Is a killer stalking our lakes?
Scientists fear a deadly, Ebola-like virus is killing fish of all types in the Great Lakes.
By Norman De Bono
London Free Press
Posted May 3, 2007
They're two fishers on opposite sides of a debate over a killer virus in the Great Lakes.
The two lakes they fish account for the lion's share of all the fish caught in Ontario.
One, a commercial fisher who plies Lake Erie, says the catches are the biggest he's seen in years -- and he dismisses talk of the virus killing off massive fish stocks.
The other, a charter fisher in Lake Huron, has seen the size and quantity of his catch dwindle -- and he worries.
Separating their outlook on the bounty from the water is a deadly, Ebola-like virus some scientists fear could spell disaster for the Great Lakes fishery, an international commercial and sport industry worth more than $4.5 billion US.
Last May, tens of thousands of dead fish washed up on beaches around the Great Lakes as a result of the virus, say scientists with Ontario's Natural Resources Ministry and the federal Department of Fisheries and Oceans.
Now, with temperatures right, some observers are bracing for a similar die-off.
In the U.S., scientists say the virus is efficiently killing fish of all types.
And with a lack of genetic resistance to the virus in fish, comparisons have been drawn to the devastation the Dutch elm disease caused to elm trees.
Called hemorrhagic septicemia virus, or VHS, the virus causes hemorrhaging in fish -- as the Ebola virus did to humans in Africa -- and organ failure.
Jose Cabral of Wheatley, an Erie commercial fisher, isn't biting on the doom-and-gloom scenarios being cast.
"It's total (baloney)," he said. "Right now, the catches are astronomical. I have never seen catches like this.
"The only depletion I have seen is in our quota," he said, referring to
the amount of fish allowed to be taken from Erie.
Cabral owns a fishing trawler, the Theresa Maria, and has been fishing 29 years.
He catches pickerel, perch, bass and whitefish -- among the fish believed hit by VHS.
"I don't know who is coming up with these stories about viruses," he added.
But Barry Nash begs to differ. He's operated a fishing charter service out of Kincardine and Port Bruce, along Huron. The salmon he covets are smaller and there are fewer of them.
"There is something going on. It is terrible now. I don't know what's happening," said Nash.
About five years ago, he said, he was catching 25, 20-pound fish a trip. But "today, I will get five, 10- to 12-pound fish in a day. There is a decline in the total and the size."
It's believed the VHS virus entered the lakes through the ballast water of ocean-going freighters, just as another scourge -- the zebra mussel -- entered the freshwater system more than 20 years ago.
Zebra mussels have diminished the population of little shrimp, called diporeia, in Lake Huron that are the favourite food of many fish, including salmon -- and that may also be to blame for the changes Nash is noticing.
But he's not surprised fishers in Lake Erie -- the most bountiful of the Great Lakes -- are boasting of no impact yet.
"It has always been a very fertile lake -- it doesn't surprise me it is not affected as much," but that doesn't mean there's not a problem, he said.
Just as thousands of fish washed ashore last May, scientists are bracing for the same thing this month, since the VHS virus is most active in cooler waters of 4 to 15 C.
The U.S. and Canada have tried to contain the virus by restricting transport of fish and live bait and by telling boaters to wash their craft when moving between lakes.
Commercial fishing is a year-round industry, but some lake areas are closed at different times of the year, said Peter Meisenheimer, executive director of the Ontario Commercial Fisheries' Association in Blenheim.
Erie is the world's largest freshwater fishery, he said. Eighty per cent of the value of all fish caught in Ontario comes from Erie, another 10 per cent from Huron and the rest from other lakes.
ABOUT THE VHS VIRUS
What: Viral hemorrhagic septicemia, known as VHS, causes hemorrhaging and organ failure in fish. Believed to be behind massive fish die-off in the Great Lakes, it's left officials on both sides of the Canada-U.S. border worried about the fallout for lucrative commercial and sport fishing.
Scale: While the tens of thousands of fish that have been reported washed ashore from die-off may seem like a large number, that's relatively small given the bounty of the lakes. In Lake Erie, for example, there are millions of yellow perch, said Pete Misenheimer, executive director of the Ontario Commercial Fisheries Association, About 15 million pounds of perch and pickerel were pulled from Erie last year.
Track record: The virus began appearing in fish in 2003 and the first big die-off was seen in May 2006. The virus is most active when the water is cold, so scientists expect dead fish to begin appearing soon.
- John Cooper of Ontario's Natural Resources Ministry: "It is very early to know what the impact of this will be, but we consider this a threat and we want to slow it down from spreading into new areas as much as we can."
- Brian Souter of the Department of Fisheries and Oceans: Said the good news is the virus cannot be transferred to humans. "This is a very real problem. Some species have been hit hard, but it is difficult to say whether the numbers are significant in terms of the whole fish population."
- Misenheimer, of the commercial fisheries' association: "We are worried about this, that it was able to get in the (freshwater lakes) system and we are now not able to stop it."