The Alaska Department of Fish and Game is predicting another strong run of sockeye salmon to Upper Cook Inlet next season, on the heels of two above-average years.
The forecast is for a return of 6.7 million sockeye to all river systems and a harvest by all user groups of 4.9 million sockeye, 1.1 million fish above the UCI 20-year average of a 3.8 million sockeye harvest.
The 2012 harvest was 4.4 million sockeye by all user groups.
The Kenai River return drives most of the fishery, and the 2013 forecast includes a year class that historically has not had significant numbers, but has given the runs a substantial bump in the last couple of years, according to area management biologist Pat Shields.
Shields explained that age 2-3 sockeye, which spend two years in fresh water and three years in the ocean, have been coming back to the Kenai River in record numbers, and in 2013 are forecasted to return at a rate 194 percent above the 20-year average for this year class.
Most fry only spend one year in fresh water, and two to three years in salt water.
“They’re really not any bigger when they come back,” he said, “but when you have more of them in the return, the average size of the return will be a little larger.”
Fishery managers first started noticing the large numbers of age 2-3 fish during a surprisingly strong Kenai River sockeye return in 2011, when they had been expecting around 275,000 of that year class to return, and instead 2.9 million came back.
Still, they were cautious in their forecast of the return of the age 2-3’s for the 2012 season, because it was a relatively new phenomenon.
Their confidence in the 2013 forecast is somewhat more solid because of the experience in the two prior years.
“The confidence has gotten a little better because when you continue to see them come back, you can relate that to other parameters,” Shields said.
Shields said that the Alaska Department of Fish and Game makes an annual trek to Kenai and Skilak Lakes to count the fry, and their trip in 2008 to count the fry from 2007, as with the two previous falls, showed an unusual amount of fry that had stayed in the lakes an extra year.
The department also keeps track of the out-migration of smolt from the lakes, headed for salt water, which also showed a larger number of fish that had stayed in the lakes for two years.
“So our fall fry and our smolt program are indicating to us that we will have a larger than average return of (age 2-3’s) next year,” Shields said.
The atypical number of age 2-3’s is largely the result of over-escapement in the Kenai River, according to Shields.
He said normally they see about 90 percent or more of the fry in the Kenai and Skilak Lake systems smolt out in the first year. However, in the past few years there has been a much larger average, as much as twice the average, staying over until age two.
“One of the reasons that can occur is competition for resources,” Shields explained. “They didn’t get large enough at age one to smolt, and so they had to hold over an additional year, putting on body fat, to smolt out. We have seen that in the past when we’ve had large escapements.”
Shields said that there is some mortality associated with staying in the lake an extra year, especially with repeated large escapements, because of the competition for food.
“If you have a bunch of the age ones stay an additional year, and then you have the next year’s fry of a big escapement, and they come out into the lake and they’re looking for food to eat, then they’re now competing with the hold-overs from the previous year,” he said.
Shields said that as escapements come down, fry should start to revert to normal behavior and head to salt water after their first year.
As for people who use the recent robust runs to say that there is no such thing as over-escapement, Shields said that they are misguided, but that no one at ADF&G is predicting an extinction of the Kenai sockeye run as a result of too many fish in the system.
“The department has never said that over-escapement will cause a stock to go extinct,” he said.
However, he did say that large escapements produce reduced yields per spawner on average.
Shields said there was plenty of data from both under- and over-escaped years, and that years when escapement goals were met but not exceeded, average yields were almost twice as high as on years with large over-escapement.
He said there were anomalies in the data, but when averaged out, years that do not see over-escapement have much higher yields.
“We are supposed to manage our fisheries, when possible, to maximize yields,” he said.
Shields said that the Kenai River king salmon returns again may prove problematic for managers, who were forced to shut down almost the entire east side setnet fishery in 2012 due to low returns, especially in light of the fact that a large number of kings came back to the Kenai River in August, after the sockeye fishery had closed for the year.
He said that usually 10 to 15 percent of the king run comes back to the Kenai River in August; however, last year was probably twice that number.
The final numbers are still being tallied, but he expected it to possibly be more than 30 percent, perhaps as high as 40 percent that came in late, meaning there were undoubtedly more setnet closures than necessary.
“Those are nightmares for managers,” he said. “It wouldn’t surprise me when the numbers are all tallied if it was the latest (king) run ever measured.”
Shields said that that may change management for next year.
“We’ll be cognizant, obviously, of what happen in 2012.”
Cristy Fry has commercial fished in Homer since 1978. She also designs and builds gear for the industry. She
currently longlines for halibut and gillnets salmon in upper Cook Inlet aboard the F/V Realist.