Electrocution Stun Guns May Save Montana’s Native Trout
How do you get rid of invasive fish in streams while minimizing harm to native species?
Zap ’em all.
Electrocuting fish can save Montana’s native trout from being overrun by invaders from the East, according to a new study published in the North American Fisheries Journal.
Here’s how it works. Start with two land managers from the Montana Department of Fish, Wildlife and Parks wading through streams in the upper Missouri River basin. One is armed with a net, and the other carries what looks like a Ghostbusters backpack.
The “backpack shocker” contains a battery that sends a current to a wand held by the ranger. As the ranger sweeps back and forth through the streams, the jolt of electricity temporarily stuns the fish. That gives the net-wielding ranger time to snatch up invasive brook trout while returning the native westslope cutthroat to the stream—mostly unharmed.
After a short while, the stunned native trout are back on their fins, swimming in streams now free of brook trout, a fish introduced from the eastern United States and Canada. Populations of westslope cutthroat—Montana’s state fish—have plummeted as nonnative fish have taken over their habitat.
Bradley Shepard, a biologist at the University of Montana and the study’s lead author, believes that “electrofishing” can replace more conventional eradication measures such as poisoning, which kills native and invasive fish alike.
Piscicides—pesticides that target fish—can wipe out nearly all aquatic life. While that’s great for destroying the nasty invasive northern pike in places such as California’s Lake Davis, it’s not a good way to preserve westslope cutthroats.
“Piscicides are a valuable tool to remove non-native fish,” Shepard said in a statement. “But where non-native and native fish coexist in smaller streams, a potential alternative method, electrofishing, can be used to remove specific unwanted species, while reducing impacts on WCT [westslope cutthroat trout] or other native fish and macro-invertebrates.”
More than 9,500 invasive brook trout have been eradicated by electrofishing in four out of the six test streams, according to the study.
The researchers found that electrofishing can be as cost-effective as piscicides as long as vegetation and brush don’t hinder its use.
“This is an attractive alternative, particularly in situations where populations of native fish live in the same location as non-native fish as electrofishing will allow for the preservation of the native fish,” the researchers wrote.
Related stories on TakePart:
• Meet 6 Monster Fish That (Believe It or Not) Live in Our Rivers
• Shocker! Half of U.S. Rivers Too Sick for Fish to Live in
• The Return of the Colorado River to the Sea
Original article from TakePart
