Largemouth Bass Virus In West Virginia

WVDNR Fish Health Survey Discovers Presence of Largemouth Bass Virus in Four Lakes

            SOUTH CHARLESTON, W.Va. – Recent fish health surveys conducted by the West Virginia Division of Natural Resources revealed the presence of largemouth bass virus (LMBV) in four West Virginia lakes, according to Bret Preston, assistant chief of the Wildlife Resources Section.

            Surveys performed during the summer and early fall of 2011 were focused on monitoring overall fish health in water bodies where WVDNR staff collects broodstock for hatchery production. Several species of fish were collected from 10 water bodies and samples were sent to the U.S. Fish and Wildlife Service’s Lamar Fish Health Laboratory for analysis. 

            Virology and bacteriology results were negative for targeted pathogens except for LMBV at East Lynn (Wayne County), North Bend (Ritchie County), Stonewall Jackson (Lewis County), and Sutton (Braxton County) lakes.  Fish health surveys also were conducted at Mount Storm (Grant County) and Moncove (Monroe County) lakes and Little Kanawha (Wood County), Monongahela (Monongalia County), Tygart (Barbour County), and New (Summers County) rivers. 

            “Largemouth bass virus is a common pathogen found primarily in southern United States largemouth bass populations, but has been expanding throughout North America,” said Chris O’Bara, WVDNR fisheries research biologist.  “LMBV has not been linked to any human health concerns but, as always, fish should be properly prepared prior to eating.”

            Largemouth bass populations infected with LMBV have experienced summer die-offs, depressed growth, and less than optimal health condition. LMBV is more problematic during summertime and elevated stressful conditions. The spread of LMBV has been linked to increased stress, fish to fish contact , and movement of fish and water between water bodies.

            To minimize the spread of LMBV and all fish pathogens, WVDNR encourages anglers not to transfer any live fish or water between water bodies, handle all fish with care prior to release, reduce stressful conditions especially during warm water months, and properly clean and maintain all boats, live wells, and tackle.

                WVDNR staff will continue to monitor fish health statewide and expand the survey into several new water bodies in 2012, according to O’Bara.  Results of the 2011 survey, as well as future surveys, will be provided on the DNR website at www.wvdnr.gov.

**DNR**

Largemouth Bass Virus

Largemouth Bass Virus Detected in Virginia Reservoirs...


No impact to people; impacts to fish normally are short lived and fish populations recover



Largemouth bass virus (LMBV) is a disease that impacts several fish species but only appears to cause death in some largemouth bass. First discovered in Florida in 1991, LMBV spread throughout the southern United States and was responsible for a number of largemouth bass deaths in the late 1990's. However, in some reservoirs LMBV only led to a decrease in survival and growth rates. When those declines occur, anglers catch fewer quality-size (greater than three pounds) largemouth bass. The good news is that impacts from the virus outbreak are normally short lived and largemouth bass fisheries recover in about three years.



The Virginia Department of Game and Inland Fisheries (VDGIF) and the North Carolina Wildlife Resources Commission (NCWRC) tested several reservoirs between 2000 and 2003 with most either having no occurrence of LMBV or very slight infection rates. However, in a few reservoirs in North Carolina almost 40% of the largemouth bass tested were positive for LMBV. One of those systems was Shearon Harris Reservoir, which continues to support one of the best largemouth bass fisheries in the state.



Recent virus testing coordinated by VDGIF this past August revealed that LMBV was present in about 40% of the bass tested at John H. Kerr Reservoir/Buggs Island Lake and is responsible for the decline in the bass fishery. Largemouth bass from Briery Creek Lake and Sandy River Reservoir (Prince Edward County) were also tested and the virus was detected and confirmed. A small largemouth bass mortality event which occurred at Briery Creek Lake in late June, 2010, was most likely the result of LMBV in the population.



Due to the popularity of the largemouth bass fishery at Kerr Reservoir/Buggs Island Lake, anglers have expressed concerns about the LMBV spreading to other area reservoirs. However, some of the area reservoirs already contain LMBV and fish have likely built-up an immunity to the virus. For example, largemouth bass in Lake Gaston tested positive for LMBV in 2000. However, recent surveys at Lake Gaston indicate that the largemouth bass population is doing well. Nevertheless, anglers should follow the precautions listed below to limit the spread of LMBV.



FAQ:



Can we cure the disease? No, the virus will have to run its course and hopefully the fish will build up immunity to LMBV. So far, lakes affected by the disease in the southern U.S. have not experienced additional large LMBV outbreaks since the initial ones in the late 1990's.

Are there any risks to humans from the virus? No, fish are safe to eat and the water is safe for drinking water supply and recreation. This virus cannot be passed to humans.

What causes an outbreak of the virus? It is not fully understood what causes an outbreak of LMBV. It is likely that stressful conditions such as low reservoir levels, high water temperatures, or increased handling time make bass more susceptible to LMBV.

How can you tell if a largemouth bass that you've caught has the disease? There are very few external cues that the bass might have the disease. Fish that are very sick from the virus may appear bloated and swim erratically due to the impacts of the virus on the swim bladder.

How does the disease spread? Fish that come in close contact (like in a livewell) can easily infect one another. Transmission through the water and eating infected prey are also ways that the disease is spread.

What can anglers do?



Limit fishing, especially tournament fishing, to cooler months. Bass with LMBV are more likely to suffer mortality in the heat of the summer due to stress related to the high water temperatures. Paper tournaments without weigh-ins are always on option that tournaments can explore for summertime tournament fishing.

Cooling livewells with blocks of ice in summer months is highly recommended. But, do not decrease water temperature in livewells more than 20° F from reservoir water temperatures.

DO NOT transfer fish or fish parts from one body of water to another. This can spread the virus.

Land fish quickly and handle them gently to avoid exhaustion and capture stress. Return the fish quickly to the water if you do not plan to keep it.

Sterilize bilge pumps and livewells with a bleach solution to kill the virus. Studies have shown that the virus can survive in water in livewells up to seven days. About 1.5 fluid ounces of bleach added to one gallon of water (1% solution) sprayed on livewell surfaces will kill the virus. Let the bleach solution stand for 5 minutes, rinse thoroughly, and let air dry as chlorine bleach is toxic to fish.

Tournaments should adopt best handling practices at all events. Using release boats, resting stations with oxygen and/or recirculating water, and iced water are all important considerations when planning a tournament. Refer to the conservation pages of the TBF or BASS websites for more information on safe handling practices and tournament organization guidance.

For information contact:



Dan Michaelson

Virginia Department of Game and Inland Fisheries

Fisheries Biologist

434-392-9645

This information is from the Outdoor Report