From the Star Tribune (Link to Story)
Mille Lacs has zebra mussels
Doug Smith, Star Tribune
August 13, 2005 ZEBRA0813
It’s troubling. It’s disappointing. And it was probably inevitable.
That’s how state officials described the discovery of zebra mussels in Lake Mille Lacs – one of Minnesota’s largest, most popular and most heavily fished lakes.
The Department of Natural Resources announced Friday that it had found two zebra mussels in separate locations during a routine underwater survey of the 132,000-acre lake about 75 miles north of the Twin Cities.
But it’s uncertain what impact the exotic species could have on Mille Lacs and its renowned walleye fishery.
“This is certainly not welcome news,” said Gary Montz of the DNR. But, he said, “I wouldn’t even begin to predict the impacts. It’s just too early. We’re not even certain there’s a reproducing population, although [the discovery] would seem to suggest that.”
Zebra mussels can foul beaches, clog water intakes, harm native mussels and interfere in lake food chains. In great numbers, they can change water clarity, which can affect plants and fish.
Officials plan to continue searching the lake to determine whether the zebra mussels are widespread. But a check of more than 20 sites by scuba divers turned up just the two adult zebra mussels.
Mille Lacs resort owner Terry McQuoid, told of the findings Friday, shrugged off the news.
“It’s not a big deal,” he said. “Other lakes have them. It’s maybe not ideal, but it was just a matter of time that they would come here. Hopefully, they might not hurt us.”
Montz said it likely would take some time before zebra mussels — if they are reproducing — would affect the lake. And the effects could range from minimal to severe.
“We definitely don’t think this is the end of the world,” he said. But he called the discovery “troubling.”
One thing is certain: It underscores the continuing spread of exotic species in state waters. And the heavy use of Mille Lacs increases the likelihood that boaters could inadvertently spread zebra mussels to other lakes via live wells, bait buckets, boats or trailers.
“It certainly points out the problem we’re facing with invasive species, whether it’s zebra mussels, Asian carp, round gobies, curly-leaf pondweed or Eurasian water milfoil,” said Ron Payer, DNR fisheries chief.
“So many people from all over the Upper Midwest fish Mille Lacs; it could be a source of zebra mussels going to other lakes.”
And there’s no getting rid of zebra mussels once they are in a lake or river.
“There’s not a lot you can do once they are in a system,” Payer said.
Officials speculate that the zebra mussels in Mille Lacs arrived on or in a boat that had picked up the mussels elsewhere. “They probably hitched a ride,” said Montz, the DNR’s coordinator for zebra mussel study.
In the larvae stage, the mussels are microscopic and can be accidently transported with water in live wells or bait buckets. The adult mussels can attach themselves to boats, trailers and aquatic vegetation.
Mille Lacs is the state’s third inland lake known to be have zebra mussels, natives of the Caspian Sea near Russia that spread to the Great Lakes in the ballasts of oceangoing ships. They have been found in Lake Superior, the Mississippi River, Lake Zumbro near Rochester and Lake Ossawinnamakee near Brainerd.
The best-case scenario is that the zebra mussels don’t yet have a good foothold in Mille Lacs and that if they do reproduce there they may not thrive in large numbers. The worst-case scenario? Montz refers to Lake St. Claire, between lakes Huron and Erie, where zebra mussels were first detected in 1988. They reproduced in huge numbers.
The lake, once a prime walleye fishery, changed dramatically.
“Zebra mussels filter water; they cleared up the lake enough that aquatic vegetation got established in a lot of areas,” Montz said. “That provided cover for bass and northern, and those populations grew. The fishery changed from an abundant walleye fishery to a bass and northern fishery.”
What about Mille Lacs?
“I wouldn’t speculate that Mille Lacs would lend itself readily to a major change, but we just don’t know,” Payer said.
Meanwhile, officials emphasized that boaters on Mille Lacs and other state waters can help prevent or slow the spread of exotic species. They recommend the following:
• Remove all aquatic plants from boats, trailers and equipment.
• Drain all lake water, including live wells, bilges and bait buckets, before leaving an access site.
• Wash boats with hot water or let boats dry thoroughly for five days before launching them in other waters.
