Throughout the Northern Rockies, one type of Easterner has worn out its welcome. The brook trout, a freshwater fish that populates the streams of the Eastern U.S., Wisconsin and Michigan, has been busy swamping large areas of Montana, Idaho and other Western states.
Anglers love catching brook trout, but its success in its adopted region has come at the expense of native cousins like the cutthroat trout. Brook trout have been such tough competitors for resources, in fact, that native fauna have been significantly reduced or disappeared entirely from some waterways.
To combat the invasion, fishery managers typically apply chemicals called piscicides, which are highly toxic to all aquatic life including fish and insects. Though effective at controlling non-native species and the damage to the ecosystem is thought to be relatively short-lived, many see this technique as a sledgehammer tool where a scalpel is needed.
Now ecologists with the Wildlife Conservation Society, Montana State University and other organizations say they have found a more targeted way of clearing brook trout from streams. Instead of chemicals or mechanically harvesting brook trout, they have found that a technique called electrofishing can eradicate the fish from streams while leaving other species alone. They also found that electrofishing would cost about the same as using piscicides.