Jake Musslewhite, a fisheries biologist with the U.S. Forest Service, searches for a radio tag used in a study tracking adult coho salmon in the Dredge Lakes drainage system. (Michael Penn | Juneau Empire)

Jake Musslewhite, a fisheries biologist with the U.S. Forest Service, searches for a radio tag used in a study tracking adult coho salmon in the Dredge Lakes drainage system. (Michael Penn | Juneau Empire)

The story of five spawning salmon

Fish scientist tracks cohos using radio telemetry

Standing next to “Colossal,” one of the beaver dams in the Dredge Lakes area, it’s not hard to imagine how difficult it is for coho salmon to traverse. The dam barricades off all but a narrow strip of a slough east of Dredge Lake, where water passes over a two-foot-high waterfall.

Dams act as both a positive and negative for coho salmon, which swim through the middle of the beaver habitat to spawn in nearby Powerline Creek, said U.S. Forest Service fisheries biologist Jake Musslewhite. Using radio telemetry, an animal tracking method using radio signals, Musslewhite tracked five spawning salmon this fall. He found obstacles like dams significantly thwarted salmon’s progress to Powerline Creek.

Musslewhite thinks it’s the first radio-telemetry study conducted in the area.

“All these ponds actually make great rearing habitat, so it’s a good place for little baby coho to grow up,” he said. “But you need the adult coho to make those little baby coho in the first place. So they have to get over those beaver dams all the way back up to the base of the mountain there.”

Jake Musslewhite, a fisheries biologist with the U.S. Forest Service, pauses while searching for a radio fish tag in Dredge Lake on Wednesday, Dec. 4, 2019. Musslewhite has been conducting a study tracking adult coho salmon in the Dredge Lakes drainage system. (Michael Penn | Juneau Empire)

Jake Musslewhite, a fisheries biologist with the U.S. Forest Service, pauses while searching for a radio fish tag in Dredge Lake on Wednesday, Dec. 4, 2019. Musslewhite has been conducting a study tracking adult coho salmon in the Dredge Lakes drainage system. (Michael Penn | Juneau Empire)

Musslewhite led the Empire on a hike on Wednesday morning to the dam site, only about a 15-minute walk from the Juneau Ranger District office. Two months earlier, Musslewhite and Juneau-Douglas High School: Yadaat.at Kalé students equipped five cohos with radio tags, which were then used to track the fish using a receiver and antenna.

“Each tag is transmitting on a specific frequency,” Musslewhite said. “So you can set the receiver just to listen on that frequency and using a directional antenna you can establish the direction it is and using the signal strength, or essentially the volume of the beep, you know when you’re getting closer.”

Musslewhite said the fish enter the system via Mendenhall River and Holding Pond, located a short distance from the river. It was in Holding Pond where Musslewhite and the students radio-tagged the cohos in October. Of the five fish tagged, only two made it past one of the dams adjacent to Holding Pond.

“Based on just a handful of fish in this pilot study, it looks like a pretty tough haul for them,” Musslewhite said. “A lot of them couldn’t even really clear the first step, a lot of them met an untimely demise at the hands of otters, and maybe even just one made it all the way to the spawning grounds out of the five I tagged.”

For over a decade, the Beaver Patrol has kept a close eye on the beaver population of Dredge Lakes. The nonprofit conducts various jobs in the area and have an official partnership with the U.S. Forest Service. Mary Willson said the group formed about 12 years ago and works to minimize trail flooding events and keep waterways open for spawning coho and Dolly Varden trout.

“We open up some dams, yes, (but) we seldom to destroy them altogether,” Willson said.

She said the nonprofit group surveys some of the salmon on their own but added Musslewhite’s research could be beneficial.

“What he learns about them getting up is, of course, useful, but it adds to what we also know,” she said.

Musslewhite said he plans to tag more salmon next year and continue to research their migrations.


• Contact sports reporter Nolin Ainsworth at 523-2272 or nainsworth@juneauempire.com.


More in News

A Princess Cruise Line ship is docked in Juneau on Aug. 25, 2021. (Michael Lockett / Juneau Empire File)
Ships in Port for the week of Sept. 25

Here’s what to expect this week.

Police vehicles gather Wednesday evening near Kaxdigoowu Héen Dei, also known as ]]Brotherhood Bridge Trail, while investigating a homicide. (Ben Hohenstatt / Juneau Empire)
Police: Woman was walking dogs when she was killed

JPD said officers are working “around the clock” on the criminal investigation.

In this photo provided by the U.S. Coast Guard, a Coast Guard Cutter Kimball crew-member observes a foreign vessel in the Bering Sea, Monday, Sept. 19, 2022. The U.S. Coast Guard cutter on routine patrol in the Bering Sea came across the guided missile cruiser from the People's Republic of China, officials said Monday, Sept. 26.  (U.S. Coast Guard District 17 via AP)
Patrol spots Chinese, Russian naval ships off Alaska island

This wasn’t the first time Chinese naval ships have sailed near Alaska waters.

An Alaska judge has ruled that a state lawmaker affiliated with the Oath Keepers, Rep. David Eastman, shown in this February 2022 photo, may stay on the general election ballot in November even though he's likely ineligible to hold public office  (Peter Segall / Juneau Empire File)
Judge keeps Oath Keepers lawmaker on November ballot

Judge ordered delaying certifying the result of the race until a trial scheduled for December.

Water rushes down Front Street, just a half block from the Bering Sea, in Nome, Alaska, on Saturday, Sept. 17, 2022 as the remnants of Typhoon Merbok moved into the region. It was a massive storm system — big enough to cover the mainland U.S. from the Pacific Ocean to Nebraska and from Canada to Texas. It influenced weather systems as far away as California, where a rare late-summer storm dropped rain on the northern part of the state, offering a measure of relief to wildfire crews but also complicating fire suppression efforts because of mud and loosened earth. (AP Photo / Peggy Fagerstrom)
Repair work begins in some Alaska towns slammed by storm

ANCHORAGE — There’s been significant damage to some roads and homes in… Continue reading

j
Sniffen indicted on sexual abuse counts

Sniffen will be arraigned Monday.

In this undated file photo the Trans-Alaska pipeline and pump station north of Fairbanks, Alaska is shown. (AP Photo / Al Grillo)
Oil price drop endangers plan to fund Alaska schools a year early

If oil prices fall, amount is automatically reduced to an amount the state can afford. At

(Michael Penn / Juneau Empire File)
Juneau Police Department announces technology and reporting updates

Emergeny services and direct reporting will not be interrupted

The hoverfly can perceive electrical fields around the edges of the petals, the big white stigma, and the stamens. (Courtesy Photo / Bob Armstrong)
On the Trails: Electric flowers and platform plants

You cannot see it, it’s electric.

Most Read