Tag: Zebra Mussels

Zebra mussels are impacting Lake Minnetonka’s water quality

April 26th, 2016

MCWD releases findings of five-year study

Zebra mussels have caused significant changes in Lake Minnetonka’s water quality, according to findings of a study by Minnehaha Creek Watershed District (MCWD). The District has been monitoring the lake’s zebra mussel population since they were first detected there in 2010. Five years into the study, which was developed in partnership with Blue Water Science, MCWD released its findings on Thursdsay, April 21 at its AIS Spotlight, a gathering of community leaders at Minnetonka Community Center.

The District has discovered the biggest water quality changes are occurring among bays with the highest number of zebra mussels. In Wayzata Bay, which the population topped out at an estimated 200,000 zebra mussels per square meter in 2014, there has been an increase in water clarity and a decrease in algae (Chlorophyll) and Phosphorus. Those changes are not as prevalent in bays with lower zebra mussel populations. In Halsted Bay, which has 28 zebra mussels per square meter, there has been little change in water clarity, Chlorophyll and Phosphorus.

MCWD has also learned what conditions zebra mussels need to thrive. The highest populations are in bays with moderate levels of algae, an important food source for zebra mussels, and the lower populations are in bays that either have very high or very low levels of algae. Lakes with very high algae levels tend to be dominated by blue-green algae, a poor food source for the mussels, and lakes with very low algae content simply don’t have enough food available.

“This detailed data on how zebra mussels spread in different types of lake conditions will be valuable for predicting the severity of infestations in lakes across the state, and the impacts they may have on water quality,” said MCWD AIS Program Manager Eric Fieldseth. “This is new information in the field of zebra mussel research.”

The long-term impacts of zebra mussels on Lake Minnetonka are not yet known. As water quality changes in some bays, they could alter the food web which support fish communities and other aquatic life. Changes in algae communities could also lead to more harmful blue-green algae blooms. The native mussel population is also at risk. In parts of the lake, native mussels are being suffocated by their invasive cousins.

“Lake Minnetonka is a uniquely valuable place to study the effects of zebra mussels because of the diversity of water quality, depths and lake bottoms among its numerous bays,” said MCWD Director of Research and Monitoring Craig Dawson. “The findings are extremely valuable in helping inform future lake management decisions.”

The District plans to gather additional data as part of this study. It will increase the number of monitoring sites on Lake Minnetonka to assess the long-term impacts of zebra mussels.

For more information about MCWD’s AIS Program, visit www.minnehahacreek.org/AIS.

Sponsored by: Wayzata Real Estate, for all of your property buying and selling needs in 55391 and School District #284. By the way, know someone ready to buy or sell? I’m never too busy for your referrals! Dan (952) 473-1000.
KSTP5: Big Island underwater trash may turn sandy lake bottom into zebra mussel habitat

September 30th, 2014
Zebra mussels spreading quickly

July 5th, 2011
Unscientific survey finds them on 1 out of every 2-3 rocks in Wayzata Beach swimming area

Zebra mussels growing on a rock found in the Wayzata Beach swimming area this weekend. Photo Dan Gustafson.

Many local families spent time swimming and boating in Lake Minnetonka this holiday weekend. My family spent several days swimming, playing and picnicking at Wayzata Beach. To our dismay, we discovered zebra mussels. Lots of zebra mussels. A lot more zebra mussels than I thought we would find during the first summer with the invasive species.

Sponsored text ad:
Lake Minnetonka Window Cleaning
Sparkling clean windows. Guaranteed.
952-200-1198

Our unscientific survey went like this: walk out past the initial rocks on Wayzata Beach, to water that was higher than waist deep, pick up a rock, and evaluate. Our results were surprising: we found that just about every other rock had a zebra mussel, or two, or three, or more on them.

Zebra mussels on a rock at Wayzata Beach. Photo Dan Gustafson.

The questions for the Lake Minnetonka community:
- How quickly is the first wave of zebra mussels going to grow from babies to adults?
- How quickly are they going to spread?
- What can be done at local beaches if zebra mussels live up to their reputation and grow on every hard surface in the lake?
- Is this going to make it impossible to swim without protective footwear?
While I don’t have the answers to questions, I sure admire the problem.

Five zebra mussels on a rock at Wayzata Beach. Photo Dan Gustafson.

A pile of rocks at Wayzata Beach with any number of zebra mussels on them. Photo Dan Gustafson.

Have some insight into zebra mussels around the lake, or in the area? Found some at your beach? We would love to hear from you. Email wayzata@gmail.com or use the comment box below.
DNR urges extra precautions for Prior Lake

April 14th, 2009

From the MN DNR:

A recent discovery of zebra mussel shells in Prior Lake means boaters and anglers should take extra precautions when using the popular southwestern metro lake, according to officials from the Minnesota Department of Natural Resources (DNR). Although officials aren’t certain whether the shells originally came from live zebra mussels in the lake or were brought to the area on equipment and fell off, they said it’s likely the lake is infested.

After a homeowner reported finding unusual looking shells along the southeast shore of lower Prior Lake, DNR biologists found about a dozen empty zebra mussel shells. DNR staff will look for zebra mussels in Prior Lake as soon as ice is off the lake and will designate the lake as infested if live zebra mussels are found.

A nonnative invasive species, zebra mussels pose serious ecological and economic threats to Minnesota’s lakes and streams. Heavy infestations can kill native mussels, may impact fish populations, can interfere with recreation, and can increase costs for industry, including power and water supply facilities. Native to Eastern Europe and Western Russia, zebra mussels were first discovered in Minnesota in 1989 in the Duluth harbor. They subsequently have spread to eight inland lakes, including Mille Lacs, and to portions of the Mississippi, St. Croix and Zumbro rivers.

If the presence of zebra mussels is confirmed in Prior Lake, it could pose risks for other waters, said Luke Skinner, supervisor of DNR’s invasive species unit.

“As one of the larger lakes in the Twin Cities metro area, Prior Lake has significant boat traffic, with people coming and going all the time,” Skinner said. “Everyone is going to have to be extra vigilant to keep from spreading these pests to other waters.”

Boaters can help prevent further spread of zebra mussels and other invasive species by taking a few simple extra precautions:

* inspect and remove all visible aquatic plants, animals and mud from boats, trailers and equipment such as anchors before leaving a water access;

* inspect and remove all visible aquatic plants, animals or mud from docks, boat lifts and swim rafts before transporting to another water;

* drain all water from boats – including live wells, bilges and bait buckets – before leaving a water access;

* spray or rinse boats with high pressure and/or hot water, or let them dry thoroughly for five days before transporting to another water.

The DNR steps up inspections, enforcement and education around infested waters. Under Minnesota law it is a misdemeanor to transport water or prohibited invasive species from designated infested waters.

a2a_linkname=”Wayzata.com”;a2a_linkurl=”http://www.wayzata.com”;
STAR TRIBUNE: Zebra mussels may have spread to Prior Lake

April 11th, 2009
The Star Tribune is reporting that Zebra Mussels might be in Prior Lake. As an avid boater on Lake Minnetonka, one of my big fears is that they will spread to Lake Minnetonka. In fact, my fear is not a question of if, but a question of when. Nothing kills zebra mussels, and there is hardly anything that can be done to stop them from spreading. They grow prolifically on everything in the water.

When I was a lifeguard at Covenant Harbor Bible Camp and Retreat Center in Lake Geneva WI in the summer of 1997, zebra mussels had just started to take hold. People had to wear aqua socks to go swimming to keep their feet from being cut up. They had not yet started to attach themselves to the boats and docks in countless numbers. They have now been fully entrenched and while Geneva still gets used, it is not the same.

The Great Lakes have suffered from Zebra Mussels for years. Here is a piece from Cecil Adams that describes the challenges Chicago is facing with Zebra Mussels in Lake Michigan. He breaks down the increase in water clarity, but the challenges of living with zebra mussels.

Here are the results if and when they arrive:
- Zebra Mussels on every hard surface in contact with the water, including rocks, piers, boat lifts, boats, docks, and washed up on the beaches.
- Increased water clarity
- Increased algae blooms from Zebra Mussel feces
- Aqua socks to go swimming so that feet aren’t cut up by the razor sharp shells
Whatever can be done to keep them out, I am fully on-board for it. You should be too.

If you have been in a Zebra Mussel infested lake, consider staying out of Minnetonka. It’s not just the visible mussles that will bring them in, but the babies that are undetectable with the human eye and feel like a grit of sandpaper on the hull of your boat. Even just one will change our beautiful Lake Minnetonka forever.

a2a_linkname=”Wayzata.com”;a2a_linkurl=”http://www.wayzata.com”;