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Jim Winton, chief of fish health for the U.S. Geological Survey in Seattle, said the strain of viral hemorrhagic septicemia that has been discovered in Wisconsin is dangerous because the state’s fish species have no immunity. That makes it especially important, Winton added, that the state do everything it can to prevent spread of the virus, which has been confirmed in fish in the Lake Winnebago chain and in Lake Michigan.
But Winton said this is more than likely just the beginning.
“I wouldn’t bet against it already being in the Mississippi River system and spreading,” Winton said. “The horse is out of the barn but we just don’t know how far.”
Heeding the ominous message of Winton’s science, the state Department of Natural Resources has taken numerous steps to better control the movement of water and bait by anglers and boaters, has halted stocking of fish from its hatcheries, and has established a permit system for bait dealers.
The state Department of Agriculture, Trade and Consumer Protection has issued fish health advisories on the disease to fish farms, which the agency regulates, but has not toughened any of its permitting regulations for commercial bait dealers.
While the virus is deadly to fish, it cannot be contracted by humans. The disease is spread through the water in which infected fish have shed urine or reproductive fluids. Fish that get infected die from internal bleeding.
Although it does not affect human health, the potential of the virus to kill as many as 25 different species of fish and to kill large numbers of fish has prompted DNR officials to label the presence of the disease a crisis for the state’s $2.3 billion a year fishing industry. The state is the second most visited fishing destination in the country, according to the DNR.
Though some regulations on the movement of live bait have been toughened, DNR officials remain concerned that some regulatory gaps exist, especially when it comes to the movement of untested and potentially infected bait minnows from other states into Wisconsin.
“What regulations are there in other states?” asked Mike Staggs, fish director for the DNR. “What I’m not satisfied with is quality control of the bait that is being made available to Wisconsin anglers.”
Some fear the DNR has not gone far enough in its own efforts. The Wisconsin Wildlife Federation, for example, was critical of the Natural Resources Board for not putting in place a statewide ban on the movement of bilge water and live bait. Instead, the board, which sets policy for the DNR, approved emergency rules that establish a ban for the Lake Winnebago chain, where the virus was first found. The board had already approved a ban that applies to Lakes Superior and Michigan as well as the Mississippi River. But on all other state waters, restrictions remain voluntary.
Staggs said that while a statewide ban was not proposed, fisheries officials were satisfied with a more limited ban because the emergency rules include provisions for a statewide ban to become automatic if the virus surfaces in any other Wisconsin waters.
The board also approved a wild bait harvest permit system. Under the system, people who harvest and sell minnows from the wild will have to carry a free bait harvest permit and keep records of their bait collection and sale. The agency mailed permit application forms last week to 650 licensed bait dealers across Wisconsin, including an estimated 250 who harvest bait from the wild and sell it.
In addition, the agency is doing some testing for the disease, mostly in dead fish. A more ambitious testing program will get under way later this summer when waters warm and the virus is more evident, Staggs said. He added that additional laboratory facilities are needed before more extensive testing is undertaken.
While the DNR is responsible for regulating the harvest and sale of bait from the wild, DATCP regulates fish farms, including the sale of farm-raised minnows for bait. Donna Gilson, a spokeswoman for the agency, said dealers bringing bait farm-raised minnows into the state must provide a veterinary health certificate that includes negative VHS test results within the past year. Currently, however, there is not a VHS testing requirement for commercial dealers moving fish or eggs within Wisconsin.
“Regulations evolve as the situation evolves,” Gilson said. “If this starts popping up all over the state, if that happens, then we may revisit the bait issue.”
Gilson said the agency is working with the Wisconsin State Patrol to better monitor movement of fish into the state. On Monday, she said, State Patrol officers stopped two trucks from Minnesota that were attempting to bring bait minnows into Wisconsin without testing information.
Winton, the USGS scientist who has extensively studied the virus, said such diligence is necessary because of the importance of preventing spread of the disease. Scientists, he said, are aware of several different strains of the virus, which is among the oldest known fish viruses.
But the strain that has shown up in the Great Lakes is new and fish here have had no exposure to the virus, meaning their immune systems have no defense and are “highly susceptible.”
Winton compared the potential spread of the virus to the spread of a human disease, such as smallpox or the 1918 flu virus, through a population with no immunity.
“This is extremely troubling,” Winton said.
Special species
Wisconsin fish experts are paying particularly close attention to the potential impact of the virus on species that are especially
important to the state’s anglers.
Muskellunge: Though no muskellunge from the state have been found to have the virus, the disease has caused high mortality among Great Lakes muskellunge in New York.
Trout: A dead brown trout from Lake Michigan tested positive for the virus last week and trout have been killed by the virus in several other locations throughout the Great Lakes states.
Sturgeon: So far, the disease has not been found in sturgeon, important because the Lake Winnebago chain, where the virus was first discovered in Wisconsin, is home to one of the state’s largest and healthiest populations of sturgeon.
Precautions
The state Department of Natural Resources is asking the public to take the following precautions to avoid spreading VHS:
Ron Seely is a reporter for the Wisconsin State Journal in Madison.
