Some king salmon reared in Southeast Alaska are traveling farther north as ocean temperatures rise.
This news was delivered to the Alaska Board of Fisheries as their spring meeting opened in Sitka Monday afternoon.
The three-year meeting cycle of the Board of Fish is designed to take the board to different regions of the state, and a substantial portion of each ten-day meeting is devoted to education — of the board. Regional managers and biologists from the Department of Fish & Game deliver literally reams of data about salmon harvest levels, escapement, and economics.
Most of this information rolls in and out with the tide, and generates little comment from the board. But this fact caught their attention: The king salmon hatched in Southeast’s four top-producing river systems, the Alsek, Situk, Taku, and Stikine, are going very far afield.
This is ADF&G Sportfish coordinator Ed Jones.
“All four of these stocks are considered outside-rearing, or what we term the far-north migrators. This means that shortly after the juveniles enter the marine environment to rear, they essentially take a right and head out to the Gulf of Alaska and Bering Sea.”
Again, these rivers are the four largest producers of king salmon in Southeast. Board member Orville Huntington wanted to know more.
“Do you guys know where it is they’re going?”
Huntington wanted to know if the Department used any sort of telemetry to track the fish.
It turns out telemetry isn’t needed. Jones knows exactly where the kings are going. The National Marine Fisheries Service has increased trawl surveys in the Western Gulf in recent years. The surveys are catching king salmon, some of which have tiny coded-wire tags embedded in their skulls. Those salmon were tagged in Southeast, says Jones.
“They’re typically found from Kodiak west, and what’s interesting to me is that in years of really warm water — which took place in 2005 – 2006 — most of our coded-wire tags were found in the Bering Sea. So that told me that the fish are being opportunistic, and moving with water temperatures. They’re going out to that part of the world, and moving as water temperatures dictate.”
Board member Sue Jeffrey asked Jones to elaborate on this idea.
Jeffrey – You’re saying that warm waters create different patterns. Are they moving to cooler waters then?
Jones – In 2005 – 2006, those very warm water years, they found a Taku coded-wire tag all the way up by St. Matthew Island, which is quite a bit north of the Bering Sea. So that’s what is going on: They have a preferred temperature that their feed is in, that they like to operate in, and they’re moving with it.
Although the Taku, Alsek, Situk, and Stikine produce most of Southeast’s king salmon, Jones said that there are seven smaller stocks that the department considers “inside rearing.” Once these fish enter the marine environment as juveniles, Jones said they remain in regional waters until maturity.