A sockeye salmon, Alaska’s big money fish/Craig Medred photo

The Alaska Department of Fish and Game believes global warming will continue to smile on the sockeye salmon of Bristol Bay and has forecast another huge return of the fish for next year.

The agency’s best estimate puts the 2021 flood of sockeye to the Bay at just over 51 million in a range of 38 to 64 million. The point predictions have often been high or low over the years, but the state has a very good record on forecasting the range.

If the run does hit 51 million, it will mark the seventh consecutive year in which returns have topped 50 million but fall shy of the 58.2 million fish that returned to the Bay this year. Those fish compromised the fifth-largest run in history.

Climate change has been credited but scientists worry that if the planet continues to warm rising temperatures could become a negative for sockeye, a coldwater species of fish.

To date, though, the change has been a big plus for the fishermen who profit from the harvest of sockeye and for the fish even though they are getting slightly smaller in size while increasing in number.

A 2013 examination of the size of sockeye at maturity since 1960 found the fish in all nine of the major river systems feeding the Bay had shrunk. They were just under an inch to nearly an inch and a half shorter in the Iliamna Lake drainage and two and a half to more than four inches shorter in the Wood River system, the peer-reviewed study published Evolutionary Applications in 2015 reported.

Smaller size means less weight which reduces the value of the fish to fishermen, but increased harvests have more than made up for the change.

A harvest of 43 million sockeye pushed the value of the 2019 Bay salmon catch to a record value of $306.5 million, according to Fish and Game. The catch was the second largest in history and came as somewhat of a surprise.

The total run for 2019 had been forecast at 38.7 million, but 56.5 million came back. Better survival of young fish in both the streams of the Bay and the waters of the warming Bering Sea and North Pacific Ocean were credited for the monster return.

Greener pastures

A study by University of Washington (UW) scientists published in the peer-reviewed Nature Ecology & Evolution last year said the warmer freshwaters in the Southwest corner of Alaska are now so productive more young sockeye need only spend a year inland instead of two before they are big enough to go to sea.

Once at sea, the fish also find a better pasture on which to graze.

“Earlier ice-off and warmer lake conditions are positively correlated with Daphnia spp. densities, a primary food source for juvenile sockeye and juvenile salmon growth,” the study said. “In the North Pacific Ocean, the primary rearing area for sockeye, there have been changes in surface temperature as well as upwelling and productivity. The Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO) are inter-decadal shifts in sea surface temperature and upwelling that are strongly correlated with sockeye productivity in Alaska.”

Daphnia are a large genus of small crustaceans commonly known as “water fleas.” The largest of them is less than a quarter of an inch and length and the smallest is invisible to the naked eye.

As rosy as the situation might appear now, the UW researchers led by Timothy Cline cautioned that an increasing shift toward “1.3 sockeye” – so-called because they spend a year in freshwater and three at sea before returning to spawn – could make the Bay subject to wider swings in the number of salmon returning each year.

“Diversity in age composition plays a key role in reducing variability in salmon runs, with importance for fishers, communities and industry that rely on annual salmon returns,” he and his colleagues wrote. “Age structure reduces year-to-year variability in runs to Bristol Bay by 50 percent compared to the scenario if runs were of a single age.”

The variability in the size of returns to the Bay has long caused marketing problems for processors, and those have only increased as high-value sockeye have transitioned away from canned salmon markets toward those for frozen foods.

The latter cannot be stored for as long as the former, and frozen salmon face stiff competition from farmed salmon that can be produced year-round in predictable quantities and delivered to markets on a flexible schedule.

Along with the potential market problems the loss of age-structure diversity could cause for fishermen and processors, it poses threats to the fish as well. A lack of diversity makes any population of animals less resistant to environmental changes.

Real-world lessons

In the midst of the COVID-19 pandemic, humans are now living this natural reality. If every member of the species lacked resistance to the disease linked to the newly evolved SARS-CoV-2 virus, billions would be dying, but genetic diversity ensures that some people are immune.

For salmon, the UW researchers wrote, “maintaining diversity in age structure is an important component of sustaining stable populations in the face of various anthropogenic and natural stressors, and should be a goal for conservation.”

Exactly how one might try to accomplish that in the Bay is an unknown. By changing the size of mesh specified for gillnets, fishery managers can to some degree alter the predominant size of the fish caught in the fishery, but it’s unclear how much such changes could do to increase the catch of 1.3s and minimize the catch of larger 2.3s and 1.4s.

And for now, the big returns to the Bay are generally considered nothing but good news.

As state fisheries biologists noted in their forecast, the 2021 predicted return is six percent larger than the 10-year average for the Bay and a whopping 45 percent bigger than the long-term average from 1963–2020.

Between the Bay and catches from nearby South Peninsula fisheries adjacent to the Bay, they expect a harvest of 37.37 million salmon, which is 13 percent greater than the 10-year average.

All of this will come as welcome news to fishermen who took a beating this year because of the pandemic. Food hoarding at the start of the crisis helped processors move an oversupply of 2019 salmon for which many thought they’d overpaid, but the costs of dealing with COVID-19 precautions for processing plants drove up operating costs, which left them worried about overpaying once again.

Largely as a result, prices paid fishermen plummeted. Fish and Game reported the season average sockeye price at 70 cents per pound, about half of last year.

That caused a wild swing in the value of the fishery. It dropped from the record value of $306.6 million last year to less than half that at $140.7 million this year.

The value still ranked “ninth in the last 20 years and was (only) five percent below the 20-year average of $147.8 million,” Fish and Game reported, but that was a measure in real dollars that fails to reflect inflation.

A $147.8 million catch today isn’t close to what it was 20 years ago. A national inflation calculator says the $147.8 million is now equal in value to a 2020 catch worth $223.5 million, or looked at another way, a $147.8 million catch in 2020 would have a value of only about two-thirds the same catch in 2000.

What happens to salmon prices next year remains a big unknown. The heavy impact the pandemic has had on the restaurant business is forcing many salmon farmers to transition into the retail market.

Given that the farmers now control more than 70 percent of the market, their sales largely dictate price. Wild Alaska salmon can still attract a slight premium over farmed salmon in some markets, but the wild label has lost some of its value as farmed salmon have become the world’s most commonly consumed salmon.