Notes from the Northwoods: Electrofishing on Allequash Lake

This summer, Anna Krieg, an undergraduate at Arizona State University, will spend a few months in a much wetter habitat as the CFL’s summer outreach intern at our Trout Lake Station. Enjoy her Notes from the Northwoods:
by Anna Krieg – Just as the sun is setting over the trees at Trout Lake Station, Martin, Ellen, Amien, and Jim all meet by the massive electroshock boat and drive out to the lake where they will be electrofishing tonight.

Martin Perales and Ellen Albright plan their root for the night's electrofishing as Jim Miazga looks on. Photo: Anna Krieg
Martin Perales and Ellen Albright plan their route for the night’s electrofishing as Jim Miazga looks on. Photo: Anna Krieg

Electrofishing is a common scientific survey method used to sample fish populations to determine abundance, density, and species composition. A boat, dangling long tendrils into the surface of a freshwater system, uses an on board generator to apply electric current to the water to collect fish. The electric field created does not kill the fish, but temporarily stuns them. The technique allows the fish to be scooped up and handled with less stress and injury sustained than if they were pulled thrashing into the boat. Martin operates the generator and maneuvers the boat skillfully near the edges of the lake where fish tend to hang out and, especially, where predators tend to follow prey toward shore when the sun goes down.
Ellen and Amien stand at the front of the boat with giant nets ready to catch any fish floating to the surface. Jim stands behind to empty the nets into a pool, where the fish will be stored until they can be measured and weighed. Tonight the goal is to measure and weigh as many fish as possible in four separate locations on Allequash Lake.
Amien Paust measures the length of a fish caught during electrofishing. Photo: Anna Krieg
Amien Paust measures the length of a fish caught during electrofishing while another fish waits in the holding tank. Photo: Anna Krieg

This was my first time witnessing electrofishing in action. I was surprised not only by the amount, but also the variety of fish caught. Each run through our four locations yielded dozens of fish from little minnows to walleye to bluegill to large and smallmouth bass. As each fish was weighed and measured, I noticed everyone falling into their role.
Amien, who is still learning how to identify the fish that live in the Northern Lakes region, would measure the fish and call out his best guess as to what it was. Martin would write down the measurements and weights, while double-checking Amien’s identification. Ellen weighed the fish and released them safely back into the water. Jim surveyed the scene, offering his expert fish identification knowledge whenever everyone was stumped. I was lucky enough to sit back and watch, learning from everyone else as they explained things like the different markers of fish, the time of year different species spawned, and the number and type of spines.
As an added bonus, we couldn’t have picked a more beautiful night to be on the water. It was cold and clear and we had millions of stars overhead to keep us company.