Mainstream East Coast media have finally discovered that scientists from around the Pacific Rim are trying to sort out the secret lives of salmon at sea in hopes of unraveling what has been causing wild fluctuations in year-to-year productivity.

And, of course, per their agenda, it’s all about “climate change.”

“Salmon travel deep into the Pacific. As it warms, many ‘don’t come back,”’ headlined the Washington Post.

The ominous headline is strangely enough an understatement. Most – not just many – salmon ‘don’t come back,’ And that is the way it has been ever since scientists began studying the species.

Most ‘don’t come back’ defines the life history of these fish. Average marine survival rates have historically ranged from a low of 1.4 percent for chum to a high of 13.1 percent for sockeye salmon, according to a PowerPoint put together by researchers at the University of Washington using data from the 1960s, ’70s and 80s.

To put these numbers another way, 98.6 percent of the little chum salmon that make it to sea ‘don’t come back.’ The operative number for pinks is 97.2 percent; for Chinook, 96.9 percent; for coho, 89.8 percent, and for sockeye, 86.9 percent.

That’s a whole lot of salmon that have been in don’t-come-back mode for a long, long time, and the weird thing is that Post somehow seemed to miss the most interesting trend among these don’t-come-backers this century.

More come back now than ever before.

All a reporter had to do was look at the chart compiled by the North Pacific Anadromous Fish Commission, a treaty organization comprised of salmon-producing nations, to get a clear view of how much North Pacific salmon production has shot up since the reversal of a coldwater phase of the ocean that persisted from the 1940s into the early 1970s.

Big harvests now

North Pacific Anadromous Fish Commission

As is obvious (see the chart above), salmon harvests varied up and down around 400,000 metric tons in the ’40s, ’50s and ’60s before starting to climb in the late 1970s at the start of a trend that has seen annual harvests sometimes topping 1 million metric tons – two and half times the production of the “good old days” – of the post-war years.

Sadly, the Post reporter was so busy looking at the trees he missed the forest.

Instead of digging down into the possible drivers of today’s wide swings in these annual salmon numbers – some of the year-to-year changes now amount to a half to three-quarters of the entire harvest in those post-war years – the Post just jumped  to the conclusion that “as the planet warms, driven by the burning of fossil fuels, scientists say changes in ocean conditions are helping drive these wild swings and collapses of key stocks.”

Who those scientists might be the story does not say. Among scientists studying the North Pacific, there have been far more discussions of collapses driven by trophic cascades sparked by pink salmon than by warming water.

In the big picture, it’s especially mind-boggling how the Post missed the widely discussed estimate of salmon numbers put together by Pacific Northwest researchers Greg Ruggerone and James Irvine, who in 2018 reported there were more salmon in the Pacific than at any time in recorded history.

It is almost as if the Post, the New York Times, and some other East Coast media are conducting an organized misinformation campaign.

Global warming could one day do in the salmon of the Pacific, but the metabolic theory, which generally holds that warmer oceans are more productive oceans, appears to be holding true to this point as Swiss scientists reported in 2019.

Not that this can be guaranteed to continue forever. Salmon are a cold water species – not a tropical fish – and at some point, warmer water is destined to become more of a liability than an asset. For some species, it is even possible that line is now being approached or might even have been crossed in some southern areas of the salmon’s range.

Losers and winners

Residents of the Pacific Northwest have legitimate reasons to worry about the future of Columbia River Chinook, the salmon some call king. The largest and most famous of the Pacific salmon have been generally shrinking in size and number for decades while pink salmon, the smallest and least valuable of the species,  have been returning from the sea to plug the bays of Alaska’s Prince William Sound, home to the biggest ocean ranching operations in the world.

Sound pinks, many of hatchery origin; wild Bristol Bay sockeye from the big bay at the southern end of the Bering Sea; and the pinks of Russia have been the key drivers in pushing Pacific harvests over that unprecedented mark of `1 million metric tons seven times since the start of the 2000s.

Temperature clearly plays a role in boosting the numbers of salmon in these northern areas. Temperature and precipitation are the two big climate variables that interact with all ecosystems. But global warming might not be the biggest player in the wild oscillations in salmon numbers seen for a decade in the North Pacific now.

As Ruggerone told K.C. Mehaffey of the NW Fish Letter earlier this month, “people
are reading about the heat waves in the ocean. But they don’t recognize the tremendous abundance of pink salmon, and the combined effects of pink salmon abundance and climate change.”

Those pinks – some the result of farming the ocean, some the result of decades of Alaska managing pink fisheries for maximum productivity –  boost salmon numbers sky-high when they aren’t bringing salmon numbers crashing down.

Ruggerone, an independent fisheries consultant – along with Irvine and Brendan Connors with Fisheries and Oceans Canada, and other colleagues – have reported the salmon crash of 2020 was the largest ever recorded. The overall harvest dropped 187 million fish below the 10-year average with chums, down 42 percent and pinks, down 40 percent, leading the way.

“We hypothesize that a tipping point was reached in the North Pacific Ocean, leading to the substantial decline of all five species of Pacific salmon in 2020. We infer that the tipping point was caused by the combined effects of unusually frequent marine heatwaves since 2014 and exceptional back-to-back year abundances of pink salmon in 2018/2019,” the researchers told the NPAFC.

How the heat waves play into the picture is complicated. Warmer water appears to favor pink salmon, the smallest of the six species. It also appears to disfavor Chinook, the largest of the species.

Chinook numbers have gone down as pink numbers have gone up, and salmon production overall has shifted north over the decades with Russian and Alaska harvests of the fish increasing and harvests in Canada and the U.S. Pacific Northwest, and to a lesser extent in Japan, declining.

This is arguably good for Alaska. Pinks aren’t the most valuable salmon in the sea, but there is money to be made off of them. Demand for their roe remains high in Asia, their carcasses can be either stuffed into cans or ground into fish meal, a growing Alaska export.

This is not, however, good for the Pacific Northwest where the important harvests have always revolved around Chinook, sockeye and coho.

There might well be at play here a bit of the so-called “tragedy of the commons,” wherein personal self-interests undermine the common good.

“It is not surprising that fishery managers are primarily concerned with maintaining those
populations that return to regions they manage with little consideration for how these populations might adversely affect other salmon,” as Ruggerone, Irvine and Connors put it in a report to the NPAFC this winter. “Likewise, hatchery managers release large numbers of juvenile salmon to maximize harvests in nearby salmon fisheries, often with little consideration for, or understanding of, potential competition effects on other distant
salmon populations that compete for the same common pool of resources at sea.”

Global warming

Rather than driving this problem, global warming might merely have served to exacerbate it.

Commercial fisheries were the mainstay of the Alaska economy in the years before the discovery of oil at Prudhoe Bay and the growth of tourism as a global economic engine, and commercial fisheries in Alaska were in dire shape in the 1970s.

The economics of the situation propelled the state toward better fishery management in the hopes of restoring depleted wild runs of salmon and big investments in hatcheries in hopes of artificially boosting returns.

Both have worked extremely well with an assist from warm waters in the Gulf of Alaska. The situation looked almost too good to be true by the 1980s with sockeye and Chinook production high in Gulf of Alaska watersheds, and the hatcheries starting to build up the production of pinks and chums.

Cook Inlet, the state’s most popular and most contested fishery for commercial and sport fishering, ended that decade with an average annual commercial harvest of 4.4 million salmon per year. The harvest for the past decade was under 3 million.

The Copper River, the state’s most famous sockeye salmon fishery, followed a similar pattern.

The consensus of fishery scientists credits the rise at the end of the 20th century to warmer water due to what has come to be called the “Pacific Decadal Oscillation” or PDO, an unexplained shift in the temperature of North Pacific waters first identified in the 1990s. It appears unconnected to general global warming.

Fishery scientists generally credit the PDO with the difference in salmon production from 1925 to 1945 – when catches were generally high – and from 1946 to 1975 – when catches were generally low. It also gets some credit for some of the smaller, annual oscillations in salmon harvests.

PDO

Readers can compare the PDO graph above from the National Oceanic and Atmospheric Administration (NOAA) to the harvest graph from the NPAFC at the top of the story and draw their own conclusions.

The big warming in the 1930s – warmer than any shift up through 2015 – matches nicely with the big harvests in the same time period, but other parts of the two graphs are not as well linked.

Ocean cooling in the early 2000s clearly did not have the same effect on salmon as it appeared to have in the ’50s, ’60s and ’70s. And though there is a correlation between spiking water temperatures in the mid-1950s and a jump in harvests, that warming did not boost production nearly as much as the warming that began in the late 1970s.

Meanwhile, water temperatures are largely out of sync with the high salmon production from the late 1990s through the mid-2010s when waters in the North Pacific were noticeably cooler than in the general period from 1975 to 1985, a period during which there were significant changes affecting the species underway.

Scientific management of wild salmon took some big leaps forward in these years, and the Alaska Department of Fish and Game started the business of farming the ocean – ranching as they like to call it – with state-funded salmon hatcheries now largely run by commercial fishing interests.

Basically, in a state where salmon fishing was one of the biggest economic engines, a concerted effort was made to begin managing all Alaska rivers and streams for maximum salmon production with even more salmon production to be added with the aid of hatcheries.

Escapement goals – the number of salmon escaping the nets of commercial fishermen in order to spawn – were progressively pushed upward as fisheries managers gathered more and more data on how many salmon they could crowd into Alaska rivers to maximize the number of eggs in the gravel, the number of fry later emerging from that gravel and thus the number of little salmon going to sea where the vast majority of them have always been destined to die.

Salmon production is really just a numbers game. If you manage a river system so that spawners produce only 100,000 little salmon return to the sea with 95 percent of those destined to die, only 5,000 adults would return. But if you could set things up for 1 million little salmon to head back to sea with that same death percentage of 95 percent, you get back 50,000.

Alaska has now been managing salmon to meet the ever-more objective for about five decades, and to say that the state has been successful is something of an understatement.

The average annual harvest of Alaska salmon in the 2010s, the decade that just ended, was nearly four times the average annual harvest in the 1970s. 

The big jump from an average catch of 48.3 million a year for the 1970s came in the 1980s when nicely warm ocean waters helped Alaska produce an average of 122.4 million salmon per year.

But with Alaska’s production hatcheries coming online in the 1980s and management getting ever better, production went up again in the 1990s, even as waters cooled, and up again in the 2000s and up yet again in the 2010s:

• 122.4 million on average per year in the ’80s.
• 157.5 million on average per year in the ’90s.
• 167.4 million on average per year in the 2000s.
• 171.2 million on average per year in the 2010s.

As production in Alaska, which is in the best geographic position to farm the North Pacific, has gone steadily up, production in Canada and the Pacific Northwest has gone steadily down.

The Committee on the Status of Endangered Wildlife in Canada, a Canadian government entity, has now designated four stocks of British Columbia Chinook and two stocks of steelhead trout, an ocean-going cousin of the salmon, as endangered. Another three stocks of Chinook are considered threatened and one more of special of concern.

In the U.S., upper Columbia River, NOAA notes that spring-run Chinook have been listed as endangered while three other stocks returning to the river system that forms the boundary between the states of Washington and Oregon are listed as threatened along with the Chinook of Puget Sound and the upper Willamette River.

The federal agency also considers the coho of the lower Columbia River and of the Oregon coast to be threatened.

Dams have for decades been blamed for these salmon declines, but ground-breaking research by David Welch at Kintama Research Services in British Columbia points toward a different problem, a deteriorating ocean pasture.

Welch and colleagues have documented a 65 percent, coastwide decline in the production of Chinook. Given that the returns of the big fish to the wild and undeveloped rivers of Alaska have fallen as much as the returns of the big fish to the dammed rivers of the Pacific Northwest, Welch said, it’s pretty clear the big problem the fish face is not in freshwater but in the ocean where they spend most of their lives.

Some have pinned the declines on growing predation by marine mammals and sharks. University of Alaska researchers have found evidence that at least as regards a falling population of Yukon River Chinook, sharks might be playing a big role.

Elsewhere, the evidence for predation is thin and Ruggerone – noting the steadily shrinking size of Gulf of Alaska-origin sockeye that has been underway for years and the coastwide problems of Chinook – has hypothesized that the big problem is competition for food with all those bountiful and voracious pinks out competing all other species of salmon.

The problem, he argues, is one of too many fish battling for too little food, the marine parallel to the Old West problem of starvation due to too many cattle on the range. The idea that overabundance can cause problems is an old, old ecologic reality that goes back to early conservation Aldo Leopold’s observations of mule deer on the Kaibab Plateau in northern Arizona and southern Utah. 

After predators were hunted to extinction in that area, the deer population exploded, ate everything in sight, destroyed its own range, and then crashed. The work was fundamental to ecological understandings of both carrying capacity and those so-called “trophic cascades,” changes in ecosystems that spark a reordering of most of the creatures in those ecosystems.

In this context, there are valid, scientific arguments to be made that Alaska fishery management policies, aided by the state’s salmon hatcheries, are helping to fuel the now big swings in annual, North American salmon production, and that these policies have led to an Alaska takeover of an inordinate amount of the salmon pasture in order to grow pinks, or “humpies” as Alaskans just as often call the smallest salmon.

God forbid the Canadians, who are increasingly upset about the low numbers of salmon returning to their streams and river, stumble on this hypothesis because the situation as it exists now has been generally good for the 49th state, though not perfect.

Approximately 233 million salmon were caught in Alaska last year, but they amounted to only about 390,000 tons or about 3.7 pounds per individual salmon.

The 2020 catch was but 51 percent of that at 118 million salmon, but the tonnage of about 235,000 was 65 percent of 2021 with the average weight of a 2020 Alaska salmon hitting 4.4 pounds.

There is a long-term trend in the North Pacific as to the size of salmon decreasing as the number of salmon there increases. One cannot help but wonder about the economic consequences of this in a world where market prices rise with the size of the fish.

Intrafish reported Norwegian farmed salmon trading at about $3.10 per pound for sizes 6.6 to 8.8 pounds, $3.14 pound for sizes 8.8 to 11 pounds, $3.23 per pound for sizes 11 to 13.2 pounds, and $3.64 per pound or slightly more for sizes over 15.4 pounds in October of last year as the Alaska fishing season was wrapping up.

The Alaska Department of Fish and Game later reported that the most plentiful of the state’s fish – pinks – went for a statewide average of 37 cents per pound in the months before with chums at 77 cents per pound, sockeye at $1.34 per pound and coho, aveage weight 6 pounds, at $1.45 per pound, about half the price of a farmed salmon of the same size.

Alaska Chinook, however, averaged 11 pounds in size and attracted a Norwegian-size price of $5.82 per pound. Unfortunately, the statewide harvest of just over 266,000 kings amounted to about a tenth of a percent of the statewide harvest of nearly 234 million salmon, about two out of every three of them a pink.