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St. Anthony lock to be closed against carp

McClatchy-Tribune photo

MINNEAPOLIS — Fear of a fish will bring an end to continuous navigation on a portion of America’s greatest river.

In an effort to prevent the advance of invasive carp, Congress appears poised to close the Mississippi River shipping lock at Upper St. Anthony Falls in Minneapolis within a year, Minnesota’s congressional delegation announced Tuesday.

The closure, which could happen as soon as Memorial Day, won’t be a done deal until both the House and Senate approve a larger water infrastructure bill and the president signs it. That outcome, once seen as a political long shot, now appears likely after bipartisan members of the proposal’s conference committee agreed to it.

The carp — silver and bighead carp often called “Asian carp” — are voracious feeders of plankton and can undercut an entire ecosystem, imperiling a range of native fish. A shipping lock, which is essentially a water elevator for boats, can allow the fish to gain access to waters above a dam, so closing the lock is seen as one of the most effective barriers to prevent the carp from invading farther upstream.

Thus far, the fish aren’t known to have established themselves in Mississippi River waters in Minnesota, but they have been advancing, and carp eggs were found this winter in the river below Lock and Dam No. 8 in Genoa, Wis., so they’re finning at the doorstep. Many biologists believe if carp establish themselves, they’ll be nearly impossible to eradicate.

The congressional action was spearheaded by U.S. Sen. Amy Klobuchar, who attended several “carp summits” convened by Gov. Mark Dayton.

“The spread of invasive carp poses a major threat not only to Minnesota’s environment, but also (to) the recreation and fishing industries that help power our state’s economy and create jobs,” Klobuchar said in a statement. She was joined by Sen. Al Franken, and Reps. Keith Ellison, Erik Paulsen, Tim Walz and Rick Nolan.

Closing the locks, scientists say, should bring security to waters upstream, although it’s not the only protection.

Work is expected to be completed this year on a rehab of the Coon Rapids Dam that will make it a more effective barrier, though fish still could swim past the structure during severe floods. Above Coon Rapids lies the Rum River, the outlet of Lake Mille Lacs, one of the state’s most important fishing lakes.

A number of dams farther upstream on the Mississippi probably would hinder the fish’s advance through the heart of Minnesota’s fishing and boating waters toward the river’s headwaters of Lake Itasca.

The closure of the lock is expected to raise a question of what will become of more than $10 million the DNR was moving forward with spending to build an electrical, light and sound barrier below the Ford Dam in St. Paul, also known as Lock and Dam No. 1.

Many observers believe the key battles against the invaders must be fought in southeastern Minnesota before the fish have access to the Minnesota River — believed to be prime habitat for bighead and silver carp — and the St. Croix River.

“Closing the lock is really helpful for all the waters above St. Anthony Falls,” Clark said. “But for all the waters below the falls, this does nothing. We still have a lot of work to do.”

The Pioneer Press is a media partner with Forum News Service.