New fish virus could be a little as 2 years away from Lake Michigan
By Joe Boomgaard
Ludington Daily News
Published January 9, 2007
"Don’t shoot the messenger.”
That was Gary Whelan’s message about a new, potentially devastating fish disease as he began his talk to the more than 100 anglers and concerned citizens Saturday at the Sea Grant Fisheries Workshop at the Ramada Inn of Ludington.
Whelan, the state’s manager of fisheries hatcheries talked about the affects of Viral Hemorrhagic Septicemia and the frustrations of dealing with the federal government regarding the virus.
VHS causes massive internal hemorrhaging of the internal organs of a known 37 species of fish in the Great Lakes basin, including muskellunge, freshwater drum, yellow perch, bluegills, crappie, shad, northern pike and suckers. It is not known to cause harm in humans. Emerald shiners, a popular baitfish, are also known to be infected.
The presence of VHS “has not been confirmed in salmonids, and it’s not known if they’re susceptible to this isolate” or strain of the virus, Whelan said.
An industry alert published by the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) said the strain infecting fish in the Great Lakes “appears to be a new strain of the virus” and noted the virus was known to affect salmonids. The virus is also known to occur in several different isolates — each with their own genetic type, according to a DNR briefing paper.
Whelan traced the movement of VHS since it was initially noticed in muskellunge in Lake St. Clair in the fall of 2005. Since then, it has been noticed in fish in Lakes Erie and Ontario. VHS likely got to the Great Lakes in 2002 via ballast water in ocean-going ships from the Maritime Provinces, according to Whelan.
“There are not a lot of other vectors besides ballast water that made sense to us,” he said.
He said if the virus can spread by infected fish, it could be seen in Lake Huron and Lake Michigan in two to four years because of the “tremendous amount of interchange between the lakes.”
“But if ballast water is the vector, all bets are off,” Whelan said, noting that tests in the major shipping ports of Duluth and Chicago have thus far come up negative.
“If it gets to Chicago, it’ll get into the Mississippi River system and then it becomes a national problem,” he said.
“It will have an effect on native fish populations. How much will it be, we really don’t know. It’s a new virus and we don’t have a lot of experience on it. The experts can’t even give us good answers on it. For fish populations that have never seen VHS — we don’t know what it will do. We’re hoping to get research done this year on susceptibility.”
The virus does well in cold temperatures, surviving in water as cold as 35 degrees and living optimally in water cooler than 58 degrees.
The APHIS ban and the virus itself could cause havoc for the bait industry and, tangentially, sport fishing, he said.
In October, APHIS issued a shipping ban on all live fish from the Great Lakes region, a move Whelan said he was made aware of the day before the ban was announced via a “listen-only” conference call.
A meeting was held Oct. 31 and Nov. 1 in Washington, D.C. to work out some of the problems caused by the shipping ban after many fisheries managers were taken by surprise.
“It has not been a terribly comprehensive public process,” Whelan said of APHIS’s procedures. “It’s not how we would do it.”
The initial order would have prevented the movement of live fish to research laboratories and slaughter facilities, but under the amended order issued by APHIS Nov. 14, such movement is allowed.
A public hearing sponsored by APHIS about VHS is scheduled for 8:30 a.m. to 12 p.m. Wednesday, Jan. 10 at the Crowne Plaza at the Detroit Metro Airport in Romulus.
The order applies only to live fish, and Whelan said if APHIS stays consistent with its past orders, he didn’t suspect fishermen who travel to Ontario and other parts of Canada to have problems bringing fish home. The most often affected parts of the infected fish are the internal organs, which are not near the skin or the flesh, according to Whelan. Freezing fillets reduces the viability of VHS, he said, and fresh fillets pose only a “low risk.”
The state’s Skamania strain steelhead program, which originates from Indiana hatcheries, should not be at risk since all of the smolts are tested to ensure they are disease-free before shipment, Whelan said. The state stocks the Skamania strain in the Manistee River. It gets the smolts for the program by trading Little Manistee strain steelhead smolts with Indiana’s Department of Natural Resources.
Other local stocking programs may be affected. DNR Lake Michigan Management Unit Fisheries Supervisor Tom Rozich said VHS could affect local walleye and muskellunge plants.
“The walleye rearing program for ’07 is up in the air right now,” Rozich said. The DNR has collected samples from the Titabawassee River and will collect samples in the coming months from the Muskegon River and Bay de Noc, he said.
The presence of the virus in baitfish could affect the state’s muskellunge rearing at the Wolf Lake Hatchery, as well, according to Rozich.
“I’m sure the muskie feed will have to be tested and certified disease-free,” Rozich said.
VHS is frequently carried in sexual fluids, including ovaries or spawn, often used by anglers as bait. Whelan said the state hasn’t yet taken a position on the movement of eggs.
“I caution against moving eggs around all over the place, but it depends on the source of what the eggs is,” Whelan said. “If they come out of a completely clean waterbody, it wouldn’t be a problem at all. If they’re take eggs out of Lake Erie right now and coming into Michigan, I’d be pretty concerned about that because they have a high probability of hauling it back with them.
“If the eggs are fresh and still have the ovarian fluids with them and come out of positive water — and those fish happen to be also positive — they’re going to bring that disease with them. It can last up to two weeks in ovarian fluid if it’s kept cool. There’s not a lot of data on how long this virus lives outside of a fish.”
While the government agencies keep close watch over the spread of the virus and try to slow its movement, Whelan said it’s up to anglers and boaters to help. As with preventing the proliferation of other exotic species, fishermen should not transport bait from one waterway to another and should avoid moving livewell and bilge water. Disinfection of gear is also important, he said.
“(VHS) is kind of a weenie,” Whelan said. “You can damn near look at it and kill it.”
Leaving gear exposed to sunlight for a while or cleaning with a bleach solution should do the trick, he said.
Whelan asked anglers to report finding fish showing symptoms of the disease to the DNR as soon as possible. VHS is most noticeable on fish organs and causes them to look bloody. Whelan said it’s best to keep the fish on ice and not freeze it.
On Monday, the Ontario Ministry of Natural Resources placed a ban on the harvesting of live bait from the “infected zone” — from the St. Clair River through the rest of the Great Lakes waterway to the south and east, including Lakes Erie and Ontario — and on transporting live bait out of the “buffer zone” — which includes Ontario’s Lake Huron shoreline and an area north of the infected zone. Live fish movements in the “virus-free zone” in northern Ontario are not restricted.