Tennessee Wildlife Resources Agency

TWRA's Region 4 - East Tennessee

Reservoir Fisheries Management Program

Largemouth Bass Virus

October 15, 2001 TWRA News Release:
"Largemouth Bass Virus Update"

Largemouth Bass Virus (LMBV) is one of more than 100 naturally occurring viruses that affect fish but not warm-blooded animals. Its origin is unknown, but it is related to a virus found in frogs and other amphibians and nearly identical to a virus isolated in fish imported to the U.S. for the aquarium trade. Although the virus apparently can be carried by other fish species, to date it has produced disease (death) only in largemouth bass. Scientists do not know how the virus is transmitted or how it is activated into a fatal disease.

LMBV was first discovered following a fish kill on Santee-Cooper Reservoir in South Carolina in 1995. Since then, fish kills attributed to LMBV have been confirmed in nearly 20 locations throughout the South and in Lake George on the Indiana-Michigan border. Thus far however, there has not been a fish kill attributed to LMBV in Tennessee. However, it has been found in Tennessee.

Since often the virus can exist in bass without showing signs of illness, some fish might be infected without showing signs of illness. Some scientists believe that "stressed" bass may be more likely to die of the disease. Along with hot weather, stress factors can include poor water quality and frequent handling by anglers.

Due to the economic importance and popularity of largemouth bass, universities, private groups, and federal and state agencies, including the Tennessee Wildlife Resources Agency, are working hard to learn more about the virus. As a result of the interest and concern about LMBV, the U.S. Fish & Wildlife Service has given top priority for 2001 Sportfish Restoration Grants to four studies that focus on the virus. Tennessee is one of several southeastern states that has participated in LMBV research for the past 3 years. The State will continue to participate in the new studies that will be conducted in 2001 by Mississippi State University, Auburn University, Louisiana State University, and the U.S. Fish & Wildlife's Warm Springs Fish Health Center in Georgia.

Throughout the South, LMBV has been found in nearly every large body of water. In Tennessee, the virus has been identified in several reservoirs including Cherokee, Watts Bar, Chickamauga, Barkley, Woods, Douglas, Norris, Percy Priest, and Old Hickory as well as a TWRA Family Fishing Lake at Williamsport. The percentage of occurrence ranged from 6.7% to 46.7% in various bodies of water in 2000, however, the percentage showed an overall decrease in 2001. As stated earlier, even though the virus has been found extensively in Tennessee waters, it has not been attributed as a cause for any major fish kills to date.

The Bass Anglers Sportsman Society (B.A.S.S.) has sponsored and chaired meetings in 2000 and 2001 to bring state agency managers and researchers together. Plans have already been made for another meeting in 2002. More information will be related after the next meeting.


Indiana DNR 2005 publication pdf (153 k)