Harvesters, processors help state track Chinooks

CRPWSMA, CDFU, five processors gift state ARIS sonar

Fishery biologist Shane Shepherd and fishery technician Marie Schmidt deploying sonar equipment below the Million Dollar Bridge. Photo by Iris Fletcher

This year’s Copper River king salmon run has been a glimmer of hope in an otherwise dire looking Copper River flats season. With 7,240 kings caught in the first three fishing periods on the flats, hopes are high for a good king year.

“Last year we saw a little turnaround in the Copper River chinook run and this year, it’s looking good so far, so we’re pretty optimistic,” says Jeremy Botz, gillnet area management biologist for the Alaska Department of Fish and Game.

Kings were once the bread and butter of many Copper River fishermen who targeted them in narrow sand channels inside the barrier islands of the Copper River delta. However, ADF&G has put this prime king salmon fishing territory off limits to the commercial fishing fleet for the bulk of the last 10 seasons because of a mysterious 30 percent decline in king salmon returns to the Copper River beginning around 2008. Last year turned out to be the first historically average sized king run since then.

Sonar research coordinator Suzanne Maxwell guides fishery technicians Iris Fletcher and Aeson Sweat in the deployment of sonar at Miles Lake below the Million Dollar Bridge.
Photo by Shane Shepherd

“Our [king] runs are down across the state, and across their [west coast] range,” said Bert Lewis, central regional supervisor for commercial fisheries at ADF&G. Because the decline in king runs is almost universal, including in areas that are only lightly fished, Lewis believes that ocean conditions are to blame. When they leave as smolt, that first year is probably when we see, we hypothesize, that’s when the majority of the mortality occurs.”

In a recently published article, Lewis and his colleagues have shown that across the west coast, and especially in Alaska, kings are also getting smaller on average and returning to spawn at a younger age. Researchers can only speculate over what changes in the ocean are hurting the kings.

Fishery technician Jon Syder works on sonar equipment at the Miles Lake field station.
Photo by Shane Shepherd

The many theories include a shift in food availability due to warmer water temperatures, competition with a record high number of hatchery pink and chum salmon, as well as a steadily increasing West Coast killer whale population that can eat about the same amount of kings in one year as the entire commercial king harvest coast wide. For each theory, however, there is evidence and counter evidence.

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“It’s a black hole that people have been investigating at many different levels for a couple decades and it’s really hard to tease anything out,” Lewis says.

With all the uncertainty in king enumeration and conservative king salmon management strategies, the fishing industry and the state of Alaska are working together to improve the data on king runs. The ADF&G sonar station at Miles Lake provides invaluable information on the strength of salmon runs on the Copper River, but up until recently could not tell the difference between passing sockeyes and chinooks. Last year, ADF&G installed the first Adaptive Resolution Imaging Sonars (ARIS) sonars at Miles Lake. The ARIS sonars have a higher resolution, and therefore allow scientists to zoom in far enough on the images to actually measure fish.

Images of salmon passing the sonar appear on the computer screen at the Miles Lake field station.
Photo by Iris Fletcher

“What we’ve seen so far in our pilot study is that we can definitely measure fish,” says Jeremy Botz.

Four sonars are needed to accurately count kings at Miles Lake and when the state could only come up with the funding to deploy three of the $110,000 units for the 2018 field season, the Copper River/Prince William Sound Marketing Association, Cordova District Fishermen United, and five processors contributed the remaining funds to purchase a fourth sonar.

“This year we made the decision to help [ADF&G] purchase a tool that will allow them to manage the fishery better”, says Dennis Zadra, Copper River fisherman and treasurer of CR/PWSMA. “We believe that in the future this management tool will more effectively account for chinook within the Copper River.”

“I think it’s going to be excellent for us. Information is good,” says Dave Glasen, Copper River fisherman and lifelong Cordova resident. “I could totally see us getting in season information that could knock us down to maybe five inside closures.”

During the large sockeye runs of 2012 to 2015, the inside of the Copper River flats was closed for up to 10 fishing periods, and each of those years several hundred thousand more sockeye went upriver than the upper escapement goal set by ADF&G, causing potential harm to spawning lakes. Since 2016 the sockeye runs on the Copper River have been smaller than average.

“What this tells me is that they hurt Klutina Lake,” Glasen says. “It’s imperative that we have in season information to change things.”

Marc Carrel is a commercial fisherman, substitute teacher and resident of Cordova.

The south bank sonar site below the Million Dollar Bridge at Miles Lake.
Photo by Iris Fletcher
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