2016 saw a poor run of king salmon in the Chilkat River. The lowest escapement estimate in about 25 years. The trend has persisted in the area over the last 10 years and it’s not expected to let up soon.
“Our escapement estimates—that’s large Chinook returning to the Chilkat River drainage – from ’91 to 2006, we average 4,442 spawners,” says Brian Elliot. He’s a Chinook stock assessment biologist with the Alaska Department of Fish and Game in Haines. He’s also a member of the Pacific Salmon Commission. “From ’07 to now, including 2016, that average is basically halved.”
“Our average for that 10 year period is 2,201,” says Elliot. “So that’s the first real alarming piece of data is we’re not getting the returns back that we had seen historically through the time series.”
This year’s Chinook run was poor. The escapement estimate was 1,368 large Chinook in the drainage. That’s fish older than 5 years. And that is the lowest estimate since 1991. But Elliot says the big concern right now is that’s not an isolated case.
“The primary concerns are that we are in about a ten-year period of poor production,” says Elliot.
Fish and Game has a few different ways of tracking this trend.
“We’re able to estimate the juvenile production, estimate what the catches are on that particular year, and also estimate what ends up in our spawning areas,” says Elliot. “So all of that data combined gives us a full run reconstruction on Chilkat chinook. That really helps us understand what’s going on with the population.”
As to why this is happening – there isn’t one answer. One thing Elliot is seeing is low marine survival. That is, how many smolts survive to be mature adults.
“We actually are having more smolt leaving the drainage recently then before when you had good adult returns,” says Elliot. “Now that might lead you to believe, or lead to the question: what the heck is going on? More smolt are leaving the drainage and more smolt are dying in the marine environment.”
Elliot says they’re seeing a greater than 1 percent decrease in marine survival, which is around 2,000 fewer returning adults.
“So you can see how sensitive our returns are to how well they survive in the ocean,” says Elliot. “If we had an extra 2,000 fish coming back to the Chilkat this year we’d all be doing cartwheels. We would not be in this situation perhaps.”
On top of that, Elliot says fish are returning sooner than normal – that’s called early maturation, and it means the fish that are returning are smaller than they used to be. He says seven-year-olds are rarely seen. And now, fewer six-year-olds are coming back.
“Those are the big productive spawning Chinook that everybody’s used to,” says Elliot. “Well that age class is slowly disappearing throughout the last several years. And that’s a big concern in my mind. If that maturation rate change becomes directional, kind of permanent, they we just have to rethink the way we’re studying these fish.”
One problem with smaller, younger fish returning is that they’re believed to be less-productive spawners. Elliot says it can also be a problem when you start to see less age diversity among returning fish.
“When you have multiple age classes at the same time, the neighboring ones can kind of cover for that,” says Elliot. “Whereas if we become kind of a one trick pony, where we have a single mature age fish in our drainage, then the risk of that single class behaving poorly is much greater and that perpetuates itself through time.”
Elliot says these are problems that are happening around Southeast.
“We have a lot of data to compare and say is this happening on your river, is this happening on the Southern end? Is this a Northern effect? And what we’re seeing is this is a common effect to all Southeast Chinook,” says Elliot.
So, what can be done about it?
“Obviously we can take care of our own back yard,” says Elliot. “We can cut down Chilkat Inlet sport subsistence. That’s something we can do locally – and Lynn Canal for that matter.”
But it’s not limited to one group of users. Elliot says all users share in restrictions. That means subsistence, sport, and commercial.
“We can cut back on some other fisheries that are perhaps high interception fisheries for our Chilkats and other Southeast stocks,” says Elliot. “So that’s all things that managers and researchers this winter are going to sit down and chop it all up, and see what we can do to protect not only the Chilkats but our Southeast wild Chinook stocks in general.”
In recent years, Elliot says area management has been conservative across the board and that is likely continue as the trend is expected to persist into next year.