Island, Claytor Lake, Lake Flannagan, South Holston Reservoir, Occoquan Reservoir, and tributary streams to the James and Chickahominy rivers. The mainstem of the James and Chickahominy rivers, Lake Anna, Lake Chesdin, Nottaway and Shenandoah rivers, Briery Creek, Smith Mountain Lake, and ponds at the King and Queen Fish Cultural Station, that are used for largemouth bass brood stock, all tested negative for the virus. Anglers can help minimize the potential impact and spread of this virus by doing the following:

• After each fishing trip, drain and dry all live wells, bilge pumps, and thoroughly clean boats, motors, trailers and other equipment that were exposed to lake or river water.
• Do not move fish or fish parts from one body of water to another. Do not release unused bait into the water.
• Help educate others about LMBV.
• More information can be obtained on LMBV at http://espn.go.com/outdoors/bassmaster/s/bass_conserv_launch.html
• For further information on Virginia’s LMBV testing, please feel free to contact Tom Gunter, Fisheries Biologist at (804) 752-5503.