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The salmon yo-yo

 

Alaska Department of Fish and Game harvest data

Once more the pendulum of ocean productivity has swung back to bless Alaska commercial salmon fishermen and processors – or at least some of them – with another season of bounty, according to the season-ending report from the Alaska Department of Fish and Game.

The pattern of massive returns in odd-numbered years and returns only about half that size in even-numbered years is now well established, and 2021 is an odd-numbered year.

Thank the “humpy” as Alaskans commonly call pink salmon, the smallest of the species. About 161 million of them swarmed the 49th state this year.

They drove a total harvest of more than 200 million fish – the sort of catch unprecedented in Alaska history prior to 1995. The 200 million bar has now, however,  been reached seven times in the new millennium.

While the 2000s have marked an era of struggle for the salmon stocks of Canada and the Pacific Northwest, there has largely been only bounty to the north in Alaska.

Even the 2020 Alaska catch of a seemingly meager 117 million salmon, at least compared to the nearly 234 million in total reported caught this year, was well above the size of average harvests in the Alaska territory.

Territorial harvests peaked at close to 95 million per year in the decade of the 1940s before beginning a long decline. By the 1970s, the average annual harvest was down to 49 million.

Ocean cooling

Cold ocean waters and primitive salmon management have been implicated in that decline with the former possibly being far more important than the latter, although state fisheries managers in the 1980s became world leaders in optimizing salmon escapements to boost salmon returns.

Escapement is a fancy term for salmon escaping commercial fishing nets to make it back into the rivers and streams where they spawn. In general since the 1970s, Alaska salmon returns have crept upward as escapement goals have been pushed higher.

Putting more spawners in Alaska rivers and streams is, however, of no benefit if the ocean pastures won’t support the young fish produced by those spawners, and thus the oscillating returns of the past decade have become an interesting issue for scientists.

The big catch-small catch phenomenon of odd years and even years is driven by pinks, both the smallest and fastest-growing of the species.

Since 2011, according to Fish and Game data, the odd-year catch of pinks has averaged almost 159 million fish per year – well in excess of the historic annual average harvests of all species of Alaska salmon dating back to the start of the Alaska commercial salmon industry in the late 1800s.

The even-year catch, meanwhile, stands at an average of about 70 million or about 44 percent of the odd-year harvest.

A significant number of the pinks in both even and odd years are produced by state-supported, commercial-fishermen-run hatcheries that farm the ocean.

The ‘ranchers’

The state has yet to report how many of the pinks in the 2021 catch were farmed or “ranched” as Alaskans prefer to call them, but Fish and Game bragged about hatchery success after the big 2019 harvest of pinks.

“In 2019, the commercial fleet caught about 50 million hatchery-produced salmon worth an estimated $118 million
dollars in ex-vessel value,” the Alaska Salmon Fisheries Enhancement Annual Report 2019 said. “Hatchery fish contributed 25 percent of the statewide commercial salmon harvest and 18 percent of the statewide commercial harvest ex-vessel value.”

The ecosystem implications of artificially boosting salmon returns in this way were not mentioned, though there are those now beginning to question whether Alaska’s hatchery production of pinks and overall management of wild pinks for maximum returns is driving the oscillations in annual returns and possibly depressing salmon returns in Canada and the Pacific Northwest although not all scientists see it this way.

With salmon runs faltering all across Western Canada, Canadians eyeing Alaska’s hatchery success to the north are now, in fact, talking about their own massive hatchery build-out.

The Canadian Department of Fisheries and Oceans (DFO) earlier this year announced a $647 million plan to “support both conservation and harvesting objectives,” the Winnepeg, Manitoba-based Aboriginal Peoples Television Network (APTN) reported in June. 

Whether more hatcheries will help or hurt Canadian salmon has since then become the subject of some debate in that country.

“Climate change has reduced the quality and quantity of the food for fish in the open ocean,” Aaron Hills, executive director of Watershed Watch Salmon Society, told The Narwhal last week. “So the idea of releasing more hatchery fish is like letting more cattle out into a field with less grass and thinking you’re going to get more and fatter cows.”

The Society is a British Columbia-based non-governmental organization (NGO) dedicated to protecting and restoring salmon. The evidence would indicate Hill is wrong in general about the quantity and quality of food in a warmer ocean.

Salmon abundance was at an all-time high in North Pacific in 2018 and though numbers slumped last year, the indications are that they boomed again this year. Alaska’s harvest actually exceeded the projections of state biologists.

But warmer waters or over-grazed pastures or some combination of the two has not been equally good for all salmon. As pinks have boomed, other species of salmon have slumped both Outside and in Alaska.

Alaska Chinook, sockeye and coho salmon have been shrinking in size for decades, apparently due to declining food supplies.

Chinook, the big kings for which the Kenai River was once famous; sockeye, the economic mainstay of commercial fishermen in the Cook Inlet that laps at the doorstep of the state’s largest city; and coho, the famously hard-fighting salmon more often known to Alaskans as “silvers” are the most valuable of the state’s fish – worth four, five and sometimes 10 times per pound more than pinks.

Intriguingly,” researchers wrote in a peer-reviewed published Nature Communications last year, “the shared acceleration of size declines (in these fish) post-2000 occurred during a period of unusually high (though variable) pink salmon abundance in Alaska, suggesting high pink salmon abundances could be accelerating or exacerbating size declines. Our results provide further evidence that wild and hatchery-enhanced pink salmon abundance in the North Pacific has reached such high levels that they appear to be exerting an influence on ecosystem structure and function.”

The oscillations in overall harvest numbers have been linked in theory to the odd-year abundance of pinks.

Barren pastures

The theory, which is widely debated, is that the production of pink salmon in odd-numbered years is so high, leading to the consumption of so much food, that not only do the salmon that spend years at sea suffer but the pink salmon of the following year suffer.

Pinks are on a two-year cycle of spawning, birth, growth and return. Other salmon spend three, four and sometimes as many as seven years at sea.

Advocates for hatcheries contend the North Pacific is so big and the number of salmon so comparatively small that fish overgrazing their pasture is unlikely, and they dismiss the theory that massive numbers of pink salmon could cause what has been termed a “trophic cascade” that affects not only other salmon but birds, other fishes and marine mammals in the North Pacific.

“Correlation is not causation,” as hatchery advocate and state fisheries research director Bill Templeton likes to point out.

David Welch, a Canadian researcher and the lead author on a peer-reviewed paper showing significant declines in ocean productivity for king salmon from Alaska’s Icy Strait south along the Gulf Coast all the way to Oregon in recent years takes issue with that position.

He points to a 2018 study authored by Sonia Batten, Greg Ruggerone and Ivonne Ortiz “showing that the abundance of diatoms and copepods in the Aleutian/Southern Bering Sea region varied in and out of phase with the pink salmon numbers.

“Their observations fit with standard predator-prey theory because the pinks (presumably) graze down the number of copepods in years when they are abundant, allowing the diatoms (copepod prey) to increase in abundance,” he emailed. “Sort of like the wolves eat cows, cows eat grass scenario.

“When wolves are abundant, the grass grows longer.  (And the same story is being told for Yellowstone now, after wolves were reintroduced there and started eating those pesky elk).

“In Sonia’s case study, the pieces certainly fit together nicely and it should counteract the view of a number of my colleagues who ascribe to the view that if you divide the area of the North Pacific occupied by the salmon by the number of salmon you get an extremely large acreage available to each individual salmon, so overgrazing the commons isn’t likely.”

Ocean research driven by noted Canadian salmon biologist Dick Beamish is now also throwing cold water on that idea. Scientists from Canada, Russia and the Lower 48 involved in sampling the waters of the southern Gulf of Alaska are finding that in the sea as on land, there are good habitats and bad habitats for wildlife or, in this case, fish.

Welch admitted, however, that this barren-pasture theory as to how this ecosystem is now functioning is driven by correlations with no causes proven, only adding that he finds “it remarkable how people who make this astute observation have no problem accepting data that fits with their pre-existing beliefs.”

Welch, like Ruggerone, Batten and a growing collection of scientists in the Lower 48 find merit in the overgrazing theory. There are likewise believers in Alaska, but few connected with state management of commercial fisheries willing to publicly say so.

Fisheries management in Alaska is sometimes as much an issue of politics and economics as of biology, and there things get tricky as Welch concedes.

“So overgrazing appears to be a practical reality, and there is empirical evidence for it,” he said. “What isn’t clear is whether this overgrazing (the carrying capacity problem) is severe enough to be counterproductive and actually reduce economic value.

“And then there is that tricky political problem that I may reduce your income while boosting mine – the Alaska versus British Columbia (BC) and southern U.S. issue.”

Alaskans already catch significant numbers of southbound B.C. and Pacific Northwest salmon that have grown fat grazing in the waters off the Alaska coast, and with Alaska hatcheries producing sizeable profits for commercial fishermen and processors in the 49th state, there’s not much reason for them to care what those hatcheries might be doing to salmon elsewhere.

At the end of the day, the commercial fishing business is, after all, a “business” at the end of the day.

 

 

 

 

 

 

 

 

 

 

 

 

 

4 replies »

  1. Reminds me of the second Red run in 2020. The F&G fish counter was registering a plethora of Reds when there were so many Pinks that it was almost impossible to catch anything else. A person at F&G told me they were “sure” the counter was counting Reds, not Pinks. When I asked how it could differentiate, I waited for an answer. Finally the person said, “You’ve got me” or words to that effect. I left my name and number so she could contact me later. That was over a year ago, I’m still waiting….

  2. Thanks for raising this issue about pink salmon over grazing. Our fisheries managers seem content to say, “I don’t know.” How long will they continue to do nothing and stick their heads in the sand, letting kings and silvers go the way of the east coast salmon?

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