Ironwood Daily Globe:
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Lakes face new threat
Published Thursday, March 22, 2007 3:49:28 PM Central Time
By RALPH ANSAMI
Globe News Editor
Another month, another invader.
Add VHS to the list of threats to the Great Lakes.
Viral hemorrhagic septicemia is a fish disease that's as horrific as its scientific name implies.
While the disease has been found in Lake Huron, it luckily has not yet reached Lake Superior, Department of Natural Resources fisheries biologist Steve Schram, from Bayfield, Wis., told the Saxon Harbor Boating Club recently.
Usually found in water between 37 and 54 degrees, VHS can affect freshwater fish and marine species, but it is not a human health concern.
It affects fish by attacking their internal organs, muscles and skin. Fish suffering from VHS have bulging eyes and their internal organs swell. Those symptoms can also be from other diseases, however, Schram said.
Schram said the DNR is taking several steps to keep the disease out of Lake Superior, including not bringing in wild fish that might be infected to inland hatcheries.
"We don't have a hard and fast policy yet," he said.
Fishermen attending the recent meeting feared VHS may one day be spread to Lake Superior through ballast water on ships. Fishermen complained that's often how exotic species enter the Great Lakes.
Schram said the disease could lead to moratoriums on the stocking of some species of fish, although he added, "There are more unknowns than knowns at the time."
Once a fish is infected with VHS, there's no known cure. Not all infected fish develop the disease, but they can carry and spread it to other fish. VHS has been blamed for fish kills in Lake Huron, Lake St. Clair, Michigan; Lake Erie, Lake Ontario, the St. Lawrence River and Conesus Lake in western N.Y.
VHS was first discovered in the mid-20th century in Europe, where it was originally a significant and costly disease of cultured rainbow trout. Since its initial discovery in Europe, four strains of the VHS virus have been identified, including both freshwater and marine strains.
Species involved in fish kills linked to VHS included muskellunge, smallmouth bass, northern pike, lake whitefish, gizzard shad, yellow perch, black crappie, bluegill, rock bass, white bass, redhorse sucker, round goby, burbot and walleye. Chinook salmon, bluntnose minnows and emerald shiners have also tested positive for VHS.
Samples from fish kills in the Thunder Bay area were collected last fall, including lake whitefish and walleyes.
Kelley Smith, chief of the Michigan DNR Fisheries Division, said VHS was implicated as the probable cause of death of those fish.
A number of chinook salmon observed at Michigan's Swan River egg-take station last fall also showed signs of VHS infection, according to the DNR. The DNR has since taken steps to disinfect the eggs from the hatchery and they've been successful, according to the DNR.
Michigan's waters of Lake Huron, including Saginaw Bay and other areas, have been classified as a VHS Positive Management Area
Michigan anglers are asked not to move live fish between the Great Lakes and inland waters, particularly minnow species, and to use standard disinfection techniques for boats, live wells and other equipment.
Citizens are encouraged to report sick fish or fish kills to the local DNR office or on the DNR Web site at www.michigan.gov/dnr.
It's no idle threat.
"VHS is one of the biggest challenges to face the Michigan aquaculture industry in its history," said Michigan Aquaculture Association president Chris Weeks. The MAA focused on VHS at its 20th annual conference Feb. 6-7 in Cadillac.
In Wisconsin, as Schram and Mike Seider, another WDNR fish biologist, were discussing the possible discontinuance of the chinook planting program in Lake Superior, Schram said, "We'll have to make some decisions. VHS could make it for us."
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Shipping ban proposed
With new invasive species being discovered in the Great Lakes on the average of every six months, some conservationists are proposing a ban on ships until they can stop discharging contaminated ballast water.
"This is being done out of frustration," said Jennifer Nalbone of Great Lakes United. "This is a decision we've made because the federal government has failed to protect the Great Lakes."
Great Lakes United and the Canadian Autoworkers Local 1520 are calling for a moratorium on ocean-going vessels access to the Great Lakes until the Canadian and U.S. governments put in place regulatory solutions to curb the influx of exotic invaders.
During the moratorium, international cargo bound for the Great Lakes region could be offloaded before reaching the Lakes and moved via transportation options such as barges, rail or trucks, Great Lakes United proposes.
The St. Lawrence Seaway officially opened its 2007 shipping season Wednesday.
Since Seaway officials opened the Great Lakes to deep draft shipping and ocean-vessel access in 1959, a total of 65 percent of the aquatic invasive species entering the Lakes were brought in by ocean vessels, GLU claims. They include invaders such as the spiny water flea, round goby, zebra mussel and quagga mussel.
Efforts to halt zebra and quagga mussels alone are estimated to cost $500 million each year over the next five years, GLU claims.
Meanwhile, U.S. legislation dealing with ballast water has been stalled in Congress.
Michigan plans to require overseas freighters to not discharge ballast water or to take steps insuring it isn't contaminated.
Other Great Lakes states, including Wisconsin, are considering similar rules, according to a Tuesday story in the Milwaukee Journal-Sentinel.
For more information about the GLU petition drive, visit the Great Lakes United Website.
--Ralph Ansami
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