minnesota zebra mussels – Zebra Mussels

Zebra mussel madness in Alexandria area

Dr. Daniel Molloy described three major impacts caused by the spread of zebra mussels.

By: Wendy Wilson, Alexandria Echo Press

Dr. Daniel Molloy described three major impacts caused by the spread of zebra mussels.

One is recreational. Beach-goers could cut their feet on the sharp mussel shells.

Live mussels also wash onto shore, leaving behind an offensive odor.

The industrial impact of zebra mussels is also significant.

The creatures attach to and clog pipes, causing a myriad of problems and financial burden.

According to Dick Osgood, certified lake manager, irrigation systems for lawn watering are also becoming inundated with mussels.

The third impact of the mussels is ecological.

“[Zebra mussels] feed voraciously by filtering on algae and the next domino to get hit is the microscopic animals that are in that water,” he said. “The dominoes start to fall.”

He explained that insects and fish normally would eat the microorganisms.

“The food chain gets an impact and also the water starts to become clearer because they’re eating those microscopic plants that are making it kind of pea-soupy. Sunlight now can go further down, striking the bottom so that aquatic weeds can start to grow where they weren’t growing,” he said.

The zebra mussels also accumulate polychlorinated biphenyls (PCBs) “which are nasty poisons – you already have that in these lakes,” Osgood said. He also noted, “With zebra mussels… they filter out the algae but they don’t filter out the toxin strains of algae.”

Some of these toxins have been linked to human health impacts, especially in water supply reservoirs.

“They are beginning to find Alzheimer clusters in communities that get their drinking water from reservoirs that have blue-green algae blooms that have formed toxins,” Osgood said.

Zebra mussels talk draws full house

By Casey Merkwan
Reporter

Concerned community members and experts packed a room at the Chanhassen Community Center last week to learn more about the dreaded zebra mussels.

More than 50 people attended a forum that featured speakers Steve McComas, an aquatic biologist and ecologist, Luke Skinner from the Minnesota Department of Natural Resources and Eric Evenson, district administrator of the Minnehaha Creek Watershed District to talk about the problem of zebra mussels and what’s next for Minnesota lakes.

Skinner said there is no safe way to eradicate zebra mussels, so the focus is on preventing any further spreading.

“There’s a lot of concern about a lot of invasive species but right now the zebra mussel is the poster child for spreading in the state,” Skinner said.

Skinner said it is possible to kill off zebra mussels but there’s risk of killing other species. He also said the larger the lake the harder they are to control.

“In a lake like this [Minnetonka] with this many bays and islands and stuff, the reality of trying to manage it here is it’s not going to happen,” he said.

Since the discovery of zebra mussels in July of last year, experts say the key is to prevent them from spreading.

It’s possible the non-native invasive species have been in Lake Minnetonka for more than two years.

“They were also found on the other side of the dam of Lake Minnetonka so theoretically Minnehaha Creek is considered to be infested as well,” McComas said.

Zebra mussels originated from the Black and Caspian seas in Europe. It is suspected that the species traveled to the United States via cargo ships in the late 1980s.

After the discovery of the zebra mussels in July, agencies performed an enhanced assessment to determine the distribution of the infestation and to find adult zebra mussels to lead them to a breeding point.

“They were fairly hard to find,” McComas said. “In a big lake it really is looking for a needle in a haystack trying to find a breeding population.”

Divers didn’t find a breeding spot. McComas said there was 100 hours of dive time, 30-40 volunteers and 20-30 spots where zebra mussels were found in Lake Minnetonka, mostly on the east side of the lake.

Lake Minnetonka and neighboring lakes were also assessed for how hospitable the lakes were for zebra mussel population growth.

McComas said the calcium levels in all 26 bays of Lake Minnetonka were high enough that they could support optimal growth of zebra mussels.

Other factors that are optimal for zebra mussel growth are PH levels, the right concentration of chlorophyll and bottom conditions.

Zebra mussels attach easily to hard surfaces with substrate, for example rocks. If the bottom of the lake is sand and silt, the mussels can attach to each other as well.

Lake Minnetonka has the conditions that would support moderate growth of zebra mussels and 43 percent of lake bottom could be colonized, McComas said.

Christmas Lake has the potential to have 60 percent of the lake bottom colonized, according to McComas.

Zebra mussels kill native mussels and also compete with young fish for food. They can also block underwater pipes.

McComas said zebra mussels start spawning when the water temperature reaches 54 degrees.

Currently, water temperatures are in the high 30s. By late May the water temperatures will raise to optimal spawning time.

“This isn’t something that the state can do on their own, this isn’t something the watershed district can do on their own, this isn’t something that counties can do on their own. This is going to have a coordinated effort, a cooperative effort to really get anything to happen here and it is going to involve all the agencies, it’s also going to have to involve lake associations and individuals out there,” Evenson said.

As a result Evenson, Skinner and McComas emphasized the need to prevent further infestation of the zebra mussels.

Evenson suggested implementing a red lake, blue lake program to help stop spreading.

The program would use a red sticker to identify when a boat has been in waters infested with zebra mussels. A boat could not enter a lake without zebra mussels until inspected.

The legislature has also gotten involved: a new drain plug law took effect on July 1, 2010. The law states that a person leaving waters of the state must drain boat equipment by removing the drain plugs, bailers, valves or other devices that hold water.

On March 16, Gov. Mark Dayton announced his support for legislation that hopes to minimize the spread of aquatic invasive species.

The bill would require more thorough inspections, double penalties for violations, allow local law enforcement to retain civil penalty amounts for citations issued by their agency, require training for lake providers and require watercraft and operators to have a decal that lists invasive species rules, like a sticker.

The experts encouraged community members to vocalize their concerns with their elected representatives and to also educate their neighbors to slow the infestation of zebra mussels.

Ramp gates a solution for zebra mussels?

Article by: LAURIE BLAKE , Star Tribune

Homeowners on Christmas Lake are pushing for a better way to protect their clean waters.

In another grass-roots attempt to stop the spread of zebra mussels from Lake Minnetonka, homeowners on nearby Christmas Lake are angling to have a code-activated gate installed on the lake’s solitary boat ramp.

“There are huge numbers of lake homeowners who don’t feel the Department of Natural Resources is doing enough,” said Joe Shneider, president of the 140-member Christmas Lake Homeowners Association.

“We can’t just do what we have done in the past, which is monitor and communicate and educate, because it’s just not enough.”

Christmas Lake is one of the cleanest, clearest lakes in the metro area because it is deep, spring-fed and gets no farm runoff.

The lake’s boat ramp on Hwy. 7 in Shorewood is a stone’s throw from Lake Minnetonka, where zebra mussels were discovered last summer. Many boaters take a ride or fish on Lake Minnetonka and then, without having to be inspected for unwanted aquatic plants and animals, go on to Christmas Lake, Shneider said.

Christmas Lake homeowners would like the Minnehaha Creek Watershed District to test the ramp gate idea.

“We would really like to see a strong statewide program put in place to control the spread of invasive species, but if the state doesn’t do that we are willing to step up and do something,” said watershed district administrator Eric Evenson.

The idea is to require boaters to go to one of several locations for an invasive species inspection, where they could get a punch code, similar to an automatic car wash, to raise the gate to the boat ramp, Evenson said.

“If we don’t do something, we are going to lose what people want to get to the lake for in the first place,” Evenson said.

Lake access part of culture

The request comes just weeks after homeowners around Fish Lake in Maple Grove sought to close its only access ramp when it wasn’t staffed for inspections.

The DNR, which would have to approve the gate experiment, has so far refused to limit lake access in the name of controlling invasive species.

“We are concerned about preventing the spread of invasive species but we need to find ways to do it that still allow people to recreate on the lakes,” said Steve Hirsch, director of the division of ecological and water resources.

“Access to lakes is kind of part of the fabric of Minnesota’s culture so I don’t think the DNR can be the sole entity that decides we are going to start trading off access to lakes,” Hirsch said.

The agency is discussing the matter with the state attorney general’s office. Hirsch declined to describe the discussions.

The DNR’s approach to aquatic invasive species has been to station inspectors at busy lakes during peak hours and educate the public about how invasive plants and animals are spread. The agency is recommending that legislators provide more funding for expanded lake inspections and enforcement.

Hirsch acknowledged that even if legislation providing more inspectors passes, lakes would not have complete inspection coverage.

Gate approach worth a shot?

At Fish Lake Regional Park, operated by Three Rivers Park District, the homeowners’ request to gate the ramp when inspectors are not present was turned down because it was inconsistent with park and DNR policies. Three Rivers officials said they welcomed more volunteer inspectors.

A gated approach at the Christmas Lake boat ramp is worth trying, said Steve McComas, owner of Blue Water Science in St. Paul who specializes in lake and watershed management. The boat ramp owned by Shorewood is the only publicly owned piece of property on Christmas Lake.

“I wouldn’t say I would like to see this on every single lake, but it certainly is a noble experiment. Why not try it and see what kind of problems we incur and see if it works?” McComas said.

Said Shneider: “We seem like a wonderful pilot because we do only have one boat ramp and the water quality is so good. If you are going to protect things, gosh, protect the best.”

Christmas Lake homeowners use the ramp to put their own boats in the water, Shneider said.

Shorewood, which operates the ramp under an agreement with the DNR, supported the watershed district’s application for a grant to pay on-site inspectors for the ramp, but the City Council has not addressed the gate idea, said city administrator Brian Heck.

“One of my questions is: Do we know for certain that there aren’t zebra mussels there already,” Heck said.

The watershed district is taking samples in the lake to find out.

Zebra mussels in Lake Minnetonka

TOM MEERSMAN, Star Tribune

Zebra mussels have invaded Lake Minnetonka, a breach of the state’s defenses against invasive species that threatens to dramatically change the character of Minnesota’s 10th-largest lake within just a few years.

Department of Natural Resources biologists confirmed Wednesday that a small number of mussels are attached to rocks along the shore, and their size suggests that a reproducing population has been in the lake for at least a year.

In places where they’ve become established, the fingernail-sized mussels proliferate by the millions, consume food needed by fish, clog water intake pipes, ruin fish spawning beds and litter beaches and shallow areas with razor-sharp shells.

The mussels were found on the east side of Wayzata Bay near Hwy. 101. That’s not far from the lake’s outlet to Minnehaha Creek, raising fears that the mussels may spread into that waterway, or may have done so already. Minnehaha Creek is connected to lakes Nokomis and Hiawatha in Minneapolis.

For years DNR officials have worked with the Lake Minnetonka Conservation District and others to educate boaters and anglers to prevent the spread of zebra mussels. They also inspected boats and trailers and directed owners to remove plants, mussels and water from bait buckets and vessels that traveled in infested lakes and rivers. The efforts may have bought some time, but they didn’t stop the mussels’ entry into Minnetonka.

“Unfortunately, zebra mussels still found their way to the lake,” said Luke Skinner, supervisor of DNR’s invasive species program.

The discovery was dreaded news for Dick Osgood, president of the Lake Minnetonka Association, which represents about 600 lakeshore owners and businesses.

“This has been our fear all along, and keeping them out has been our top priority for the last ten years,” said Osgood.
Lake Minnetonka is the most heavily used lake in the state, he said, with an estimated 200,000 boats plying its channels, bays and open water annually.

With that amount of exposure, the discovery of mussels was not unexpected, said Osgood, but it was still a major disappointment.

“Bottom line is, I think they’re here to stay,” he said. “Not that we won’t do everything possible in rapid response, but I think it’ll change the lake forever.”

Osgood and representatives of the Minnehaha Creek Watershed District plan to do a quick assessment of the lake to see if they can find mussels in other places. There’s a chance, he said, that if they are only in one area, the mussels could be removed or killed before they spread further.

DNR officials said that the number of zebra mussels found was very low and that they would investigate the situation this week and beyond, including an extensive survey of the lake later this summer.

Osgood advocates limiting boat traffic in the infested waters, at least until the extent of the invasion is better understood.
In other places, he said, the discovery of zebra mussels is usually followed by 1 to 3 years of “lag time” in which a few more infested areas are found. At some point, usually about five years after the initial discovery, he said, the populations explode and the lakes start to change, sometimes unpredictably.

In some areas the numbers of different fish species increase or decrease, seeking a new balance as habitat and food sources change. Native mussels usually die out. And because zebra mussels constantly filter sediment and nutrients, water often becomes noticeably clearer.

That may please some, said Osgood, but it also means that light will penetrate deeper, boosting the growth of plants such as Eurasian water milfoil, an invasive that’s already a major nuisance and expense to control in Lake Minnetonka.

Resident spotted mussels

A local resident found the mussels in the lake early this week and reported them to the DNR. Skinner said that anyone else who finds mussels should contact the agency.

Zebra mussels are native to Eastern Europe and western Russia, and likely came to the Great Lakes in ballast water of ocean-going ships that traveled up the St. Lawrence Seaway. They were discovered near Detroit in 1988. Their first appearance in Minnesota was in 1989 in Duluth harbor, and they subsequently spread to 17 inland lakes, including Mille Lacs, Prior, and Le Homme Dieu and to portions of the Mississippi, St. Croix and Zumbro rivers.

Udai Singh, senior hydrologist and water quality specialist for the Minnehaha Creek Watershed District, said plans for what to do next are still very preliminary. If the mussels are firmly in the lake, he said, the district may install equipment at various locations downstream in Minnehaha Creek to check for them. The discovery in Minnetonka is “really unfortunate,” Singh said, and has already jump-started a new array of activities.

“Now since prevention is out the window, we will be more working in terms of control and management of them,” he said.
Tom Meersman •StarTribune