This year, the Chilkat River king salmon run met the 1,750 to 3,500-fish escapement goal for the second year in a row.
It’s likely that more than 3,000 mature kings reached Chilkat River spawning grounds this year, the highest number since 2009, Alaska Department of Fish and Game biologist Brian Elliott said. The 2020 mark-and-recapture study, used to estimate run size, was completed last week, and the results are still being finalized.
Escapement goals are based on the number of mature salmon that need to make it to spawning grounds each year to ensure the population remains sustainable and to maximize the number of smolt that survive—too few fish and not enough smolt will be produced, too many and the smolt survival rate goes down due to competition for limited resources.
Chilkat River king salmon, also known as Chinooks, was designated a stock of concern in 2018 after multiple years of coming in below escapement goals. The past few years, the department has had conservative management restrictions in place to help the population rebound. Restrictions on the commercial drift gillnet fishery have included time and area limits as well as mesh size restrictions.
Last year, the Chilkat River king escapement goal was reached for the first time since 2015, with a return of 2,028 fish.
Elliott said the strong performance in the 2019 and 2020 runs has a lot to do with strong runs in parent years. Most of this year’s fish were five years old, produced during the 2015 run.
“The offspring produced from 2015 spawners were abundant and seemed to survive well. That was a major driver behind this year’s run,” Elliott said.
Another factor that influences run size is the ocean survival rate—a comparison between the number of smolt that leave the river and the number that return roughly three to four years later. The Southeast region has experienced below average ocean survival for Chinook in recent years.
Historically, only about 2.6% of Chinook salmon survive the marine environment on average, so small fluctuations in the survival rate can have a big impact on the local population, Elliott said in an interview with the CVN this spring.
Despite strong runs this year and last year, conservative management restrictions are likely to remain in place in 2021.
“I wouldn’t say we’re out of the woods in terms of consistently meeting escapement,” Elliott said. “The management restrictions in place I think will probably continue. I don’t think we’re in a position to say, ‘We’ve had two good runs, let’s lift them.’”
Runs in the next few years will likely be lower than this year’s run, Elliott said. Based on recent trends, the majority of fish in the 2021 run will likely be five years old, spawned during the 2016 run. The runs in 2016, 2017 and 2018 all failed to meet escapement goals.
“The main goal is to get this stock back on its feet, to the point where we can allow the harvest of excess fish for escapement,” Elliott said. Management restrictions will likely remain in place until the department starts seeing Chilkat kings consistently meeting escapement goals.
Elliott said he expects the department will have final results from this year’s mark-and-recapture study, including a breakdown of fish ages, toward the end of October. At that point, the department will begin work on a run forecast for 2021.