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Dam project funds new fish weirs to study Susitna salmon

  • Author: Jerzy Shedlock
  • Updated: September 27, 2016
  • Published June 17, 2013

The Alaska Department of Fish and Game plans to place five fish weirs on tributaries of the Susitna River in the coming weeks, in order to determine a more accurate census of two salmon species on the heavily-fished river system. Funding for the study comes from the state agency seeking to build what would be the second-tallest dam in the U.S., a project that concerns conservationists as well as energy experts backing an array of other energy megaprojects.

The fish studies related to the weirs are part of the Alaska Energy Authority's five-year study plan, which will look at everything from geology and soils to wildlife, fish and aquatic resources. If all the pieces fall into place, construction on the $5.2-billion hydroelectric project will begin in 2017 and take seven years to complete, according to AEA's schedule.

For now, copious studies are being conducted. Fish and Game will tag and count fish over summer 2013. The study will focus on two species, king salmon, or Chinooks, and silvers, or Coho, on the Susitna, a 300-mile long river in Southcentral Alaska, and its tributaries. Rivers of the Susitna drainage have recently been subject to various fishing closures because of inadequate salmon returns.

Fish and Game workers will operate weirs on the Deshka River -- a site that has been operated by Fish and Game for years -- and on Willow Creek and the Middle Chulitna River, as well as Talachulitna River and Lake Creek in the Yentna drainage. Study designers chose the sites based on annual aerial survey data and the ability to weir the sites, according to AEA's study plan.

Seeking to obtain a thorough survey of kings and silvers for the entire Susitna River, Fish and Game will work through the summer calculating the distribution and abundance of fish. AEA has repeatedly said it understands the importance of protecting the area's aquatic resources. If built, the dam will affect flow, water depth and sediment in the main channel of the as well as at tributary confluences, side channels and sloughs, both upstream and downstream.

The studies will cover the area above the proposed dam site all the way to the Susitna's mouth in the Upper Cook Inlet, said AEA spokesperson Emily Ford.

Late spring no help

Despite the commitment to better understanding the river's aquatic life, Southcentral residents, including local fishermen, have been vocal about the dam's possible detrimental effects to salmon populations, which are economically significant and already the subject of worry.

In the meantime, the studies are moving forward, but the late spring breakup this season put the placement of the weirs behind schedule. So far, a rail, a large piece of iron that holds the weir in place, has been laid down in Willow Creek. The entire weir should be constructed by Monday, said Jack Erickson, Fish and Game regional research coordinator.

The weir at Deshka has been up since June 7. The first fish passed though it two days later.

At the remaining three locations, Fish and Game is busy setting up camp in preparation of more weir construction. The tributaries' waters have stayed high -- too high to place the weirs. Even rain can halt the process. The other locations appear ready, but Lake Creek's flows still are far too high, so workers are waiting to assess feasibility, as the channel has changed at the mouth of the Yentna.

An adaptive resolution imaging sonar (ARIS) was place at the Talachulitna, and Fish and Game plans to place another at the Middle Chulitna. Fish and Game only has these two sonars available for the study, but Erickson said weirs are preferred. The sonars are used when waters are high, he said.

Radio-tag ’em, don’t bag ’em

Placed in two spots along the Susitna are fishwheels, used in years past for other salmon studies. Those spots are where a portion of kings and silvers will be radio tagged. Upstream, Fish and Game workers at the weirs will recapture the salmon -- radio towers along the way and counters at the weir will simply count the total of passing fish that make it to the five sites and use the data to estimate the salmon species in the whole system.

The studies keep piling up, as a 2012 study focusing on kings and pink salmon largely shaped the scope of the current study. The previous study states pinks are found from Devil's Canyon, near the proposed dam site, to the mouth of the Susitna, and in most accessible tributaries. Kings have been observed from the mouth to at least the Oshetna River, and very few of the coveted salmon species has been spotted above the canyon.

In 2012, Fish and Game recorded distribution. This year, and next, the agency will be tracking "where and how many (kings and silvers) are in the entire system," Erickson said.

"It's a difficult thing to do correctly," he said. "We'll get a census, but we won't be able to develop an escapement goal. This study fulfills the project's goals."

AEA says it wants to "focus on describing the current fish assemblage including spatial and temporal distribution, and relative abundance by species and life stage in the Susitna River downstream of the proposed (dam) with an emphasis on early life history of salmonids" and the seasonal movement of the selected species.

How the studies findings will be used remains up in the air. AEA said it will continue to work with state and federal agencies to ensure salmon and fish habitat are "adequately protected." It does not go as far as stating it would halt the project due to serious, negative findings. The Legislature handed over $95.2 million for the 2013 and 2014 studies.

A natural tipping point

Many fishing businesses in the Mat-Su and beyond to Talkeetna, a hamlet near Denali National Park also known as the staging point for summer climbs up Mt. McKinley, rely on the Susitna to make a living. The river's king stock in the fourth largest in the state, according to studies conducted in the 1980s.

Fish and Game says that ranking is a long-standing opinion, though it recognizes the river's importance. Currently, a handful of Susitna's tributaries, including the Deshka, have escapement goals for kings.

The Deshka's escapement goal is 13,000 – 28,000 king salmon. In 2012, it passed the goal by about 1,100 fish.

In 2011, 12 of 17 Upper Cook Inlet streams failed to achieve their escapement goals for kings. Seven of those are the Susitna River tributary streams: Chunilna Creek, Goose Creek, Montana Creek, Prairie Creek, Sheep Creek, Willow Creek and Alexander Creek. For the past two years, there have been sport and commercial fishing restrictions for the 12 tributaries due to the continuing concerns.

Opponents of the dam, like the Coalition for Susitna Dam Alternatives, argue the dam is already at a natural tipping point for salmon.

In the summer of 2008 and 2009, Cook Inletkeeper, a nonprofit advocacy group that aims to protect the Cook Inlet's watershed, conducted testing on the river and concluded 13 of Susitna's tributaries had temperature criteria that exceeded state standards for spawning. The waterways included Willow Creek and the east fork of Chulitna River.

Also in 2008, the Alaska Board of Fisheries designated the main channel's sockeye salmon stock a yield of concern, which is an inability to maintain expected yields, or harvestable surpluses, despite the use of special management measures. Fish and Game recommended that designation continue in February 2011.

That same year, the Board of Fish gave Willow Creek and Goose Creek kings the designation, as well.

AEA will hold an update meeting on its fish and aquatic resources on June 24 in Anchorage.

Contact Jerzy Shedlock at jerzy(at)

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