Analysis of dying largemouth bass collected by biologists from Lake Tenkiller has confirmed the presence of Largemouth Bass Virus (LMBV), a virus implicated in bass die-offs in six southeastern states since 1995. Samples collected in mid-August were sent to the U.S. Fish and Wildlife Service Pinetop Fish Health Center in Arizona for analysis.
According to Oklahoma Department of Wildlife Conservation fisheries biologists, reports of dying largemouth bass 16 inches or longer started in Lake Tenkiller in late July and have continued throughout August. With help from the Corps of Engineers, State Park employees and local anglers, biologists continue to investigate the extent and magnitude of the kill on one of the state's premier bass lakes.
"We've made several site visits covering most of the lake and have counted over 200 dead or dying fish since the first week in August," said Hutchie Weeks, northeast regional fisheries supervisor. "We've had unconfirmed reports of dead fish in the thousands. It's difficult to get actual numbers when such a large area is affected and the kill is prolonged over a long period," Weeks added. First documented in 1995, LMBV has been found in 12 southeastern states, but only Texas, Arkansas, South Carolina, Mississippi, and Louisiana have had fish kills attributed to the virus. Not all bass that have the virus die from the disease. In fact, most bass that carry LMBV appear completely normal. Where the virus has triggered the fatal disease, dying fish often swim near the surface and have trouble remaining upright. LMBV appears to attack the swim bladder causing bass to lose equilibrium. Some diseased fish may appear bloated. Adult bass two pounds or more seem to be more susceptible to the disease. Since die-offs have occurred from June through September, warm-water temperatures might play a factor in triggering an outbreak.
LMBV affects only cold-blooded animals and although researchers have found it in other bass and sunfish species like crappie, it has proven fatal only to largemouth bass. LMBV is not known to infect warm-blooded animals, including humans. Fish infected with the virus are safe to eat when properly cooked.
Thus far, no evidence has shown that LMBV has caused a long term problem or major impact on any fishery. Last summer, up to 4,000 largemouth bass reportedly died from LMBV on Lake Fork in Texas and other incidents have been reported from Lakes Sam Rayburn, Conroe and Toledo Bend (TX - LA).
Texas biologists report that comparative analysis of electrofishing surveys before and after these kills indicated no statistical decline in the bass fishery at Lake Fork.
"We're learning more and more about LMBV everyday, however there's still many unanswered questions," said Kim Erickson, chief of fisheries for the department. "Our crews will continue to monitor and investigate any reports of dead or dying fish in Tenkiller or any other Oklahoma reservoir, and we'll certainly be cooperating with other state and federal agencies in addressing the problem.
"We are hopeful that the die-off will run it course and be over like it has in other states. We'll be conducting follow-up surveys on Tenkiller to assess the impact but there is no known prevention or eradication measures that can be done to remove the virus from the population," said Erickson.
Although no specific solutions have been discovered, anglers may help minimize the spread of LMBV by doing the following: *Clean boats, trailers and live wells thoroughly between fishing trips to keep from transporting the virus from one body of water to another.
*Do not move fish or fish parts from one body of water to another. *Do not release live bait into a lake. *Handle bass as quickly and gently as possible if you intend to release them. *Stage tournaments during cooler weather to avoid stress on fish. *Report dead or dying fish to ODWC. *Educate other anglers about LMBV.