The aptly named “humpback salmon” in its spawning glory/John R. McMillan, NOAA photo
While West Coast Americans – Alaskans among them – worry and fret about farmed Atlantic salmon escaping to invade the Pacific Ocean despite decades of failed stocking efforts aimed at helping them do so, the Norwegians, Scots and other Europeans are facing a real and significant problem with an invasive Pacific salmon – the ubiquitous Alaska humpy.
The smallest of the Pacific salmon, the humpy – or pink salmon – is by far the most common species in the 49th state. Of the 224.6 million salmon caught in Alaska last year, 63 percent, some 114.6 million, were pinks, according to the Alaska Department of Fish and Game.
And Northern Europeans are now worried the highly adaptable and voracious humpy could become a common species in their coastal waters.
Blame the Russians.
They brought pinks from Sakhalin Island in the Pacific Ocean to the White Sea in northwest Russia in late 1950s and stocked them with hopes of creating new salmon runs, writes Odd Terje Sandlund at the website of the NTNU University Museum in Trondheim, Norway.
As with efforts to stock Atlantic salmon in the Pacific – efforts which date back to the early 1900s – the first Russian attempts with pinks were met with the same results: fail, fail, fail.
From 1958 through 1984, Sandlund writes, “the Russian aim of establishing self-sustaining pink populations in White Sea rivers did not succeed. During these years, almost all returning adult pink salmon to both Russian and Norwegian waters were the result of the Russian stocking program, with very few cases of natural reproduction.”
The Russians, however, didn’t give up.
“Further introductions in 1985, 1989 and 1998, based on fish from further north in the Russian Pacific, resulted in the establishment in Russian rivers of quite abundant odd-year stocks and less abundant even-year stocks,” Sandlund reports. “The subsequent appearance of pink salmon in Norwegian waters is a result of natural reproduction in Russian rivers in the White Sea area. Eventually, self-propagating odd-year populations of pink salmon were also established in rivers in eastern Finnmark.”
The successful Russian fish came from the Sea of Okhotsk on the western side of the Bering Sea from Alaska. Early summer spawners, they proved well suited to the White Sea, according to the International Council for Exploration of the Seas (ICES.)
A “single pink salmon egg-transfer from an odd-year population resulted in the establishment of local self-reproducing populations in the White Sea rivers of Murmansk and Archangelsk regions of Russia with the adult returns fluctuating between 60,000 to 700,000 fish during the period 1989 through 2009,” according to a white paper prepared by an ICES working group five years ago.
At that time, humpies were reported to have also established themselves in 11 rivers in northern Norway, but they were clearly not done with their colonization. The fish began showing up in streams all over Northern Europe last year.
“There was a formidable invasion in rivers all along the Norwegian coast with more than 11,000 pink salmon being caught or observed in 272 rivers,” Sandlund wrote. “Spawning was observed in many rivers along the coast. This last winter, fertilized eggs, fry with partly absorbed yolk sac, and fry in the process of smoltification, have been collected as far south as Bergen, and they have also been caught throughout northwestern Europe.”
Colonials
Alaskans are well familiar with the roaming instincts of humpies. Since a serious ocean-ranching program began in Prince William Sound in the late 1970s, hatchery salmon produced there have strayed into most of the streams on most of the many islands and the mainland in that 15,000 square mile area.
“The level of hatchery salmon strays in many areas of PWS are beyond all proposed thresholds (2–10 percent), which confounds wild salmon escapement goals and may harm the productivity, genetic diversity and fitness of wild salmon in this region,” state fisheries biologists warned in a 2012 paper published in Environmental Biology of Fishes.
Last year, PWS hatchery fish started showing up in significant numbers in the streams of Kachemak Bay and lower Cook Inlet to the north of the Sound, but given that pinks are native to Alaska waters, there has been little concern expressed but for a few citizen activists and, of late, the Kenai River Sportfishing Association and some other non-commercial fishing interests.
They have asked for a Board of Fisheries review of plans to add more hatchery pink salmon to the Sound. Commissioner of Fish and Game Sam Cotten, a former commercial fisherman whose sons now make money fishing pinks, ruled the request unfounded.
“From the beginning of Alaska’s salmon fishery enhancement program, it was recognized that salmon stray and that hatchery stocks would stray,” he wrote in defending his position.
The state’s “regional planning teams” for hatcheries have already discussed the issue, Cotten said, and “furthermore, while there were relatively high numbers of PWS hatchery-produced salmon found in several recent sampling events in lower Cook Inlet streams, not enough information is currently available to determine whether their presence threatens a fish or game resource.”
The Norwegians – faced with an invasion by a non-native species – take the straying of pink salmon differently. At the moment, they are encouraging Norwegian fishermen to catch every pink salmon they can and studying how they might kill pink eggs and alevins in river gravels.
As Sandlund notes, Norway is faced with what is likely to be a continuing problem because of the Russian created “pool of potential invaders in the Barents Sea and the North Atlantic. The history of pink salmon in this region has demonstrated quite poor homing to the river where they were hatched.”
The full concerns for the North Atlantic are unknown, and Norwegian fears have so far focused on rivers and streams where the fish compete with native Atlantic salmon and trout for room on the spawning grounds and might compete for food.
Pinks are “aggressive on the spawning grounds and may stress and chase away the native spawners,” Sandlund wrote. “All pink salmon die after spawning, and whilst their decaying carcasses may contribute to fertilizing the river and cause increased production, it may also cause unfavourable oxygen conditions for the incubating eggs and alter entire ecosystems in unpredictable ways.”
Pink salmon fry are usually quick to exit the spawning streams, which should minimize food competition with other fish, Sandlund said, but “Russian scientists claim that pink salmon fry may remain in the river for longer periods, up to weeks, and that high densities of pink salmon fry do have a substantial negative effect on the density of Atlantic salmon juveniles.”
Problems at sea?
Europeans have yet to determine whether the pink-salmon boom of 2017 was an oddity or a warning of more to come, and thus the potential for significant ecological changes brought by the introduction of a new species are hardly worth discussion in Europe at this time.
U.S. researchers Gregory Ruggerone and Jennifer Nielsen have, however, warned of the “competitive dominance” of pink salmon in the ocean environment.
When they looked at a broad range of salmon studies in the early 2000s, they found that the “research consistently indicated that pink salmon significantly altered prey abundance of other salmon species (e.g., zooplankton, squid), leading to altered diet, reduced total prey consumption and growth, delayed maturation, and reduced survival, depending on species and locale.”
In Scandinavia and the countries of the United Kingdom, where Atlantic salmon are already struggling to maintain themselves, that could be a major concern. In Alaska, where salmon populations in general have grown significantly since ocean waters in the North Pacific warmed around the start of the 1980s, food competition between salmon has not as yet attracted much discussion.
Hillstrand, a Homer-area woman whose family has been in the commercial fishing business for decades, said her efforts to try to get state officials to even talk about the possibilities of competition between salmon species and the risks of straying fish have been dismissed.
The regional planning teams (RPT) that Cotten promoted as the hatchery pink-salmon watchdog wouldn’t even consider the inter-regional straying of PWS hatchery pinks into Cook Inlet, she said.
Hillstrand provided emails showing she asked to have the topic added to the agendas of both the PWS RPT and the Cook Inlet RPT. It made neither. Her efforts to find out exactly what sort of hatchery reviews the RPTs have undertaken also proved difficult, she added.
“Unless a member of the public physically attends these meetings, this ‘open public process’ originally designed to disseminate information to the interested public so they can understand, comment or take action, is essentially a closed process with only the aquaculture boards and the processors present with access to the documents under review,” she said in an email.
All of the latter entities are primarily interested in producing more pink salmon in Alaska. The processors are on record saying they would like to see a harvest of 70 million humpies per year from the Sound alone – up from the 33- to 56-million per year now.
Alaska officials, unlike those in Norway, do not seem at all concerned about any possible downside to increased numbers of humpies. Hillstrand was concerned about it enough, however, to take three days of her time and, at a cost of $1,200, make a trip to Cordova where she stayed for two days to attend the Prince William Sound RPT meeting earlier this year.
“I was allowed 5 minutes to speak…,” she said. “I brought up the straying issue we were having in Cook Inlet and explained why this needed to be addressed. Not a word was mentioned about this issue during the meeting.
“There were no other members of the public present, and no one else spoke.
“Later, I was talking to a lady member of the Chamber of Commerce who was sitting with Sam Rabung (of Fish and Game) in a bar. She mentioned the RPT members told her that ‘some lady’ had been to the meeting ‘causing trouble.”’
Hillstrand confessed to being the lady, but said she wasn’t and isn’t trying to cause trouble.
She went to Cordova, she said, “in hopes this would be an agenda item taken seriously by the powers designed to comprehensively plan our Alaska salmon resources with a wild fish priority.”
Hillstrand believes the process for protecting wild salmon in Alaska is broken. Sound fishermen making money off hatchery fish think otherwise. Aside from a few state biologists who talk quietly about “density dependent” population problems, state officials seem unconcerned.
They are more worried about a possible invasion of Atlantic salmon, not a hint of which has ever happened in Alaska.
“Our concern is that Atlantic salmon could compete with native salmon and trout for spawning and rearing habitat,” the state of Alaska warns, echoing the fears Norway has about pink salmon. “Juvenile Atlantic salmon are notably more aggressive than Pacific salmon; this characteristic could enable them to outcompete Pacific salmon for food, but may also force native salmon off their natal rearing habitat.”
So far, Alaska; British Columbia, Canada; and the rest of the U.S. West Coast has been blessed by the fact Atlantic salmon have proven incapable of successfully colonizing the Pacific. The Norwegians can only wish they were so lucky with humpies.