Electrofishing with the DNR On Lake Superior Near Grand Marais
A team of fisheries biologists and researchers from the Minnesota Department of Natural Resources recently spent the better part of a night looking for coaster brook trout near the Grand Marais Harbor.
Their work on Lake Superior involved using non-lethal electric currents that were delivered from a research vessel into the water.
The purpose of literally electrocuting fish is to learn more about what various species are eating in Lake Superior near Grand Marais. They also want to track numbers of protected coaster brook trout, a native species to these waters. All of the fish surveyed, including brook trout, steelhead, rainbow trout, burbot, and whitefish, will be released back into Lake Superior.
An electrofishing boat uses a generator to produce electricity. The electricity travels to the poles, called booms, at the front of the boat and into the water. The electric field does not kill fish but temporarily stuns or impairs those that swim within a 6- to 8-foot radius from the booms, according to EJ Issac, the Grand Marais area fisheries supervisor for the DNR.
The electric current and its effect on the fish in Lake Superior are typically minimal. If done properly, this sampling technique can be much less damaging than methods that entangle or trap fish, which may injure or even kill them, Issac says. It is illegal for anglers to use electricity to fish.
The fish are in close, near the Grand Marais Harbor and about two miles east of town. The loud beeping from the electric system provides a constant melody as the research team moves from east of Grand Marais closer to the harbor. The species of greatest interest to the biologists is coaster brook trout. After an hour or so of collecting fish, they’re mostly finding steelhead and smaller rainbow trout, which isn’t a bad thing, Issac explains.
After the first round of sampling is done, Nick Peterson and Nate Beckman from the DNR pump the stomach of the fish using water to flush the contents. They find all manner of insects and partially-digest fish in the stomach of the 22-inch steelhead.
Though the researchers on this particular phase of the project were from the DNR, Issac says that collaboration on this research with the Grand Portage Band of Lake Superior Chippewa is extremely important.
In this week’s episode of the Outdoor News Podcast, we learn more about the experience, including an audio report from the harbor and on board the boat where the electrofishing took place.