Major study links pink salmon and ocean chaos

Part I of II

Pink salmon and the hatcheries helped boost their numbers to never-before-seen highs were Thursday singled out for disrupting the ecosystem of the North Pacific Ocean to the detriment of other species of salmon, seabirds, whales and more in a peer-reviewed study published in the journal Marine Ecology Progress Series (MEPS).

The study titled “From diatoms to killer whales: impacts of pink salmon on North Pacific ecosystems” concluded that “the evidence is consistent and strong that pink salmon can exert competitive dominance for common-pool prey resources shared by four forage fish species, all five species of Pacific salmon and steelhead trout, and 11 species of seabirds.

“It further indicates that pink salmon can have a strong influence on ecosystem structure and function by, for example, initiating pelagic trophic cascades.”

A trophic cascade basically begins with one species consuming so much of the food supply on which many species depend that the populations of other species start toppling. Scientists from Alaska and Australia in 2018 first implicated pinks in a trophic cascade that led to wrecks of short-tailed shearwaters in odd-numbered years from 2007 to 2013. 

The birds summer in Western Alaska and winter in Australia. The study was controversial when published but has gained more credence over time.

The conclusions in the latest study put a team of scientists led by independent, Seattle-based researcher Greg Ruggerone at odds with the Alaska Department of Fish and Game which has held that there is no way to tell if a boom in pinks fueled by the state’s focus on maximum-sustained-yield (MSY) management and a billion young pink salmon pumped out of industrial-scale hatcheries each year has anything to do with declines in king, sockeye and coho salmon, let alone trophic cascades.

After hearing this assessment from the state agency five years ago, the then Alaska Board of Fisheries, which had been appointed by commercial fisherman-friendly former Gov. Bill Walker, voted 4-3 to allow the Valdez Fisheries Development Association (VFDA) to up its ocean farming operation by another 20 million pink salmon eggs per year. 

When the Kenai River Sportfishing Association managed to force the Board to reconsider the hatchery issue four months later, Bill Templin, the state’s chief fishery scientist, appeared before the Board with an 84-screen PowerPoint presentation that explained the complexity of the ocean environment. He then argued that given the tangle of interactions between dozens of different species of fish, not to mention birds and marine mammals, no one could prove pinks were a problem.

The Board subsequently voted against a proposal to cap the production of salmon produced by private, non-profit, largely commercial fishermen-controlled hatcheries originally set up in the 1970s to produce fish to be shared by all Alaskans.

Manufactured versus wild

The hatcheries have since become businesses in their own right. Hatchery operations run by the commercial-fishermen-controlled Cook Inlet Regional Aquaculture Association (CIAA) now harvest more fish to pay for hatchery operations than are caught by Cook Inlet commercial fishermen who still pay assessments to the association. 

When the so-called PNP hatchery system was first set up, those assessments were intended to cover the costs of operating hatcheries to produce fish for all Alaskans. The hatcheries never contributed many salmon to non-commercial fisheries, but they became a bonanza for commercial fishermen in some areas of the state, most notably Prince William Sound, which over the years became a pink salmon factory.

As a result of the humpy explosion in the Sound, the hatcheries now generate hundreds of millions of dollars in economic output, according to a report prepared for the Alaska Seafood Marketing Institute by the McKinley Research consultancy.

And though nonprofit businesses in name, the hatcheries are profitable for the people running them.

McKinley found the 3,800 people now involved in the commercial hatchery business in the state in 2019 earned  $239 million or about $62,895 per person per year. That’s about $10,000 shy of twice the $36,787 the U.S. Census reported as the average for workers in Alaska in 2019, very close to twice what the average commercial salmon fisherman made that year, and almost three times the earnings of the average fish processing worker. 

Because of the jobs and revenue the hatcheries generate, they are today strongly supported by residents of the communities of Cordova and Valdez, but the hatcheries owe much to the promotional efforts of Seattle-based fish processing businesses.

In 2010, the Pacific Seafood Processors Association, an industry trade group, and three of the then-biggest processors operating in Alaska – Trident Seafoods, Icicle Seafoods and Ocean Beauty Seafoods – pushed for a greater than 60 percent increase in hatchery output.

“From 2000-2009 the average statewide hatchery pink returns were 32.6 million in even years and 55.9 million in odd years – in both cases about 40 percent of total pink returns,” they wrote in an “Open Letter to Alaska Hatcheries.”

“We would like production to increase to 70 million in both even and odds years over the next five years, which would bring hatchery production to roughly 50 percent of that total.”

Hatchery production has yet to reach those goals, especially in even-numbered years when pinks are less productive than in odd-numbered years. The harvest of hatchery pinks in 2021 totaled about 57 million, according to the state’s annual hatchery report. The 2020 harvest was less than half that at about 25 million, according to the state. 

But the overall, statewide harvest was boosted by wild-spawned fish some of which are hatchery fish gone feral. Most of the streams in the Sound now contain hatchery fish, and though they aren’t nearly as productive as wild fish, they likely add to pink numbers.

Pink salmon harvests, according to state data, now average about 150 million in odd-numbered years and are near 70 million in even-numbered years. The state reported a catch this year of 148 million despite processors facing a pink salmon glut closing plants early and some gillnet fishermen trying to avoid catching pinks because of the record low prices being paid for the fish.

The processors have close links to the Division of Commercial Fisheries within Fish and Game. The Division was until this year tied to a $16 million contribution from the processors association for “targeted research” aimed at studying pink salmon straying in Prince William Sound and the annual ratios of pink salmon returns per spawner, “an important measure of productivity and fitness.

“It is particularly important that hatchery operators and processors continue their support of the project, both for financial reasons as well as showing a commitment to maintaining this ground-breaking research that is designed to directly address questions about the Alaska salmon hatchery program,” Fish and Game said in 2018. “Processors had initially committed to 5 years; we hope they will continue their same level of support for the remainder of the project.”

Battling opinions

State research shifted attention away from studies of the ocean interactions of salmon which had first attracted attention in the 2000s when a decline in the size and number of Chinook salmon returning to Alaska streams and rivers became impossible to ignore. 

Chinook are the biggest of the salmon species and the fish Alaskans simply call “kings.”

A state task force was eventually set up to study why the fish were fading, and one of the theories to come out of those discussions was the idea the new-found abundance of pinks was driving trophic cascades that because of food shortages led to smaller and fewer kings.

When Templin appeared before the Fish Board, he dissed studies pointing to pinks as a problem and dismissed the idea of studies of ocean interactions as so difficult as to be near impossible. Some scientists within the department privately disagreed but kept their opinions to themselves. Some now agree with much of what is in the new study published by MEPS, but none are talking about it publicly.

The notable exception would be Leon Shaul, a biologist who studied coho salmon in Southeast Alaska for decades. He retired from Fish and Game in 2019 is now among the co-authors on the new study, which says this of those king salmon Alaskans officially made the state fish 60 years ago:

“Collectively, this evidence (gathered since the 1990s) suggests that pink salmon may directly and indirectly affect Chinook salmon growth and survival by consuming the same prey and by altering the food web that supports small fishes, squid, and zooplankton
consumed by Chinook salmon.

“Chinook salmon harvests, abundances, and average body sizes in northern regions where freshwater habitat is mostly intact have been declining for several decades and several
studies have suggested Chinook survival and growth may be inversely related to pink salmon abundance at sea.

“We examined the time series of annual Chinook salmon commercial harvests in Alaska and British Columbia (Canada) from 1952 to 2021. Commercial harvests reflect fishing effort based on abundance predictions and fishery regulations and can provide a first-order approximation of abundance….Consistent with the hypothesis that pink salmon affect Chinook salmon, we found that harvest trends during the 70-year period were opposite those of pink salmon abundance trends.”

Simply put, the research shows that when pink salmon numbers go up in the ocean both the size and numbers of king salmon go down.

Coming next: A species-by-species breakdown of interactions