The North Pacific Ocean is at this time home to more salmon than at any time in recorded history, and the residents of Seattle are worrying that their local sockeye, which once numbered in the hundreds of thousands, might soon be extinct.
The usual suspects are being blamed.
“Today the worry is that the fish can’t beat the combination of climate change that is warming the water in the lake and Lake Washington Ship Canal to lethal temperatures; urbanization of the lake; and surging predator populations gobbling juvenile salmon,” reporter Lynda V. Mapes wrote in the Seattle Times last week.
Predators are clearly a problem in the 34-square-mile lake in the heart of the city and warm water isn’t helping salmon survival, but the biggest problem might have been overlooked in The Times’ summary: ocean survival.
Ground-breaking research by Canadian scientists has suggested that ending West Coast salmon declines now isn’t nearly as simple as dealing with freshwater issues. The Canadians discovered that even where salmon streams are unsullied by the hand of man, as in parts of British Columbia and Southeast Alaska, Chinook – the big kings – are suffering declines similar to those of the disappearing sockeye of Lake Washington.
Their peer-reviewed study was published late last year in the journal Fish and Fisheries. Canadian David Welch and associates at Kintama Research Services in British Columbia reported that all along the North American West Coast, the numbers of Chinook – a long-lived species like sockeye – declined by 65 percent over the past 50 years due to changing ocean conditions.
Downward trends have also been seen in sockeyes and coho, or what Alaskans usually call silver salmon. All of these fish have something in common with kings; their young spend at least a year in freshwater before going to sea where they spend multiple years before returning to spawn.
Welch doesn’t dismiss the problems salmon face in the rivers and streams of the rapidly growing Pacific Northwest (PNW), where hydroelectric dams have long interfered with spawning migrations of adult fish and increased the dangers of predation on young fish heading to sea.
But what his research found was that this is not the deadliest threat to the region’s salmon.
“At the broadest level, the major implication of our results is
that most of the salmon conservation problem is determined in the
ocean by common processes,” he and his co-authors wrote. “Attempts to improve smolt to adult return rates by addressing region-specific issues such as freshwater habitat degradation or salmon aquaculture in coastal zones are therefore unlikely to be successful.”
Given the study’s challenge to the widespread and prevailing belief that PNW salmon would thrive if only hydroelectric dams were removed and people constrained, the research was heavily challenged. The paper spent more than a year in review with reviewers arguing the data couldn’t be right before finally accepting that it was sound.
All of this is coming at a time when Alaska and Russia are seeing record catches of salmon. There are no doubt lots of salmon in the ocean.
Part of this is clearly linked to warmer water. Scientists have known for decades that when the waters of the Gulf of Alaska are warm, salmon productivity in Alaska goes up and that in the Northwest goes down.
Fisheries biologist Steven Hare in 1996 coined the term “Pacific decadal oscillation” (PDO) to describe naturally fluctuating ocean temperatures reflected in coastwide shifts in salmon harvests along the North American West Coast.
“Major changes in northeast Pacific marine ecosystems have been correlated with phase changes in the PDO; warm eras have seen enhanced coastal ocean biological productivity in Alaska and inhibited productivity off the west coast of the contiguous United States, while cold PDO eras have seen the opposite north-south pattern of marine ecosystem productivity,” according to the National Oceanic and Atmospheric Administration (NOAA).
The causes of the shifts remain unknown. Some believe they have been compounded by the general global warming of the 20th century that is continuing in the 21st century.
This is not, however, the only change that has been underway in the Pacific in modern times. Man has also been tampering with the system by using hatcheries to add more salmon to the stew of ocean fishes and, particularly in Alaska, managing salmon for maximum abundance.
One of the chief results has been an explosion of pink salmon – the smallest and shortest-lived of the Pacific species. Pinks are the cheapest and easiest to raise salmon as they require no freshwater rearing and offer a quick turnaround in production.
The fish need spend only about 18 months at sea to reach spawning sizes of 3.5 to 5 pounds before returning to the hatchery.
Now the average, annual catch is 15 times as high at 45 million humpies, as Alaskans call them, and the value of these “wild-caught,” ranched salmon (Alaskans abhor the term “farmed salmon”) is put at $125 million per year in the Sound.
How Alaska’s ranching and management for maximum productivity is affecting the ocean ecosystem is becoming an issue attracting increasing attention as salmon runs to the south of the 49th state struggle.
Alaska and Russia have done such a good job with pink salmon that Ruggerone and Irvine estimated that about seven out of every 10 adult salmon in the ocean today are pinks, which along with getting a helping hand from hatcheries appear to enjoy a competitive advantage over other salmon in warmer water.
A team of scientists from the University of California, the University of Alaska, Canada’s McGill and Simon Fraser universities, Virginia Polytechnic Institute and State University, the Washington Department of Fish and Wildlife, the Alaska Department of Fish and Game, and GKV & Sons, an independent consultancy this summer warned the large numbers of pinks could be harming other salmon Pacific-wide. They reported steady declines in the average sizes of Chinook, sockeye, chum and coho since the 1990s with dramatic declines in the size of Chinook and sockeye starting in about 2000.
The approximately “5 billion hatchery salmon…released into the North Pacific each year…add to already high abundances of wild pink, chum, and sockeye,” they wrote. “While signals of conspecific and interspecific competition are increasingly evident, managers currently lack tools to help inform difficult decisions regarding hatchery releases. Tools that quantify the apparent trade-offs between the releases of one species and the impacts of size and productivity on conspecifics and other species are urgently needed.”
The linkage between the Nature study and the Welch study is clear.
Who would conduct studies to try to figure out how to manage the situation is unclear. The director of fisheries research for the Alaska Department of Fish and Game has said such studies are too difficult for his agency to undertake.
Critics of the Alaska hatchery program have, in turn, charged that is just an excuse for the agency’s unwillingness to pursue research that might produce results the agency doesn’t want to see.
The Alaska hatchery program was born of Fish and Game’s Division of Fisheries Rehabilitation and Enhancement (FRED) before being largely turned over to private, nonprofit aquaculture associations run by commercial fishermen after the state found the hatcheries too costly to operate.
Commercial fishermen, who catch nearly all the hatchery fish, were at first expected to support the costs of the hatcheries solely with a so-called “salmon enhancement” tax on their catches, but the state later gave the hatcheries themselves the authority to conduct “cost-recovery fisheries” to pay operating expenses.
The hatcheries now operate much like salmon farms in the rest of the world with the fish being raised to pay the wages and the salaries of hatchery operators. The only major difference is that any profit from the operations in Alaska goes into the pockets of commercial fishermen and not the employees of the hatchery.
This has been good business in areas with hatcheries, but possibly not so much in others both in and outside of Alaska.
“For sockeye salmon, North Pacific pink salmon abundance had a particularly strong negative association with body size,” the Nature study warned.
That in turn produces a negative association with value. Salmon are graded on size and quality with big, well-handled fish commanding the top price.
Smaller salmon also mean the females carry fewer eggs thus dictating more spawners are needed to maintain productivity. As with everything in nature, as the authors of the Nature study noted, there are tradeoffs and complications.
Whether one of the tradeoffs involves Alaska’s massive production of salmon lowering salmon production to the south is a huge question. But there is no doubt the state’s harvest is now massive.
State salmon catches that averaged under 50 million fish per year in the 1970s more than tripled to an average of about 180 million in the 2010s with hatchery fish, primarily pinks, regularly comprising a quarter to more than a third of the catch.
This was all fine when the food supply for salmon in the ocean was thought to be near inexhaustible, but that idea has increasingly come under question. And some in Canada and the lower 48 are starting to wonder if their salmon stocks could be paying a price for Alaska’s bounty.
In an email exchange on Tuesday, Welch noted that Lake Washington isn’t the only waterbody now suffering dismal sockeye returns.
Along with shrunken runs in “Puget Sound,” he wrote, “we could add the similar problems for all but one of the 20-plus sockeye populations in the Fraser River, plus the Redfish Lake sockeye issue in the Snake River, and those are being mirrored in multiple other parts of the coast, but not all.
“I have to think that the real location of the problem is farther away from the coast because 13 years ago we were working on exactly this problem in British Columbia and found using acoustic telemetry that sockeye smolt survival was quite high in the first four to six weeks of ocean life, but then dropped sharply at some later point in their life history prior to adult return.”
The Fraser, a river just north of the U.S.-Canada border, last summer witnessed the worst return of sockeye in its history. Despite the closure of sockeye fisheries, only 293,000 salmon made it back, according to the Pacific Salmon Commission.
From 1980 to 2014, the river averaged returns of almost 10 million sockeye per year.
At the limits
Sockeye in the Fraser, like those in Lake Washington and the Snake River drainage of the Columbia River system, are among the southernmost sockeye in North America. They are thus thought to be the fish most vulnerable to global warming.
How exactly this threat might manifest itself is unknown, but food competition could be one way. Intense, interspecies competition for food is a norm in marine ecosystems where big fish eat little fish with almost no regard as to species.
Alaska’s FRED program once wanted to undertake a “predator control study” in Tutka Lagoon near the southern end of the Kenai Peninsula to determine how many hatchery fry were being consumed by Dolly Varden char and herring, a prey of large salmon.
Seattle seems to be in some ways following the Alaska model for solving salmon problems. When the Lake Washington sockeye run first started to falter, a hatchery was built along the Cedar River.
With the hatchery having now failed to produce the desired results, scientists are studying the predators that kill an estimated 94 to 99 percent of sockeye fry in the lake before they get a chance to go to sea as smolts.
Fry-to-survival rates of sockeye are hugely variable, but the Lake Washington loss rates can only be described as high. Long-term monitoring of sockeye in Hidden Lake on Alaska’s Kenai show losses of 60 to 92 percent with a 20-year average of about 81 percent.
Still, in-lake losses of fry and out-migrating smolt can’t fully account for the overwhelming losses of returning Lake Washington sockeye.
The last three years set records for the worst runs the lake has ever seen. The 2018 return of 32,103 was the lowest on record before the disaster of only 17,411 fish in 2019. Last year slotted in between the two with a count of 22,950.
These are the numbers of fish counted coming through the Ballard Locks. If there were heat-related kills in the ship canal beyond or in the lake itself, the numbers would only shrink farther, but there have been no reports of major heat-related kills of fish in either place though there has been significant prespawn mortality among sockeye in the Cedar River, the lake’s main spawning tributary.
That might be due to heat stress, disease or a combination of the two.
The Cedar River hatchery has reported that a third to a half of the sockeye being held in holding pens waiting to be milked died in the 2010s and that in-river mortalities of fish left to spawn there also increased “dramatically.”
The loss of the young from those fish compounds the predation loss, but that still doesn’t fully account for the hundreds of thousands of sockeye missing at the locks.
Still, the possibility that the problem for Lake Washington sockeye is in the ocean runs somewhat counter to decades of environmental activism focused on hydroelectric dams and climate change in the region as the sole cause of salmon declines. Climate change might be part of the problem the fish face, but it does not appear as simple as the scary idea that salmon are now cooking in the waters of the lake.
A climate shift that favors warm-water fishes appears more likely. Naturally dominated by salmon, Lake Washington is now home to large populations of perch, bluegills, crappies, bass – largemouth and smallmouth – bullheads, sunfish and more.
All have been introduced into the watershed over the years, and they’ve recently been joined by walleyes and northern pike. All prey on young salmon, and some are notorious for their ability to tear through salmon populations.
The catch of a large pike in the lake in 2017 caused something of a stir.
“Watch Your Toes? Vicious New Fish Caught In Lake Washington,” Patch.com headlined at the time. A fish with a historic range that extended from Alaska north of the Alaska Range down through Canada and into the Midwest, pike have been transplanted and/or introduced throughout the West where they have regularly been implicated in decimating native salmon populations.
But pike would only add to the predator problems that were already facing Lake Washington sockeye thanks to humans tampering with nature in the old, fish-“stocking” way.
In one of the richest bits of irony in this story, it would appear most of the Lake Washington sockeye also owe their existence to ancestors transplanted from various PNW locations, including Cultus Lake in the Fraser drainage. Genetic testing has left open the possibility that there might have been a very small population of native fish using the lake’s Bear Creek, but the evidence is thin.
The genetics indicate that most of the salmon using the lake today trace their origins back to U.S. Bureau of Fisheries stocking operations from 1937 through 1954.
This is not the only irony, however.
Today’s predator problems are such that a reporter for Northwest Sportsman suggested Lake Washington might have been better habitat for salmon when the lake was something of a cesspool in the late 1960s and early ’70s.
“The system produced reliably high returns of as many as 400,000 spawners into the river in the 1960s and 1970s, at the end of the era when Lake Washington was thick with blue-green algae that hid the smolts from predators,” wrote Andy Walgamott.
“Following cleanup efforts, water clarity went from as little as 30 inches in 1964 to 10 feet in 1968 to up to 25 feet in 1990….(Predatory) native cutthroat (trout) and northern pikeminnow primarily but also nonnative bass, yellow perch and other species suddenly had the advantage over the young sockeye.”
Since sewage flowing into the lake was diverted to a treatment plant in the late 1960s, King County reported, “rapid and predicted water quality improvements followed, blue-green algae decreased and have been relatively insignificant since 1976.”
Cleaner water helped some fish thrive. The salmon in turn suffered.
Sport fishing for sockeye salmon in the lake has been closed for years, but the lake remains widely popular for fishing for cutthroat trout, largemouth and smallmouth bass, perch, and crappies despite warnings to limit consumption of those fish due to mercury contamination, according to the WDFW.
It appears unlikely the lake will ever host another sockeye fishery, and the Seattle Times suggested Lake Washington sockeye are headed for extinction.
The hatchery is no longer much help in stemming the decline.
From 2004 through 2013, King County records indicate, 70,000 to 75,000 sockeye per year on average made it back to the Cedar River with about 10,000 of those being captured to use for hatchery broodstock.
Since 2014, however, it’s been largely downhill and getting worse almost by the year. The total return to Cedar River fell below 8,000 in 2018, below 3,500 in 2019, and barely made 3,000 this year. Hatchery managers captured 2,000 fish, a number far below the goal, and left the rest to spawn naturally.
The hatchery fish, which are raised in a controlled environment where they don’t have to worry about predators or the water heating up when they are small, have been surviving in somewhat larger numbers than their relatives spawned in the wild, but not by much.
Meanwhile, the hatchery is looking at a troubled future. A $31 million fund set aside to build and operate the facility through 2050 is down to about $4 million, the Times reported.
The facility cost more than expected to build, and “we figured it would be $300,000 a year to operate, and it is double that,” hatchery project overseer Paul Faulds told The Times. With operating costs running at $600,000 per year, the remaining $4 million in hatchery funds will run out by 2028 – 22 years ahead of schedule.
Were this not enough, the hatchery now finds itself unable to obtain enough eggs to maintain full production because of the small returns of fish.
Seattle’s best hope might be that ocean conditions start shifting back toward a situation more favorable to PNW salmon than the fish in Alaska, but when or if that sort of shift might take place is impossible to predict.