Although laboratory analysis of healthy largemouth bass recently collected from Grand, Hudson and Ft. Gibson lakes indicates the presence of Largemouth Bass Virus (LMBV), Wildlife Department fisheries biologists do not expect any significant impacts on the bass populations in those lakes.
The fish, all of which were collected by electrofishing and appeared healthy, were sent to the U.S. Fish and Wildlife Service Pinetop Fish Health Center in Arizona for analysis. Angler reports of dead largemouth bass at Ft. Gibson and Grand lakes led fisheries personnel to have the bass tested for LMBV. "The Largemouth Bass Virus has been found in 12 southeastern states and Michigan, but to date there is little evidence that it has caused long-term problems or major impacts to bass populations," said Kim Erickson, fisheries chief for the Department. "Obviously we all are concerned when we see large numbers of dying and dead fish, but most bass that carry LMBV appear completely normal. Bass showing external secondary infections such as sores, abrasions or patches of fungus do not necessarily have the virus. Also, not all bass that have the virus die from the disease.
"It is important to stress that other states, like Texas, having much larger kills than we have seen in Oklahoma, now report that fishing is back to normal and the bass populations have rebounded."
Erickson added that LMBV has been implicated in bass die-offs in six southeastern states since 1995, and was recently confirmed in Lake Tenkiller bass in mid-August. 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.
Adult bass 14 inches or longer seem to be more susceptible to the disease.
One characteristic of LMBV-infected bass is they appear to lose equilibrium.
Where the virus has triggered the fatal disease, fish may appear bloated and can have trouble remaining upright. Fisheries biologists are learning more and more about LMBV everyday, but many questions about the disease remain unanswered. Stress from high water temperatures or excessive handling appears to be involved in triggering the disease, but biologists aren't certain exactly how the process occurs. Gene Gilliland, senior biologist at the Department's Fisheries Research Lab in Norman, added that several bass tournament groups (including Champion, Skeeter, Cobra, OK B.A.S.S. Federation) have voluntarily implemented procedures to reduce handling stress during fishing tournaments or have decided to suspend tournament activities during hot summer months.
Gilliland said the agency hopes to educate other tournament organizers and anglers in general to minimize the effects of handling stress, especially during critical times of the year. Follow-up sampling of Lake Tenkiller revealed the continued presence of LMBV in largemouth and smallmouth bass, but not in spotted bass. Erickson added that once established, LMBV appears to maintain a presence in the lake or reservoir, although fatalities decline.
"Research continues, but to date there is no known prevention or eradication measures that can be done to remove the virus from the population," he said. "We will certainly continue to monitor and investigate any reports of dead or dying fish in any of our state's reservoirs and will seek input from anglers who witness bass die offs."
Although no specific solutions have been discovered, anglers may help minimize the spread of LMBV by doing the following: *Clean boats and trailers thoroughly and drain live wells and bilges between fishing trips to avoid transporting the virus from one body of water to another. *Do not move fish or fish parts from one body of water to another. *Handle bass as quickly and gently as possible if you intend to release them. *Avoid holding tournaments during hot summer months to avoid stress on fish.
*Report dead or dying fish to ODWC. *Educate other anglers about LMBV.