The shrunken-size Chinook of the modern Copper River/Craig Medred photo

Despite the Alaska Department of Fish and Game’s 2021 forecast of another monster catch of 190 million salmon  – more than twice the state’s average annual harvest in the 20th Century – the news from the Lower 48 is that the most prized fish in the 49th state are in trouble.

“The giant schools of wild Pacific salmon that can turn Southeast Alaska’s ice-cold waters into a brilliant orange blur are thinning out, and those that do survive are shrinking in size,” Bloomberg reported late last month in a story that was picked up by Yahoo and others and spread widely. 

“Poor salmon runs, smaller fish having impact on Alaska’s supply chain,” Seafood Source, a trade publication headlined this week.

Coming on the heels of the Netflix documentary “Seapiracy,” which portrays commercial fishing in general as a dire threat to the world’s oceans, some in the state’s fishing industry are privately fretting about what such reporting could do to markets for commercially caught wild salmon this summer.

“Imagine a world where the oceans have ZERO fish.” the scandal-chasing website TMZ proclaimed when Seapiracy first aired earlier this year. “That’s pretty much doomsday for the planet, and it could happen by 2048 … at least based on (producer) Kip Andersen’s research while making ‘Seaspiracy.'”

Since March, the fishing industry and even the environmental group Oceana have been pushing back against the documentary as inaccurate, but that hasn’t stopped some websites from proclaiming “Seapiracy: The Netflix Documentary That Will Stop You From Eating Fish.”

And this was before the news broke off Alaska salmon runs in trouble.

“Decades after the Atlantic cod fisheries collapsed, concern is now mounting among experts that wild Pacific salmon could face a similar fate,” wrote Kim Chipman at Bloomberg, apparently unaware that cod are a long-lived species subject to constant fishing pressure while salmon are a short-lived species harvested only as they return to the streams of their birth.

This difference alone makes salmon harvests far easier to manage for conservation purposes.

Nuances

One of the scientists quoted in the Chipman story admitted their comments were taken out of context and the many nuances of Alaska salmon management missed, but complimented Chimpan for bringing to the attention of Outside readers the problem of the shrinking size of Chinook, sockeye and coho (silver) salmon in a story that bangs the drum for the mainstream media’s global warming agenda.

The declines in average sizes of longer-lived salmon “almost certainly presage more costly changes to come and, much more importantly, raise alarm bells about the growing crisis in some key salmon populations that is being driven, according to many scientists, by climate change and more competition for food,” according to the story.

There is no doubt about salmon shrinking in size. That has been going on for decades amid a growing debate about the salmon carrying capacity of the North Pacific Ocean with both Alaska and Russia recording unprecedented harvests in size in warmer waters.

Seattle-based research scientist Greg Ruggerone and Canadian colleague James Irvine in 2018 authored what is considered the definitive estimate on Pacific salmon populations at this time; it concluded that salmon are now more abundant than at any time in recorded history.

With more salmon than ever swimming around in the Pacific, it’s hard to say fish are in crisis, but the mix of salmon is shifting and outside of Bristol Bay – where climate warming has benefitted sockeye or what are sometimes called red salmon – the salmon that spend years at sea are generally declining in number as short-lived pink salmon increase.

The smallest of salmon, pinks – or what Alaska’s typically call humpies because of the hump-backed shape of males on the spawning grounds – spend only about 18 months at sea before returning to spawn.

Boosted greatly by Alaska hatchery production, they are projected to account for more than 65 percent of the 49th state harvest this year.

Hatcheries have helped push the Prince William Sound pink salmon harvest from an average of 3 million fish per year from 1971 to 1979 to about 45 million per year for the past several decades.

The Sound harvest hit a peak of 92.6 million in 2013. That was about twice the size of the entire annual harvest of all species of Alaska salmon in the 1970s when total statewide catches averaged 49 million per year.

Regional differences

While the state forecasts another rosy, near-200-million harvest statewide this year, not all areas of the state or species are slated to share in the bounty:

• The 28 million humpy harvest predicted for the Panhandle region is only average.
• Copper River and Sound predictions for sockeye and Chinook harvests are below average with predictions for pinks and chums above average.
• Cook Inlet returns of both sockeye and pink salmon are expected to both be below average with the former well below.
• Kodiak pink returns are expected to be above average with some Kodiak sockeye returns above and some below average.
• Bristol Bay sockeye are expected to be above average.

This sort of variation is an Alaska norm, but there is at least one overriding generality that has shown itself in recent years – Chinook, the big “kings” so prized by Alaska anglers – are struggling almost everywhere.

No one knows why,  but a peer-reviewed study published in Fish and Fisheries late last year documented a big decline in Chinook numbers from Alaska south to the Pacific Northwest over the past 50 years.

The data surprised Canadian David Welch and his associates at Kintama Research Services in Nanaimo, British Columbia who expected Chinook from southern watersheds impacted by logging, agriculture, industry, freeways and big cities to be in far worse shape than those from the wild and undisturbed watersheds of little populated Alaska.

“The historical pattern of declines in salmon abundance (steeper in the south, less so in the north) were originally assumed to reflect a freshwater (human-driven) cause because of the greater degree of freshwater habitat modification in the more populous southern regions,” they wrote.

But that isn’t what the study found. Instead, it documented a nearly 65 percent, coastwide drop in Chinook numbers since an ocean regime change in the late 1970s shifted the waters of the North Pacific from a generally cooler to a generally warmer state.

“The abundance of salmon in the North Pacific has reached record levels,” the Kintama researchers concede. “However, most of the increase is in the two lowest valued species (pinks and chums) in far northern regions, at least in part due to ocean ranching.

“In contrast, essentially all west coast North American Chinook populations including Alaska are now performing poorly with dramatically reduced productivity.”

The Canadians suspect the big, long-lived kings which spend years at sea are losing out in the competition for food on the ocean pastures, but that theory is hard to confirm given that precious little is known about the lives of salmon in the ocean.

Another peer-reviewed study by scientists at the University of Washington theorizes the decline could be due to predation by killer whales.

When those scientists modeled possible reasons for the decline in numbers and size of Chinook, they reported “simulations suggest that the decline in mean size results from the selective removal of large fish and an evolutionary shift toward faster growth and earlier maturation caused by selection. Our conclusion that intensifying predation by fish-eating killer whales contributes to the continuing decline in Chinook salmon body size points to conflicting management and conservation objectives for these two iconic species.”

Scientists in the Lower 48, Canada and Russia are increasingly turning their attention to the ocean to try to sort out survival issues, but Alaska has devoted little attention to the waters where salmon spend most of their lives.