The rivers of the North Pacific Ocean/U.S. Academies of Science
Officials with the Alaska Department of Fish and Game say they’re sticking with a forecast for another boom year for pink salmon despite a first-ever, international survey of the Gulf of Alaska notable for the species of salmon in short supply – pinks.
“The Secret Lives of Salmon: Where are all the pinks?” headlined the Vancouver Sun in mid-March. The Canadian newspaper was one of a handful of news organizations regularly tracking the voyage of the Russian research vessel Professor Kaganovsky as it sampled the Gulf in an effort to start sorting out what happens in the black box of salmon life history.
Believes is the operative word.
About all that has been known for sure about salmon at sea up to now is that 80 to 98 percent of the young enter the ocean never to return. And that pink salmon, despite an average ocean survival-rate of only about 3 percent, are the most common of the six Pacific salmon in the sea due to the fact they breed like proverbial rabbits.
Nearly 138 million of them will return to Alaska streams and rivers this summer if the official forecast of the Alaska Department of Fish and Game is correct. The international team of scientists aboard the Kaganovsky estimated only about 4.5 million pinks are in the Gulf at this time.
Organized by a Canadian scientist and backed by the International Year of the Salmon group, the voyage of the Kaganovsky brought together scientists from Canada, Russia, Japan, Korea and the U.S. Alaska did not directly participate.
The state that likes to brag about its world-class salmon management was far enough removed from the project that when Deputy Fish and Game Commissioner Forrest Bowers, the man who oversees commercial fisheries for the state, was asked about the Professor Kaganovsky, he confessed he’d never heard of it.
Curious scientists
Plenty of the scientists working for Bowers, however, were watching the voyage carefully. A couple had been asked by colleagues from lower 48 to develop sampling protocol. Others couldn’t avoid being curious as to what the ship would find
Richard Brenner, who leads salmon forecasting efforts for the state, said Monday that some of the data collected during the voyage is intriguing, but that it is hard to sort out what it means.
“The problem,” he said, “is that survey has only been done once. We don’t have a great historical context to look back on.”
It could, for instance, be perfectly normal for large numbers of pink salmon to be missing from the central Gulf at this time of year and for coho salmon, a far less abundant species, to outnumber them about three to one.
Scientists need time to try to sort the meaning in the wealth of data collected by the Kaganovsky, he said, and even then, they will be looking at nothing but the photographs of a number of frames in a movie.
A lot more frames are needed to start to figure out what the entire show is all about.
Like a lot of other salmon biologists, Brenner would like to see the survey become an annual event, but that appears unlikely. This year’s $1.2 million project to recognize the Year of the Salmon largely came together only because of the tireless efforts of retired-in-name-only Canadian researcher Richard Beamish, a 77-year-old grandfather of Pacific fisheries research probably best known for his discovery of acid rain in North America.
In a Seafood West Business Summit in Campbell River, B.C. last September, Beamish pointed to skyrocketing catches of wild Pacific salmon and a need to answer the question of what appears to be driving Pacific production upward.
“This catch is so large that [it] will shake up the science all around the North Pacific while people try to figure out what has happened,” The Columbia Valley Pioneer recorded him saying at that gathering.
Pacific catches in recent years are wholly out of line with historical harvests levels, cannot be fully explained by changes to fishery management or hatchery production, and reflect a shift in production areas with increased rates of ocean survival for Alaska and Russian salmon boosting numbers as a whole even as salmon from the Pacific Northwest struggle.
So many pink salmon showed up in Russian streams and rivers last year that processors couldn’t handle them all and unknown numbers were wasted as litter on the beaches and roads despite a harvest reported as a record-breaking 650,000 metric tons.
Alaska produced 510,000 metric tons in 2013 with a state record catch of 272 million salmon – more than double the 100-million-fish yardstick that for most of the 20th Century defined a good season in first the Alaska Territory and then the 49th state.
The Alaska Department of Fish and Game has forecast a catch of more than 213 million salmon for this year in keeping with a decade-long average of 181 million. That in turn is an increase from averages of 167.4 million in the 2000s, 157.5 million in the 1990s, and 122.4 million in the 1980s.
The New York Times might read those numbers to mean that “in an era of climate change and pollution,” there is a “dwindling catch” of Alaska salmon, but the reality is the opposite.
A warming north has to date smiled on the state’s fisheries and particularly pink salmon. About 65 percent of the forecast Alaska harvest for this year is expected to be pinks, a significant number of them hatchery fish.
The pink wave
The missing pinks have caused a fair bit of discussion among fishery scientist.
Vladimir Radchenko – the executive director of the North Pacific Anadromous Fish Commission based in Vancouver, British Columbia, Canada, and the chief scientist for the salmon on the project, this week told the Times Colonist newspaper he believes the pinks might have been south of the survey area.
Radchenko’s estimate would indicate the survey area contained less than 9 percent of the Ruggerone-Irvine estimate of 665 million salmon per year in the Pacific.
Given that weather messed up the neatly planned grid search of the Gulf, however, large numbers of pinks could also been missed east and north of the search area, although so little is known about the specific movements of mature salmon in the ocean that nobody is certain of where to expect to find them.
More is known about the movements of young salmon entering the Gulf of Alaska. Most of them are pushed north and west by currents as they emerge from streams and rivers in British Columbia and Alaska.
“The Alaska Coastal Current is a narrow, wind- and freshwater-driven current that flows in a counter-clockwise direction and dominates the flow along much of the continental shelf,” researchers from the National Oceanic and Atmospheric Administration (NOAA) wrote after their Gulf investigations. “These currents provide a near-continuous connection along the coast from British Columbia to the Aleutians that provides an advective or migratory pathway for early life stages of many fish species such as salmon, whose juveniles migrate along the shelf, and a number of groundfish species, whose eggs or larvae are released along the slope and
transported to downstream nursery areas.”
Those nursery areas are largely in the far Western Pacific.
How exactly the growing fish return from there the North American coast is less clear, but the general belief is that they catch a ride for at least part of the way on the eastward flowing North Pacific Current, which has been better tracked since the Fukushima nuclear disaster in Japan in 2011.
They reported continued tracking of the signal from a point far west of Vancouver Island to “where the large-scale circulation diverges into the northward-flowing Alaska Current and the southward-flowing California Current…. subject to pronounced variability on interannual to decadal time scales.”
If that is true, scientists might want to ask islanders for some help in sorting out the very complicated salmon picture in the Pacific.
Head scratcher
Brenner admitted he didn’t like Radchenko’s ratio of pinks to salmon numbers as a whole in the Gulf, but added, “I don’t know what to make of it.
“It’s a huge area,” he said. “It’s mind-boggling in size,” and salmon are temperature-sensitive creatures. Shifting ocean-water temperatures could shift locations of pink salmon.
And the simple reality of science is that it would be foolish for Alaska to abandon time-tested methods for forecasting salmon returns that while not always perfect as to exact numbers are very good at narrowing the range of possible returns.
The range this year spreads from a low of about 77 million pinks to a high of about 170 million. The bulk of the return is expected to come from Kodiak Island and Prince William Sound where hatcheries have created fishery that historically didn’t exist.
Brenner said the Kaganovsky sampling could have could have simply caught an accurate snap shot of what is expected for the state’s Panhandle where the forest is a weak 18 million, about half the 10-year average. Last year’s Southeast harvest was also weak. The problem appears to be with freshwater or nearshore survival of young pinks, but the specifics of what is happening are not known.
A joint effort between the state and NOAA’s Auke Bay Laboratory has allowed for spring sampling of out-migrating pink salmon juveniles in the region for years. Numbers were low in 2017 and lower still last June and July.
“The extremely low juvenile abundance index in 2018 was unexpected given that pink salmon (spawning) escapements in 2017 were generally good and escapement goals were met…,” the state forecast says.
It goes on to note freshwater survival problems at Auke Lake, one of the few sites in Southeast where adults and juveniles are both fully monitored. The lake is adjacent to the NOAA lab.
“The escapement of 10,711 pink salmon at Auke Creek in 2017 produced only 31,540 out-migrating fry in spring 2018,” it reported. “The fry-per-spawner ratio of 2.94 was the second lowest on record and well below the long-term average for the odd-year brood at 13.42 fry per spawner. In addition, the midpoint date of pink salmon fry out-migration at Auke Creek in 2018 (April 20) was four days later than the historical average (April 16) and nine days later than the average migration midpoint date of the last five, odd-year brood fry (April 11). The overall midpoint date of pink salmon fry out-migration at Auke Creek has shifted earlier over time at a rate of almost a half day per year, but this year’s later timing likely reflects below average temperatures in the Juneau area from February through March.”
The fry going to sea in 2018 also headed for a Pacific starting to warm above the norm again, a factor that is thought to have reduced Southeast returns from 2014 to 2016 although there are indications that it did the opposite in other parts of Alaska.
How this all works is unknown, but the answer is out there somewhere.