Virus takes toll on largemouth bass at Buggs Island Lake Oct 3, 2019 17:24:05 GMT
Post by Ghost Comanche©® on Oct 3, 2019 17:24:05 GMT
Virus takes toll on largemouth bass at Buggs Island Lake
by Tom McLaughlin | October 4, 2019
A virus is killing the big bass of Buggs Island Lake, and it may take several years for the disease to run its course and the fishery to fully recover its full health.
Wildlife biologists discovered the presence of largemouth bass virus (LMBV) in Buggs Island Lake after hearing earlier this year from fishermen who said that the largemouth they were pulling out of the lake weren’t as big as they used to be.
“Folks said it was noticeable, that it was a fairly recent occurrence,” said Vic DiCenzo, a biologist for the Virginia Department of Game and Inland Fisheries, who helped to conduct an agency study of the lake’s largemouth population.
DiCenzo said DGIF started looking into a possible outbreak of the virus in January after hearing accounts from fishermen that sounded much like descriptions of LMBV in the deep south.
“As they discussed their observances, I said, ‘you know, that sounds exactly like what happened in Texas and Florida and some of those fisheries,’” said DiCenzo.
DGIF sampled 570 largemouth during April and May from seven sites on the lake and received 170 more fish from largemouth bass tournaments to send off for testing. Results returned in late August from a U.S. Fish and Wildlife Services laboratory in Pennsylvania confirmed what game officials suspected: LMBV is widespread in the lake, and likely the reason largemouth are not maturing to full size.
Jackson Hudson, a member of The Concerned Bass Anglers of Virginia (CBAV) and a South Hill native now living in Richmond, helped to organize a January 2010 meeting with DGIF officials in Clarksville to discuss fishermen’s concerns. At that meeting, Hudson said, “We talked about it and everybody was saying the same thing: something’s different, something’s happened to Buggs Island Lake.”
It used to be “you could go to Buggs Island and catch 3 or 4 pounders every time you went and occasionally catch a 7 pounder,” said Hudson. “Now you rarely see anything more than 2 to 3 pounds.”
LMBV is not generally associated with fish kills, and it can exist in fish without triggering outbreaks of disease. Most diseased fish will appear completely normal, but once infected largemouth tend to swim too close the surface and have trouble staying upright. Scientists believe LMBV interferes with the swim bladder that controls the fish’s sense of balance.
By making it difficult for fish to swim, LMBV causes exhaustion and susceptibility to other problems, such as sores or weight loss. It seems to have its greatest impact on fish weighing two pounds or more.
“What you see is fish being weakened by the virus, and [then] something else gets it,” said DiCenzo.
DGIF officials have determined that the survival rates for largemouth bass ages 2-10 in Buggs Island declined from 64 percent in 2004 to 53 percent in 2010, a level well below average. By comparison, in 2008 the survival rate for Lake Chesdin near Richmond was 81 percent, and for Lake Gaston it was 66 percent.
“Fish die all the time, you just don’t always see it,” said DiCenzo. But “going from 64 percent to 53 percent can have a profound impact on the population …. That gets your attention, 53 percent.”
DiCenzo said past experience at other fisheries suggests it takes about two to three years for largemouth populations to rebound from outbreaks from LMBV. Fish with the disease are safe to eat, although often diminished in size.
“There’s nothing you can do, nothing can treat it,” DiCenzo said. ‘You have to let nature take its course.”
Even after largemouth populations develop resistance to the disease, added Hudson, several more years may be required for immune younger fish to grow into full-size adults.
“It’ll take 5-8 years for Buggs Island Lake to come back to where it once was,” he predicted.
BASSMasters, the top bass fishing league in the U.S., in a report on LMBV notes that “anglers have reported catching fewer bass, especially bigger fish” after outbreaks. “But indications are that an infected fishery will recover within a year or two,” BASS reports.
“More largemouth bass are killed annually by other known diseases or poor environmental conditions than by LMBV,” the circuit states. The BASS report continues: “Scientists do not know enough yet about the virus to determine if it will have long-lasting effects on bass populations. Indications are, however, that it will not harm fisheries long-term. Surveys on lakes following a kill suggest that fish populations remain within the normal range of sampling variability.”
While the causes of LMBV are not known, scientists agree that stressed-out bass are most prone to the disease. Unusually warm water may also play a role in outbreaks; DiCenzo speculated that hot summer weather could have contributed to the prevalence of the disease this summer.
“This summer was really, really hot and dry. Post-spawn, the fish were swimming in 90 degree water in June, and that’s not something the fish normally do because it was so hot,” he said.
When an outbreak of LMBV occurs, “it will make an impact fairly quickly,” added DiCenzo, pointing to the surge of complaints this year that fish size has dropped dramatically on Buggs Island. Looking back at the 2008 season, “anglers said the fishing was as good as it ever was,” he said.
While there’s little anyone can do to speed the natural recovery process for the largemouth population, officials say anglers can take measures to protect fish that are currently at risk of the disease. Tired and worn-out fish should be handled carefully, and not played out during the catch. Anglers also should take precautions to keep from spreading the disease to other bodies of water.
Hudson said the CBAV is raising money to produce educational materials on the virus and what fisherman can do to check its spread. The group hopes to put together a DVD and brochure to pass out at points around the lake, and at bass shows such as a popular event each year at the Virginia State Fairgrounds.
Officials also are urging bass tournament directors to avoid events during the hot summer months, in order to minimize the handling of fish at their most vulnerable periods. They are also urging fishermen to practice proper catch-and-release techniques.
“We want to educate people about the virus, what they can do reduce stress and the mortality rate, and also not spread virus to other waters,” said Hudson.
For example, he said, anglers should take care to disinfect the live wells in their boats after each fishing trip before going back out on the water. LMBV can live for days in a boat’s live well, but disinfecting the container area is easy to do and can prevent problems elsewhere, said Hudson.
In sampling area waterways this season, DGIF also found outbreaks of LMBV at two much smaller area lakes, Briery Creek Lake and Sandy River Reservoir, both in Prince Edward County. Hudson said DGIF has not sampled fish on Lake Gaston, downstream from Buggs Island, but he said he believes LMBV is likely to spread both downstream to Gaston and upstream on the Staunton and Dan Rivers.
“We all assume that if it’s in the lake, it’s in the rivers as well,” he said.
Bass fishing — for largemouth and striped bass — is a $6 million industry among communities on Buggs Island Lake, Hudson said, citing estimates for tourist spending and the number of fishermen at Buggs Island Lake. The good news is that the disease does not seem to affect stripers, crappie, catfish and the other fish types that attract outdoors enthusiasts to the area.
“I would certainly think people would still be coming to Buggs Island Lake,” said Hudson. “It’s a beautiful body of water.”