Content as most Minnesotans are to wait near the top of the Mississippi River drainage and hope that invasive Asian carp don’t arrive this far north anytime soon, Mark Ellenberg for many years has done the opposite: He’s hunted them down wherever they are and tried to kill them. ¶ Ellenberg and I were talking about this the other night in the dark, on the St. Croix River, not far from the Allen S. King power plant in Bayport, where five bighead carp were caught recently, some by fishermen, others by the Department of Natural Resources (DNR). ¶ By about 7 miles, it’s the farthest north bigheads have been captured in the St. Croix. ¶ Their arrival shouldn’t have been a surprise, said Ellenberg, 47, of White Bear Lake. ¶ “Ten years from now, there’ll probably be a lot of them,” he said. ¶ As he spoke, he stood in the bow of his 27-foot custom-made bowfishing boat, one hand on the electric trolling motor that pulled the craft forward, the other on a compound bow, an arrow nocked.

He’s used the same equipment to kill bighead carp in South Dakota, Illinois and Iowa. Forays to these distant locales sometimes have been for challenge and enjoyment, other times to compete in bowfishing tournaments.

How invasive can invasive carp be?

“In one tournament on the Illinois River, my partners and I won by bringing 5,500 silver carp to the dock in 12 hours,” Ellenberg said. “This was a ‘by any means’ tournament, so about 20 percent of the carp we shot, while the others jumped in our boat as we ran down the river.”

Known for their acrobatic leaps when startled by the underwater whine of boat motors and other disturbances, silver carp might represent the biggest threat of all invasive carp to aquatic habitats and fisheries, and to water sports.

Bigheads and grass carp, meanwhile, are in many instances the pioneering species, the ones that arrive first.

Bigheads like those caught near Stillwater last week are challenging to locate and even more challenging to kill, Ellenberg said.

“Bigheads are among the most sensitive fish there are,” he said. “That’s why the DNR and others who have tried to net them usually don’t come up with anything. Bigheads accept almost no disturbance. Any boat noise or motor noise and they’re gone.”

In South Dakota, near Yankton, Ellenberg was among the first bowfishermen to hunt bigheads on the Missouri River. This was in the 1990s, and sometimes he and his friends sought the big fish in daytime, other times — as he and I did the other night on the St. Croix — after dark.

Native to Asia, bighead carp, like their invasive buddies, silver, grass and black carp, can wreak havoc with native fish and their habitats. Some feed on native mussels and snails, while others simply outcompete other fish for food while altering entire aquatic ecosystems, including plants, invertebrates and fish.

The largest bighead taken by bowfishing was killed in the Mississippi River near Alton, Ill., in 2008. The fish weighed 92.5 pounds.

Challenging as they are to hunt, bigheads, Ellenberg said, sometimes give their positions away in shallow water by making slight surface indentations with their mouths. Unless a person knows specifically what to look for, he’ll miss it.

“One way we get them at night, once we locate one, is to turn off all of our lights and drift or — as quietly as possible — move into position with the electric trolling motor,” Ellenberg said. “Then, if there are two or three of us in the boat, we’ll all be on the bow, and when we’re in position, we’ll hit the lights and shoot.”

Long practiced in the South, bowfishing is enjoying greater popularity north of the Mason-Dixon line, including in Minnesota, where laws passed recently allow the sport to be practiced at night.

Ellenberg, who grew up in West St. Paul, first shot rough fish as a kid, after reading a bowfishing story in Sports Afield magazine. A past president of the Bowfishing Association of America, he also was a co-founder of Land of Lakes Bowfishing Association, Minnesota’s largest bowfishing advocacy group.

Each year, Land of Lakes sponsors a free bowfishing day for kids that stresses safety, sportsmanship and especially the proper disposal of carp and other fish bowfishers target.

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Bowfishing equipment choices are many.

Sometimes, as in Ellenberg’s case, compound bows specially built for bowfishing are the preferred choice, while other bowfishers opt for recurve-style bows. In either case, unlike in bow hunting for deer, no sights are used.

Instead, bowfishers shoot instinctively by aligning their eyes with their arrows and targeted fish. As they do, they simultaneously draw back their bows and, nearly in the same motion, send arrows flying.

Hitting a target this way requires practice, especially given the refractive nature of water.

“To hit the fish, you have to shoot below it,” Ellenberg said. “The fish isn’t where it appears to be.”

About mid-morning Tuesday, the DNR announced the new finding of bigheads, and by 10 that night, Ellenberg and I were patrolling the St. Croix’s shorelines, the shallow water lit up by the high-powered LED lights that flanked Ellenberg’s big aluminum johnboat.

Because his lights are powered by batteries, Ellenberg requires no generator on his craft, an advantage that allows him to run quietly, perhaps making him more effective, while also minimizing disturbance of property owners.

“We try to be as respectful as we can be,” Ellenberg said.

As he spoke, a carp — this one a common carp, a species that has plagued Minnesota since first being imported here in the late 1800s — darted among submergent vegetation in water perhaps 3 feet deep.

To make a successful shot, Ellenberg had to compute many variables concurrently, including speed of the boat, speed and direction of the fish, and depth of the water.

Thus a bowfisher’s indifference to sights: By the time they could be aligned with a fish, the fish would be gone.

Almost as quickly as he saw the fish, Ellenberg let fly an arrow. Its tip was designed for quick, deep penetration, and once fully impaling a fish, barbs on the tip would open, preventing the arrow from pulling back through.

An arrow is connected to a bowfishing bow by a string that is wound inside a reel attached to the bow.

In this case, the carp escaped unscathed, and we moved on, noiselessly, into the dark.

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The hope in Minnesota and Wisconsin is that black, silver, grass and bighead carp, among other creepy invasive critters, can be discouraged from establishing reproducing populations this far north until scientists figure out a way to repel and/or kill them.

Whether this will happen, or when, no one knows.

Meanwhile, bowfishers fill the void, enjoying sport while performing a sort of public service, killing carp.

When we called it a night early Wednesday morning, a full moon hung high in an otherwise very black sky.

No bighead carp were in our boat. Common carp, yes. But no bigheads.

Another time, perhaps.

As Ellenberg said, “They’re coming.”