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New Study Looks At Juvenile Fish Production

On White Salmon River

Above, U.S. Geological Survey fisheries researchers (l-r) Brad Liedtke, Sam Doak, Jill Hardiman, and Jonathan Schafer work up juvenile fish captured through electrofishing last month on lower Buck Creek. The team measured and weighed each fish, then tagged them for later identification by inserting microchips or through fin-clipping. Below is a map of the study area.

Above, U.S. Geological Survey fisheries researchers (l-r) Brad Liedtke, Sam Doak, Jill Hardiman, and Jonathan Schafer work up juvenile fish captured through electrofishing last month on lower Buck Creek. The team measured and weighed each fish, then tagged them for later identification by inserting microchips or through fin-clipping. Below is a map of the study area.

If you remove it, they will come.

That was the expectation among fish scientists as they contemplated the removal of the Condit Hydroelectric Project from the lower White Salmon River prior to the fall of 2011.

The project and its appurtenances, including the massive concrete Northwestern Dam, were completely demolished in 2012, returning the river to free flowing status for the first time since the early 1900s.

PacifiCorp, owner of the Condit project, opted for dam removal over installation of expensive fish ladders that would have restored fish passage on the White Salmon much earlier than 2011-12, yet preserved hydropower generating capacity and Northwestern Lake for recreation.

Today, in the aftermath of project removal, the White Salmon River is teeming with new life — a fact that is being confirmed by an assortment of fish recolonization studies being done under the auspices of federal, state, and tribal fish researchers.

Once such study is being carried out by U.S. Geological Survey (USGS) scientists based out of the Little White Salmon River National Fish Hatchery in the Columbia River Gorge.

“This study is the first effort to look at juvenile fish production in the White Salmon River since the dam was removed,” said Dr. Pat Connolly, a research fisheries biologist with USGS’s Western Fisheries Research Center.

photo

Map of the study area.

The project is being paid for by the Washington Salmon Recovery Funding Board, in partnership with the non-profit Mid-Columbia Fish Enhancement Group (MCFEG), which secured a $66,500 grant through the salmon recovery grant program. (MCFEG contributed local matching funds of $11,736.)

Study partners are using the grant to monitor salmon species returning to the White Salmon River and its tributaries now that the Condit project is gone. The final settlement agreement with PacifiCorp for the removal of the Condit project did not include a requirement to fund fish monitoring.

“The goal [of the study] is to understand the abundance, distribution, origin, and productivity of returning salmon and steelhead listed as threatened with extinction under the federal Endangered Species Act,” according to a project synopsis on the Salmon Recovery Funding Board’s Web site.

The USGS-led study so far has documented juvenile steelhead, coho salmon, Chinook salmon, and lamprey migrating downstream in the White Salmon River.

In the process, scientists are seeking to answer a few key questions about the fish repopulating local streams:

  • What species are recolonizing the river?

  • Where are the fish originating?

  • How many juvenile fish are being produced?

  • What are the timing and survival of juvenile fish migrating out the Columbia River to the Pacific Ocean?

Margaret Neuman, executive director of MCFEG, said the answers to these questions will ultimately help inform fisheries management on the White Salmon River.

“The Condit dam removal was a $37 million project. To make a small investment to figure out what’s coming back is the common-sense thing to do,” Neuman said.

To learn more about juvenile fish in the lower White Salmon River, USFS scientists operated a rotary screw smolt trap from March through May to sample out-migrating juvenile salmon and steelhead.

That phase of the study has been paired with an assessment of fish species composition and abundance in selected anadromous reaches of the mainstem White Salmon and its tributaries.

In the last week of July, USGS researchers temporarily isolated 200-meter reaches of Buck and Rattlesnake creeks by stretching cloth netting across the top and bottom ends of the work area. The cloth had one-eighth-inch mesh to keep fish from leaving or entering the site during the field team’s sampling process.

Scientists then used backpack electrofishing equipment to stun and catch juvenile fish. A team of three researchers waded upstream in the cool waters of Big Buck Creek: one wore the battery backpack and carried a wand that provided the electroshock. Two other members used fish nets to capture incapacitated fish, which were deposited into a bucket.

Scientists took the fish to a work-up station where they measured and weighed each one, and tagged them for later tracking and identification (larger fish were injected with microchips, smaller fish were fin-clipped).

Several of the species being studied are ESA-listed as threatened, and include lower Columbia Chinook salmon, Mid-Columbia steelhead, lower Columbia coho salmon, Columbia River chum salmon, and bull trout.

“Other entities such as Yakama Nation Fisheries and Washington Department of Fish and Wildlife are tracking the number and spawning location of adult salmon, steelhead, and lamprey, but more needs to be done to understand how fish populations respond to a large dam removal, such as happened here,” said Neuman.

An interagency work group that has been guiding the study process on the White Salmon elected to let the river recolonize through natural selection rather than human intervention.

“Natural fish restoration isn’t always done,” Jezorek said. “Sometimes fish are stocked or there are breeding programs put into place.”

Prior to removal of Northwestern Dam, USGS scientists studied fish populations above the former project site in the White Salmon River as well as in Big Buck and Rattle-snake creeks.

Information gleaned through this new study will be compared to baseline data collected by the USGS before October 2011 to better understand the response of fish populations to dam removal.

“We’re collecting information to inform the [fisheries] management and inform the tribes about if there’s ever going to be potential for harvest here,” said Ian Jezorek, a USGS fisheries biologist leading the field study. “Do we have actual self-sustaining populations, do we have something unique here, or do we have a population that’s supported by strays. What do we actually have going on here, and what do we want? Those are questions outside the purview of the U.S. Geological Survey. That’s up to fisheries managers.”

The results of the current study will be presented in a USGS report that will be peer-reviewed before it’s published some time next year.

Connolly noted, “There were high expectations of a large and positive fish response from the dam’s removal, especially by salmon and steelhead. It is through these kinds of studies that we can assess if the expensive dam removal action results in meeting the expectation. And if not, why not?”

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