Chinook salmon returning to Chilkat River spawning grounds this year failed to meet the state’s targets, troubling Alaska Department of Fish and Game experts with the lowest estimated numbers since 1991.
Preliminary fish and game department surveys estimated only 1,373 large fish returned to Chilkat River spawning grounds in 2016, which was well below—even factoring in margins of error—the minimum goal of 1,750 spawning fish.
Even state fishing limits enacted earlier this year were unable to boost chinook numbers to a healthy level. Sport fishers in the Lynn Canal were limited to one chinook of 28 inches or more between April 15 and Dec. 31, and Chilkat Inlet was closed to chinook fishing from April 15 to July 15.
The state also closed Chilkat Inlet to chinook fishing last year, with apparent success. This year, however, it appears the move was not enough.
“They didn’t show up in our fisheries. They didn’t show up in our rivers. They didn’t show up, period,” said Brian Elliott, chinook salmon stock assessment biologist in the Haines office for the Alaska Department of Fish and Game.
To estimate the numbers of returning chinook, an indicator of the strength of the season’s run, the state uses a mark-recapture system. The system is a two-step process involving tagging young fish as they head to the ocean and then sampling upstream areas when the adult fish returned in August and September.
Philip Richards, a Juneau-based chinook research supervisor for the Southeast Alaska Region, said the king salmon numbers were among the lowest he’d seen.
“Region-wide, the escapements in 2016 were on par with the lowest escapements we’ve measured in 40 years,” Richards said.
“It was unexpected,” he said. “We were expecting returns to tick up again this year.”
Low projections this year caused the second consecutive cancellation of the Haines Sportsman’s Association’s King Salmon Derby, a fundraiser for scholarships and youth activities.
“We decided it was in the best interest of the fish not to do it,” said Charlie DeWitt, the association’s president, in March. “There’s no fish and it wouldn’t be profitable for us.”
Haines was not alone in its low king numbers. All but two of the 11 chinook salmon index systems monitored by the fish and game department in Southeast Alaska failed to reach their escapement goals.
Chinook harvests were also drastically below normal. Preliminary Fish and Game estimates put the Chilkat River king harvest at only 45 fish—a significant new low. From 2006 through 2015, the average annual harvest was 746 salmon, and the previous low was 432.
These numbers, Elliott said, show that the small run this year could not be attributed to overfishing.
“The answer to that is a loud ‘No,’” he said.
The real cause is much more elusive. State researchers are finding normal smolt numbers in the rivers early in the year, suggesting that hatching and survival rates for young fish are good. The problem seems to be that chinook salmon are encountering hostile conditions in the open ocean.
Further evidence of this is data that shows kings returning to the Chilkat River are younger than normal, which could indicate that survival in the ocean is too difficult for the fish to sustain for many years.
Richards, the Juneau-based research supervisor, said the agency was still compiling data to learn more about the 2016 run. One of the big questions the agency hopes to answers is how many generations of salmon were experiencing low populations.
“It looks like it’s multiple generations of chinook salmon returning to Southeast that did extremely poor this year,” Richards said, but added that further data will provide a more definitive answer.
But for now, whatever is decreasing salmon survival in the ocean is unclear.
“There are sources of mortality in our ocean that we cannot identify,” Elliott said.