South Fork Shock: Fish research with stunning results

The South Fork of the Snake River is one of the oldest stretches of surveyed water in Idaho and for good reason. What happens on the South Fork says a lot about the whole river system in eastern Idaho. That’s why Idaho Department Fish and Game shocks two miles of the South Fork in Swan Valley every fall.

“It has a good mixture of the species we find in the South Fork. We see brown trout, rainbows and cutthroat trout,” says Brett High, Idaho Department of Fish and Game fisheries biologist. “Since they’re all here and in enough abundance that we can capture them, we can then get an estimate on them. With that estimate, that helps us make management decisions.”

Cutthroat trout, beefy browns and line-ripping rainbows go belly up when electricity enters the water. The fish are stunned just long enough for scientists to net, measure and tag the flippers before sending them back into the river.

Electrofishing is done by the department over a few days every October. The results take weeks to tally, but you can bank on thousands of fish from bank to bank when the results come out. How those thousands break down by species is the variable on an annual basis.

Outdoor journalist Kris Millgate is based in Idaho Falls, Idaho. See her work at www.tightlinemedia.com