It’s interesting, from a pseudo-scientific standpoint, that Largemouth Bass Virus traveled across the country killing bass along almost the same east to west track that other environmental and ecological disasters moved in the latter parts of the 20th Century.
I’m not saying there’s a connection or a conspiracy or even a Commie plot. I’m just saying the demise of wild bobwhite quail, the spread of imported fire ants and the migration of Eurasian collared doves followed virtually the same trail, east coast to the west, sweeping across Texas before we knew what hit us.
Each of those events has had a lasting, though vastly different impact on our wildlife and fisheries landscape. Fire ants are here to stay. Quail are nearly gone. Collared doves have added something to the hunting experience.
Largemouth Bass Virus showed up in many lakes. It killed lots of fish in some, maybe none in others, and then it settled in as a routine part of the water systems in most of the state.
After fish in Sam Rayburn took the first known hit in 1998 and Lake Fork a year later, Texas Parks and Wildlife began a systematic search for the virus and found it in most places they looked. They also learned that heat seemed to be a factor in outbreaks but that there is pretty much nothing we can do except monitor and assess.
“There are no current LMBV outbreaks that I am aware of in state waters,” says Greg Southard at Texas Parks and Wildlife’s A.E. Wood Fish Hatchery in San Marcos. “The last confirmed LMBV in Texas occurred at Lake Timpson in 2008, which was considered to be a minor kill.
“Minor fish kills (fewer than 100 fish) have occurred at Lakes Bastrop (2002), Big Creek (2007) and Timpson (2008). Major fish kills occurred over a decade ago at Lake Sam Rayburn (1998) and in 1999 at Lakes Conroe, Toledo Bend, and Fork when LMBV was first detected in fish from state waters.”
The lakes hit hard by LMBV have seemed to recover quickly, replacing the virus’ main targets, which were older, larger bass. Lake Fork may have suffered more than most because the top-ranked big bass lake isn’t producing the sheer numbers of trophy fish it once did. But that’s just speculation. Nobody can say for sure why or if there’s any connection.
One thing we have learned, though, is that once a lake has been infected and had an outbreak of the virus, it doesn’t appear to suffer any further die-offs. “There is evidence that largemouth bass exposed to LMBV will form an antibody to the virus, which would provide immunity to future infection … a good reason as to why we don’t see repeat LMBV fish kills,” Southard says. “So it seems that once the virus encounters the population, some bass are lost but the majority of fish survive and are able to transmit that immunological advantage to their progeny.”
The virus was first found and identified in South Carolina in 1995 and quickly began a rapid westward movement that carried it to Texas by at least 1998. Of course, no one knows whether it was already here or how it got here. But TPWD set out to study it and determine at least some of our vulnerability to it, Southard says.
“A statewide survey was conducted in 2000-2001 to determine where the virus was so that fisheries biologists could manage the problem,” he says. “We took a proactive approach to stock those waters where the virus had not been found with fish from state hatcheries that were determined to be clean of the virus. By 2004, the number of LMBV-related fish kills had declined greatly and public concern dwindled.”
Southard says TPWD will continue to test and monitor hatchery fish for the virus and to stock only LMBV-free fingerlings in state waters. Beyond that, there’s not much TPWD can do about the virus to prevent its spread or stop any future outbreaks.