Rare is the Minnesotan who has not seen videos of fish leaping out of water and hitting boaters.
Word has spread across the state in the last couple of years about the invading Asian carp seen in those videos and the damage they could cause native fish. But few Minnesotans know the extent of the invasion from outside plants and animals.
In addition to invasive carp threatening native species, the state’s natural resources experts warn of widespread threats from spiny waterflea, buckthorn, zebra mussels, Japanese beetle, earthworms and dozens of other species.
The Department of Natural Resources Minnesota State Fair booth illustrates many of the invasive plants, animals and pathogens threatening Minnesota. The department discusses more than 40 of them on its Web site (http://tinyurl.com/MNinvasive).
Minnesota Natural Resources Commissioner Tom Commissioner Tom Landwehr said it is not a matter of stopping the invasion, it is more an issue about how to slow it down.
Scott Rutledge appreciates the educational approach in an area that especially concerns him. Like other anglers across Minnesota, the Minnetonka man said zebra mussels are a problem.
“They make it hard to be on the lake,” he said as his family looked at a fishing pole encrusted with mussels in the DNR fair exhibit.
His son chipped in that the shelled animals are a pain, literally.
”They are really sharp,” 14-year-old Colton said from experience.
Rutledge said new laws and regulations requiring boat cleaning are good steps. “You just got to do it.”
An active campaign to clean boats before moving them to another body of water has achieved some success in slowing the spread of species such as zebra mussels. But the DNR wants Minnesotans to take similar actions to slow the spread of other invaders, too.
For example, the DNR’s Susan Burks said, hikers should clean their shoes, clothes, vehicle tires and pets before and after their walks. Seeds can adhere to shoe soles, tires and nearly anything else and they can end up where they do not belong.
The DNR has five steps in its “play, clean, go” campaign:
— Clean gear before entering and leaving a recreation site.
— Remove mud and seeds from clothes, pets, boots, gear and vehicles.
— Burn only local firewood.
— Use only local or certified weed-free hay.
— Stay on designated trails.
“We need to make it a habit for everyone,” the DNR’s Jay Rendall said about doing things like cleaning gear.
Even as the fair booth educates people about how to slow the invasion, DNR officials announced this week that Lake Ore-Be-Gone, also known as the Gilbert Pit, in northeastern Minnesota is infested with zebra mussels, the farthest north they have been found.
The mussels, which eat nutrients that native species need, thrive in many Minnesota lakes.
The DNR recently announced that it is working with federal scientists at Lake Carlos State Park, near Alexandria, on using a type of dead bacteria that could safely control zebra mussels.
While it works in some enclosed situations, Rendall and Landwehr had doubts it could be used to treat larger bodies of water.
“There’s a lot of questions,” Rendall said.
It seems that education like that seen at the fair booth is the best defense in this war.
The booth shows that invaders take many shapes and sizes. One insect, a wasp, is so tiny that it looks like a period on a printed sheet of paper.
The booth also shows how difficult it may be for regular Minnesotans to see the difference between invaders and native species. For instance, the native milfoil plant, which grows in water, looks similar to the invasive variety, differing only in the number of leaves.
The most surprising part of the booth for many may be a little display that shows the danger of worms, which most Americans learned in school are good for the soil.
The Great Lakes Worm Watch shows how earthworms are destroying parts of northeastern Minnesota’s forests. University of Minnesota researchers have documented that worms destroy some plants on the forest floor, which could adversely affect other plants and animals.
Burks said that glaciers thousands of years ago killed any worms that lived in Minnesota, and any now in the state have been brought in by humans, intentionally or not.
Minnesota rethinking Asian carp evidence
Announcements that Asian carp DNA had been found in and near the Mississippi River around the Twin Cities sent shutters through Minnesota last October and December.
That could mean, the experts said, that the invasive fish with huge appetites could move into most other Minnesota waters, eating native fish’s food and perhaps severely injuring large recreational fishing and resort industries.
State officials now, however, question those results and Natural Resources Commissioner Tom Landwehr said he expects an announcement soon about new tests that could show the DNA may not have come from Asian carp in the Twin Cities.
Landwehr, talking in a Minnesota State Fair invasive species exhibit, said water has been retested, but did not go into details about what was found.
The environmental DNA tests have been controversial, and even the Notre Dame University scientists, former and present, who developed the tests say they do not prove fish are in the area where they find strands of carp DNA.
Jay Rendall of the Minnesota Department of Natural Resources said that Asian carp DNA may have got into Mississippi water in any of a number of ways, without fish actually being there. Birds could deposit it, fish feces and urine may have somehow got into the river or just fish scales could produce the results.
Still, live bighead carp have been caught in the Mississippi south of the Twin Cities and in April a 30-pounder was caught in the St. Croix River where it dumps into the Mississippi. Bighead is a species of Asian carp.