Electrofishing the McKenzie River

Electrofishing the McKenzie River »Play Video
"I once shocked a fish THIS big ...": Oregon Department of Fish and Wildlife biologists use electrofishing to stun fish and examine them before releasing them back into the river.

SPRINGFIELD, Ore. - It’s a beautiful sunny morning on the McKenzie River in Springfield, Oregon.

The shores are wild with strands of light green moss that hang from outstretching tree branches and all is quiet except for birds chirping and the flow of the cool, deep water.

Here, the Oregon Department of Fish and Wildlife is setting up for some of the first fieldwork of the season: they’re going electrofishing.

ODFW biologist Shannon Richardson said that electrofishing is a common tool they utilize to catch and release fish and monitor data.

“We’re really interested in seeing what the species composition is and tracking the various fish populations,” she said on the aim of their latest efforts.

The McKenzie is home to a very diverse ecosystem, and though most famous for its Rainbow trout, other species - Chinook salmon, Steelhead, Cutthroat, Whitefish and Lamprey - inhabit the region.

Electrofishing is a technique that has been around since the 1950s, first used on backpacks with individual biologists and later expanded to use on boats.

Onboard, the two netters control the flow of an electrical current with a foot pedal that is sent to the anodes and cathodes in the water, which stuns fish in the surrounding areas.

They then float to the surface and are scooped up and into the boat for monitoring and are returned to the water.

Altogether it’s a harmless process when the charges are dispersed properly.

March 13 marked the first sampling period of the season.

The McKenzie was sampled periodically in the past to monitor populations, but now it is being analyzed in hopes of comparing results that were found in the 1090s to see if anything is out of the ordinary.

This was prompted after a local called in claiming that he was noticing some changes in the river.

“With just two little snapshots in time it’s not reasonable to say, ‘Whoa, I’m seeing some differences, something must have changed.’ If we’re seeing differences that will lead us to whether or not we need to do more sampling out there,” said Richardson.

Another past program the ODFW led was trout tracking, which was a similar process except instead of just measuring and tracking the results by hand, they inserted radio tags into the trout and could locate where they were on the river at all times.

They even named all 20 of the fish and put the results on a website in which anyone could track all the routes the fish swam on an interactive a map of the river.

“We learned a lot from that process and it didn’t answer all of the questions we had, which is pretty typical of a sampling question, but we learned a lot of questions we could have been asking, and it was a really fascinating study,” Richardson said. 

Richardson said the McKenzie is home to an extremely healthy and vibrant ecosystem, with a wide array of native fish and wildlife.

“What’s really awesome and important about the McKenzie is that many of the tributaries have a great in tact native fish assemblage. You have species that have evolved together and fulfill different niches in the river system. You can really see the multi-tiered benefits of having an intact ecosystem.”