Exhibited on the sixth floor of the Department of Natural Resources headquarters Thursday afternoon was a mounted silver carp, a fish perhaps 2 or 3 years old, and one that, as a species, presents a clear and present danger to Minnesota waters, not least the St. Croix River, where special tests conducted in June for the first time suggest -- the DNR's parsing -- the presence of these leaping villains.

Chances are that suggestion will become a statement of fact in coming weeks as the DNR deploys commercial fishermen as well as its own staff in an attempt to catch a silver carp, thereby confirming what has long been feared: that these jumping missiles have made their way upstream to Minnesota. And Wisconsin. If true, tributaries such as the Apple River, which enters the St. Croix from the east, also are threatened, as are other adjoining waters.

Similar Mississippi River tests -- called eDNA -- conducted in June from the Ford Dam downstream to the Minnesota River found no suggestions of the presence of Asian carp, the DNR and National Park Service said. But the chance is better than even that the high, turbid water that prevailed during that testing masked the presence of Asian carp in that stretch of the big river.

A creature that wasn't discussed at the DNR on Thursday, but was present at the news conference nonetheless, was the elephant in the room. Namely, that invasive species such as round gobies, spiny water fleas, zebra mussels, Eurasian water milfoil or the much feared (and not here yet) snakehead, as well as Asian carp, are overwhelming the DNR.

Make that have overwhelmed the DNR. And if legislators don't act soon to boost Minnesota's defenses against these critters, the state will be overwhelmed by them too.

True, in its past session, the Legislature hiked DNR funding by a few million bucks a year, over two years, to fight invasive species. And wouldn't it be nice if that would be sufficient to purchase boat decontamination units for assignment statewide, pay for watercraft inspectors at more public and private launch sites and supplement the pay of conservation officers whose new and updated list of never-ending duties now includes invasive species enforcement, Asian carp to zebra mussels?

But it's not nearly enough. What's needed instead, or in addition, is Big Thinking. Or at least thinking and action proportionate to the size of the problem.

Perhaps a sufficiently staffed Invasive Species Division should be added to the DNR.

Or maybe an existing DNR division should be reorganized, drawing experts from fisheries, ecological and water resources and other divisions and bureaus, as needed. And adding more.

Or perhaps a state invasive species agency unto itself should be formed, not only so it can more effectively implement Minnesota's defense and eradication policies, but so it can dedicate the time and resources necessary to marshal the citizenry in the fight against both aquatic and terrestrial interlopers.

This last will be critical going forward. Right now, lake associations from Detroit Lakes up north to Christmas Lake in the metro to Green Lake out west want to do more to keep their waters as monster-free as possible. But their much-needed efforts often can't be leveraged fully by the DNR because the agency has too few people in the invasive species fight, with too few resources.

At Thursday's press conference, a coalition of environmental and conservation groups issued a statement decrying the "years of ignoring the threat posed by Asian carp," and noting the Army Corps of Engineers should consider closing the locks at the Ford Dam and the St. Anthony Falls Dam to keep carp from moving farther north.

And the DNR said it might support construction of a bubble or sonic barrier to thwart upwardly swimming Asian carp at Prescott, Wis. -- a long-overdue action.

Here's a somewhat bigger idea for the to-do list:

At Lock and Dam 19 on the Mississippi, at Keokuk, Iowa, electric barriers similar to those being used effectively in Chicago to keep Asian carp out of Lake Michigan should be installed.

The barriers cost about $7,000 a year to operate, according to National Park Service officials. But they would provide an effective strategy to isolate Asian carp problems upstream, leaving Minnesota and Wisconsin officials, together with the feds, the perhaps-manageable task of eradicating fish already here.

Or, we can keep on doing what we're doing. Which isn't enough.

Dennis Anderson • danderson@startribune.com