Stun, collect, study: electro-fishing advances understanding of fish populations in Northwoods lakesSubmitted: 07/31/2015
Ben Meyer
Ben Meyer
Managing Editor / Senior Reporter

Stun, collect, study:  electro-fishing advances understanding of fish populations in Northwoods lakes
BOULDER JUNCTION - The boat looks like something from a science fiction movie as it creeps across Northwoods lakes at night.

Its long arms jut into the water, sending electrical pulses into the lake.

Under a nearly-full moon on a warm July night, it motors across Sparkling Lake in Vilas County.

"We can actually sneak up on them in the evenings, when it's dark out," says Dr. Noah Lottig, who's driving the boat. "They're up there, they don't see us coming, and we can sneak up on them."

This is how Lottig fishes. He's an Assistant Scientist at the UW-Madison Trout Lake Research Station in Boulder Junction. The electrical field produced by his boat is the first step.

"It temporarily stuns the fish, allowing us to collect the fish [and] put them in a live well in the boat," Lottig says. "I want to make sure that we have enough [electricity] to stun the fish, but not so much that we have the potential to hurt them."

It's a ritual that Trout Lake Station scientists perform every summer.

"We've been doing this for 30 years," Lottig says.

As part of the Long Term Ecological Research program, scientists record information on the fish they stun and collect, helping to find trends in population, diversity, and fish health.

"We're interested in understanding long-term change in lakes," Lottig says. "One of the things that we study is long-term change in fisheries communities."

Lottig, helped by a handful of undergraduates on board, sticks to routes near the shore of Sparkling Lake. At night, fish tend to gather in this area. As the boat passes over them, the electrical field stuns them for a moment. Two undergraduates wait in the front of the boat with nets on poles.

"If you see a fish, get it, grab it right away, as fast as you can, and pull it out," Lottig instructs them.

Their opportunity is short.

"(The fish) recover remarkably fast. Sometimes seconds," Lottig says. "There's very, very low mortality. I've been doing this five years, and it's at least three or four years since we've lost a fish doing this, so our mortality is extremely low."

After 30 minutes, Lottig's team carefully records the length and weight of their catch. The team collects scales from some of the fish. He fishes for three sessions of 30 minutes, and collects everything from panfish to smallmouth bass to perch before throwing them back.

The information they record goes into the long-term record of Sparkling Lake. In this particular lake, for example, scientists have been able to track the decline and subsequent rise of panfish populations. It seems to be directly connected to the influx, and later eradication, of the invasive rusty crayfish.

Monitoring trends like this is only possible through this odd-looking endeavor, electo-fishing at night in the Northwoods.

"We got a wide range of species. A couple of the runs, we got a lot of them," Lottig reviews. "We got what we were looking for."

Text Size: + Increase | Decrease -
| Print Story | Email Story
Sponsored in part by HodagSports.com


Play Video

CONOVER - June 22 makes it the 14th day of rainfall for us this month, and it's not been very convenient.

People all over northcentral Wisconsin have had to deal with storm damage or flooding in some way.

Pioneer Lake in Conover has had a particularly tough time with flooding not only because of the rain, but also because of a dam upstream.

"We've got 20 piers here, and they're floating away, they're underwater," said Maple View Resort and Campground Owner Tony Osiecki. "I've never seen it like this in fifty years."

Osiecki blames the deluge of rain we've gotten in the past few weeks for the flooding in his resort. But he and many others on the lake also blame a dam upstream.

+ Read More

Play Video

LAC DU FLAMBEAU - Thursday, volunteers faced mosquitos, ticks and rain to conserve 96 acres of land.

The Marshall Wildlife Conservation Center in Lac du Flambeau hosted a volunteer work day to dismantle a deteriorating pier and platform on a new conservation land donation.

Northwoods Land Trust Executive Director Bryan Pierce says the land has a creek and pond with many swans and beavers.

"We're going to be installing a brand new pier, so it will be a real nice wildlife observation area for people to look at the water, the swans and cranes," said Pierce.

+ Read More

Play Video

RHINELANDER - Bill Makris taught P.E. at Rhinelander High School for 30 years. But he's since shifted his time to teaching summer camps.

"These are kids that want to be here," said Makris.

The camps aren't your typical workshops or outdoor activities.

"Strength training, speed development, agility," said Makris.

He helps younger kids concentrate on attainable athletic goals.

"I do like running track and cross country so I want to increase my speed ability," said Rhinelander 8th grader, Sage Flory.

+ Read More

Play Video

RHINELANDER - Hodag Park received a sizable donation Thursday morning. New sand was dropped off to help the Rhinelander Parks Department grow the beach back to its original shape.

There were thousands of pounds of sand dropped off and spread out. There was a high need for this because of all the rain we've had this season.

"It was getting in pretty poor shape and washing out more and more, but this year especially, it just seems like we've lost a lot of sand. So now we're going to shape it up nicely and hopefully it'll last the year," said Rhinelander Parks Director, Jeremy Biolo.

All of that sand was donated and delivered by a company in Rhinelander.

"Musson Brothers, Inc. donated all the sand and they said we could help ourselves to as much as we want, which is unbelievable because this beach really needed some work," said Biolo. "Every little bit like that helps our community out and it improves the community. It's awesome that the Musson Brothers stepped up and would do that for us."

+ Read More

RHINELANDER - Nicolet College's Motorcycle Basic Rider Course teaches folks to safely hit the road on their bike.

The class is in full swing for the season.

Nicolet College Rider Coach Mike Murray says even experienced riders can use a "safety brush-up" this time of year.

Riders should always wear their helmet, long pants and shirts, gloves, and boots.

It's also important to keep your eyes moving for critters that come out of the woods,especially deer.

"If you know you're going to hit it: let off your brakes, hit it with your handle bars straight ahead looking straight ahead so that your bike stays straight up," says rider coach Mike Murray.

+ Read More

Play Video

MERRILL - One hundred years ago, Finland gained its independence from Russia. As part of Finland's birthday, a sauna will travel the United States.

On Thursday, the traveling sauna stopped in Merrill. Since January, the sauna has been traveling around the country.

+ Read More

GREEN BAY, WI - Firefighters had to rescue a man after his minivan became wedged in a drawbridge in downtown Green Bay.

Officials say the van got stuck between one of the opening spans and the fixed roadway on the Walnut Street Bridge early Thursday.

+ Read More
+ More General News

Click Here