Why are the chum runs so low?
In Western Alaska, chum salmon stocks have sharply declined over the last two years. That’s a problem, because people in the region depend heavily on the fish for food and for work. Scientists are in the early stages of trying to understand the crash.
Bill Alstrom lives in St. Mary’s on the lower Yukon River. It used to be that if he wanted fresh salmon for dinner, he’d throw a net in the river to catch a couple. But with fishing closures this season, he can’t do that anymore.
“It’s hard to comprehend that this is happening in my lifetime. It makes me sad just thinking about it,” said Alstrom.
The State of Alaska has closed fishing for chum to protect the runs. For Yukon River families, chum is particularly important. Chinook salmon have been low for decades, but chum were the fish families could depend on until last year, when the summer chum run dropped below half of its usual numbers. This year the run dropped even further, to record lows.
Biologist Katie Howard with the Alaska Department of Fish and Game said that the chum declines are not just occurring in the Yukon River.
“When we talk to colleagues in the Lower 48 and Canada, Japan, Russia, they are all reporting really poor chum runs. So it's not just a Yukon phenomenon. It's not just an Alaska phenomenon, but pretty much everywhere,” said Howard.
So why are the chum numbers so low? The short answer is no one really knows for sure. There are a lot of theories, which this story will walk through starting with one from the people who subsist off the Yukon River.
Every week during the summer, subsistence users, biologists, and fishery managers gather on a weekly teleconference through the Yukon River Drainage Fisheries Association. They share information and ask each other questions, and the subsistence users bring up one theory for the decline again and again: bycatch.
Bycatch is when ocean fishing vessels targeting one species also incidentally kill other fish. Some see it as a necessary evil, while others are opposed to it completely.
The National Oceanic and Atmospheric Association tracks bycatch. Non-chinook chum salmon bycatch is already bigger than normal this year, and bycatch has been trending upwards since 2012.
NOAA distinguishes between non-chinook and chinook bycatch because Chinook bycatch is heavily regulated. If trawlers catch more chinook than allowed, they have to cut short their fishing season. It incentivizes trawlers to avoid chinook feeding grounds.
Trawlers must also report their non-chinook salmon bycatch, but there are no limitations on these amounts. NOAA estimates that 99.6 percent of its non-chinook salmon bycatch is chum.
So, if chum bycatch is greater than normal this year and trending upwards, would bycatch be a major factor in Western Alaska’s chum decline? Not necessarily, said a NOAA spokesperson, because the fish that are dying on the trawlers are largely not bound for Western Alaska. About 16 percent are from coastal Western Alaska and less than 1 percent are from the upper and middle Yukon.
The rest of the bycatch is mostly hatchery fish: fish that have been hatched in a controlled environment. They’re largely from Japan. Hatchery fish are also cited by some as a possible cause of chum decline. Jack Schultheis is the manager of the only wild salmon processor on the Yukon: Kwik'pak Fisheries LLC in Emmonak.
“I think it’s disrupted something in the foodchain,” Schultheis said.
Kwik’pak is Native-owned by a Community Development Quota (CDQ) group called Yukon Delta Fisheries Development Association that also owns trawlers. NOAA data shows that CDQ trawlers are responsible for less than 10 percent of chum by-catch, and Yukon Delta Fisheries Development Association-owned trawlers are responsible for less than 1 percent of chum bycatch on American vessels.
State biologist Howard doesn’t think hatchery fish are the issue. That’s because hatchery fish populations haven’t changed much in the past 30 years. But Peter Westley, an associate professor of Fisheries at the University of Alaska Fairbanks, thinks hatchery fish could be at least part of the problem.
"These declines in salmon that we're seeing in our local rivers is possibly linked to actually, ironically, too many fish in the ocean," Westley said.
Westley said that’s because since the 1970s, the North Pacific Ocean and the Bering Sea have been full of food for both wild and hatchery chum, and both populations have grown over the decades. But now he suspects that the overcompetition for food has led to the massive decline.
“The reality is, you don't know that you were at a tipping point until it's in the rearview mirror,” Westley said.
Westley said that climate change could be the culprit behind the lack of food in the ocean. He said that crashes in salmon stock will be more likely as the ocean continues to warm. Westley said that this overcompetition affects hatchery and wild fish alike, leading to dwindling numbers for all salmon.
On the Yukon River, subsistence fisherman Alstrom also thinks warming temperatures could be a factor in the crash. In his 70 years in St. Mary’s, he’s seen the changes in the environment firsthand.
“All these trees out there looks like a jungle. There used to be scrubs out there when I was growing up,” said Alstrom.
Alstrom said that the animals in the region are changing too. He never saw moose as a kid, but over his lifetime they started to move in.
Researchers are trying to understand the chum crash. For decades, biologists have mainly been focusing on Chinook salmon, which have a longer history of decline and are more valued by commercial and subsistence fishermen.
NOAA and the Alaska Department of Fish and Game are leading two surveys on the Bering Sea this year to study salmon marine life. State biologist Howard is out on one of those surveys right now. She’d like to see more funding to study chum overwintering habitat in the North Pacific, but said that it’s expensive and dangerous to conduct that research because of turbulent winter seas.
Westley said that the number one question that needs to be answered now is where the chum are dying in their lifecycle. That will help scientists determine what’s killing the fish.
Alstrom said that it will be hard for his community if the salmon don’t return.
“It's just not right when you're living in your region that's supposed to be teeming with salmon, and to go without it. It’s just devastating,” Alstrom said.
Despite the decline, biologists say that chum are not endangered and the subsistence fishing closures are helping the salmon get to their spawning grounds.