As wild salmon stocks continue to struggle across Alaska, advances in research are creating a clearer picture of the many factors contributing to lower returns, lowers sizes and lower survivability.
That’s the good news, by the way — that there’s a greater understanding of all the bad news impacting wild salmon stocks.
“If really the question is, ‘Do I think that we’re just sort of in a down cycle? The bright side is coming next year or some year down the road?’ I don’t think so,” said Dr. Peter Westley, associate professor of fisheries with the University of Alaska Fairbanks College of Fisheries and Ocean Sciences.
Westley gave a “State of the Salmon” presentation at Kenai Peninsula College on Thursday night, followed by a panel discussion on the challenges salmon face, the research being done and what could help ensure healthy populations.
King salmon top the list of struggling salmon species across Alaska, with some of the lowest runs on record in the last few years. When the decline in kings became irrefutable about 10 years ago, it led to increased research into what could be going wrong.
Kings are challenged at all stages of the life cycle. In freshwater, kings in the Yukon are increasingly found to have a parasite that attacks cardiac tissue, making it harder to complete their very long journey upstream. Warming waters and heat stress can impact reproductive performance. And warmer waters can increase the activity of predators, like northern pike.
“Pike really like eating juvenile salmon,” Westley said. “What’s going to happen if things continue to warm up? So predators, like all cold-water fishes, as things heat up, their metabolism speeds up. Consumption’s likely going to go up. So how many more salmon potentially are going to get eaten because of climate change?”
Life isn’t easier out in the ocean. Ocean mortality is on the rise. With restrictions on harvesting marine mammals, there are more predators, like seals, sea lions and killer whales, looking to snack on salmon.
“There are likely more predators in the ocean now than there have been likely in thousands of years,” Westley said.
And human harvest takes a toll. One of the questions to the panel was about salmon mortality as bycatch in the trawler industry. Westley says data provided by the trawl industry doesn’t show enough salmon bycatch to make it the smoking gun in declining king stocks.
“The numbers just don’t explain the dramatic decline in abundance,” Westley said. “But it should not be taken as it doesn’t matter. Even if you can’t explain the decline in Yukon chinook, some Yukon chinook are being caught every year. And it’s a fact that some fish are being caught every year by the pollock industry when the local people get none. And that is fundamentally unfair.”
Even with declining king stocks, Westley says about 5 billion salmon are still released into the North Pacific Ocean, both wild and hatchery-produced fish. And they’re all looking for food.
“And there’s increasing evidence that there is competition and limited amount of capacity for feed and growth in the ocean” he said.
It’s not a rosy picture. But in Alaska, at least, it might not be too late.
“The bright thing is that Alaska is still so unique, anywhere in the world, that the connections between salmon and people are still intact,” Westley said. “And they are still intact here in Alaska because, at the core, we still have functioning intact watersheds and habitat that produces salmon.”