Invasive species change Minnesota lakes

Posted at 11:18 AM on January 13, 2012 by Dan Gunderson (0 Comments)
Filed under: Environment, Lakes, Water

MPR Photo/Dan Gunderson

Aquatic invasive species are drawing a lot of attention in Minnesota. Invasive plants like Eurasian milfoil have been common in Minnesota lakes for years. But new invasive species like zebra mussels and Asian carp are causing a higher level of anxiety about their effects on Minnesota's beloved lakes.

Many invasive species arrived via Great Lakes shipping. The U.S. Geological Survey has identified more than 136 exotic species that have established populations in the Great Lakes.

That's how the zebra mussel arrived. This animation created by the U.S. Geological Survey shows how the invasive invertebrate spread.

Geological Survey officials say once an exotic species is established, control efforts are very expensive and rarely successful. Just one invasive, the zebra mussel, is expected to cause billions of dollars in economic effects over the next decade.

Invasive species often have a variety of impacts on the ecosystem.
The zebra mussel, for example, is a filter feeder. That means each mussel filters up to a gallon of water a day, eating the plankton at the bottom of the food chain.

That means less food for some species of fish.

It also means increased water clarity in lakes. In Lake Erie for example, water clarity increased from a few inches to 30 feet as a result of zebra mussel filtering.

Light then penetrates deeper, and aquatic plants grow much larger. That's good for some species of fish like the northern pike, or bass, but all that weed growth hampers boating or swimming in lakes, and can reduce the lakes ability to support fish populations over time.

I often hear people say zebra mussels have no natural predators in Minnesota. That's not the case — Geological Survey officials say there is evidence migrating waterfowl have changed their flight patterns to feed on zebra mussel colonies.

Fish like sturgeon, catfish, freshwater drum and sunfish all eat the tiny zebra mussels.

But the mussel is so prolific, its population generally grows rapidly, despite predators.

Scientists say preventing the spread of zebra mussels is the only effective control. There are chemicals that will kill zebra mussels, but they're mostly used in small areas such as around water intake pipes.They have not successfully been used to treat an entire lake.

The state Department Natural Resources has experimented with pesticides to control an early infestation of zebra mussels. But the verdict on that approach is not in.

Minnesota officials are focusing on prevention with expanded boat inspection and decontamination. The state is also requiring workers who move equipment like docks and boat lifts to be trained to recognize aquatic invasive species.

Zebra mussels are commonly thought to hitch a ride from lake to lake on boats, but can just as easily travel on the boots of someone who goes from lake to lake installing or repairing docks, or on the gear of scuba divers or swimmers.

Listen to my report on how Minnesota lake associations hope to spur action against invasive species on today's All Things Considered.

Comment on this post

Invasive species aren't always pests

Posted at 12:03 PM on December 1, 2011 by Dan Kraker (4 Comments)
Filed under: Around MN, Arrowhead, Environment, Research, Water

The havoc that aquatic invasive species like zebra mussels have wreaked on the Great Lakes and beyond has been well documented. They reproduce faster than rabbits, suck up plankton off lake floors, starving native species, and clog water intake pipes.

Zebra mussels, along with nasty critters like sea lamprey and those great flopping river acrobats Asian carp, have given invasive species a bad rap -- often very deservedly so. But new research suggests that the most recent Great Lakes invader may actually help their new home.

The "bloody red shrimp" was discovered in Lake Michigan in 2006. They've spread to all of the Great Lakes except Lake Superior. Like zebra mussels, they likely hitched a ride from the Black and Caspian seas in eastern Europe in the ballast tanks of ocean-going freighters. Requirements for ships to exchange ballast water at sea have since slowed the introduction of non-native species to the Great Lakes.

New research shows that the little crustacean, so named for its bright red spots, has become food for native species like yellow perch and alewife.

Mike Yuille, a graduate student at Ontario's Queens University, tells UPI that "forecasting how an invader will affect the growth and production of a specific native fish species is very relevant to conservation groups and government agencies hoping to conserve those fish." Yuille's findings will be published in the Journal of Great Lakes Research.

But the relationships among native and non-native species are complex. Yuille's research also suggests that round gobies have incorporated the shrimp into their diet. Gobies are another aquatic invasive species, also brought over to the Great Lakes from far eastern Europe in ballast water.

Comment on this post

Leech Lake tribe moves forward with new water treatment plants

Posted at 3:16 PM on November 4, 2011 by Tom Robertson (0 Comments)
Filed under: Northwest Minnesota, Tribal issues, Water

The Leech Lake Band of Ojibwe is making progress on serving more tribal communities with municipal water treatment plants.

A plant came on-line this week that will serve residents living in a neighborhood known as Tract 33, adjacent to the City of Cass Lake. About 60 percent of an estimated 280 homes are already hooked up to the water system. The rest will be connected next spring, according to Tribal Engineer John Fairbanks.

Until now, those homes have been served by a combination of individual wells, small cluster systems and one larger public water system, none of which provided residents with treated water.

"It's been a high priority for the reservation for quite some time," Fairbanks told the Bemidji Pioneer.

The system cost nearly $4.2 million, and includes funding from the U.S. Department of Agriculture and the U.S. Army Corps of Engineers. Planning on the project began 10 years ago.

The new system includes about 10 miles of pipe and a 250,000 gallon elevated tank.

The Leech Lake Band is expected to complete a similar water treatment project next week in the tribal community of Inger.

Comment on this post

Mother nature a bigger problem than farmers for Sauk canoeists

Posted at 10:26 AM on June 23, 2011 by Michael Olson (0 Comments)
Filed under: Rivers and streams, Water

By Alison Dirr

Map of obstructions along the Sauk River

View Sauk River in a larger map

Eight days after they departed from Lake Osakis, Scott Miller and Todd Foster reached their final destination having encountered far fewer fences than they had predicted.

Background on the trip.

"There was probably six that were across the river," Foster said. "[The number] was significantly lower than we thought and most of those were right away in the first half mile, three quarters of a mile in the river."

He added that they saw around a dozen fences that he believed had once crossed the river. These fences reached to the banks but did not block the waterway.

Adam Hjelm, education coordinator for the Sauk River Watershed District, was part of a SRWD group that canoed the upper Sauk in 2008. He estimated that they encountered about 30 fences between Lake Osakis and Melrose.

Hjelm and Foster noted a number of possible reasons for the disparity.

According to Hjelm, farmers often do not pasture their cattle around the river until later in the summer after other pastures have been depleted. As a result, he said, many farmers would not have put their fences across the river yet.

He also said that Foster and Miller may have passed right over some of the lower fences because of high water levels this year.

Foster also noted that an accident last year on the river may have prompted farmers and landowners to rethink their use of fences.

"Maybe because of that girl that got hurt last year farmers and landowners were talking amongst themselves and decided that, 'Oh hey, this is not good if people get hurt and we're going to be liable for the injuries,'" he said.

According to Foster, neither the SRWD or the Department of Natural Resources has reached out to landowners on an individual basis to address the fencing issue. If they were removed, he said, it was entirely the landowners' prerogative.

Tell us about Minnesota's river and streams We want to know about the rivers and streams that you know best. Which are in the best condition? Which ones have problem spots? Share your observations here.

But fences are not the only concern to paddlers, he said. The DNR is responsible for removing fallen trees, which are especially noticeable in the upper Sauk.

"Certainly the second day, the second seven miles there was very little fences across but it would be very difficult for the average paddler to make it through because of all the snags and trees across the river," he said.

Foster and Miller used GPS technology to catalog the barriers in the river and planned to relay their findings to the DNR. The travelers have not been in contact with the DNR since they returned from their trip.

Comment on this post