Struggling Against the Current
by Robin Meadows
When it comes to wild salmon in the Pacific Northwest, people generally agree on only two things: These fish are in trouble, and it’s important to save them. After that, the conversation degenerates into a debate over the cause of salmon decline. Some insist the biggest problem is dams, others claim it’s fishing, and still others say it’s habitat loss. The salmon have no say, they just keep sliding toward extinction.
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| The Lemhi River in Idaho was once a prime salmon run. (Joel McNee/NRCS) |
The disappearance of salmon from the Columbia River, which flows between Washington and Oregon, is not up for debate. The Columbia was once one of the greatest salmon rivers in the world. Historical runs were enormous, with roughly 15 million adult salmon returning to spawn each year. But throughout the last century, wild salmon have dwindled there, and today’s runs are only a tenth of what they once were.
The Columbia’s salmon slump echoes a larger problem throughout the North Pacific. “Most of the wild stocks...have declined to very low levels and many are in clear danger of extinction,” says Daniel Goodman, Director of Environmental Statistics at Montana State University in Bozeman.
Another indisputable fact: Many factors are harming wild salmon. These include dams, fishing, habitat loss and degradation, and production of hatchery salmon that compete with their wild cousins for food. However, interest groups downplay each of these factors and point their finger at others to take responsibility for the salmon’s decline, and for their salvation. “Wild salmon recovery in western Washington is a biologically simple but politically difficult task,” says Billy Franks, chairman of the Northwest Indian Fisheries Commission, in a Seattle Daily Journal commentary.
Sorting out the politics of wild salmon recovery in the North Pacific is tricky because one important thing is not clear. No one really knows how much each factor contributes to the salmon’s imminent demise, says Goodman. But we do know that salmon have far-reaching ecological impacts, which means that if we lose them, we will lose a lot more than just the fish themselves.
Ecological Importance of Salmon
The term Pacific salmon generally refers to seven species
in the family Salmonidae: chinook, chum, coho, pink,
and sockeye salmon, and cutthroat and steelhead trout.
They range from pink salmon, which average three to
five pounds, to chinook, which average 10 to 15 pounds
but can get much bigger—up to 135 pounds, according
to the Washington Department of Fish and Wildlife.
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| Sockeye are one of seven species commonly called Pacific salmon. (Timothy Knepp/USFWS) |
The basic life cycle of salmon starts when they hatch from eggs laid in streams and rivers. The young begin growing in fresh water and estuaries, finish growing in the ocean, and finally migrate back to their birth sites to spawn and start the whole cycle over again. This cycle differs slightly within each species and among populations because salmon habitat is vast and varied, spanning more than 1.5 million square miles of fresh and marine waters. The Columbia Basin alone has more than 1,000 miles of rivers, and extends from the mouth of the Columbia River to its headwaters in Washington, Oregon, and Idaho, and even into parts of Montana and Canada.
Because Pacific salmon live in a tremendous variety of habitats, there are hundreds of different populations, or stocks. Even if two stocks are the same species, one cannot be substituted for another because each has adapted its own niche. Some stocks, for example, spawn near the Columbia’s mouth and overwinter in the sea. Other stocks spawn in tiny streams in mountain headwaters and spend their first winter in fresh water.
Many Pacific salmon stocks are already extinct, and 26 are federally listed as threatened or endangered. The issue goes beyond saving the salmon themselves, because the fish play a “crucial role in supporting overall ecosystem health,” according to John Cederholm and his colleagues in a 2000 Washington Department of Fish and Wildlife report titled Pacific Salmon and Wildlife—Ecological Contexts, Relationships and Implications for Management.
Salmon are vital to the Pacific Northwest’s ecosystems; they are a major source of nutrients for many animals, and also for some plants. When migrating salmon drift ashore or are eaten by animals, they cycle back into the land nitrogen, phosphorous, and other nutrients that are continually washing out of the land and into the ocean. Salmon directly link ecosystems that are half a world apart, all the way from their inland spawning grounds to their ocean feeding grounds, which extend north of the Aleutian Islands and to the Asian side of the Pacific.
Today, wild Pacific salmon runs are so diminished that they are transporting only a small fraction of the nutrients they once brought back to the land. The mass of the salmon now returning to Washington and Oregon rivers has dropped by an estimated 97 percent, from roughly 250,000 to 7,500 tons per year.
This loss of returning salmon affects the many animals that depend on them for food. “[Salmon are] a keystone species to the productivity and biodiversity of the ecosystems of the North Pacific Basin,” say Cederholm and his colleagues. Of more than 600 common wildlife species in Washington, 137 are known to depend on salmon in some way. Salmon eggs are eaten by 22 species, including salamanders and common mergansers. Young salmon in fresh water are eaten by 45 species, including osprey and river otters. Salmon in salt water are eaten by 58 species, including Caspian terns and killer whales. Spawning salmon are eaten by 16 species, including harbor seals and black bears. And salmon carcasses are eaten by 83 species, including shrews and grizzly bears. There is an even greater depth to these numbers, because many species eat salmon at more than one stage. For example, grizzly bears eat both salmon carcasses and spawning salmon. Moreover, many species depend on salmon indirectly: American dippers, for example, eat the aquatic insects that live on decaying salmon.
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| Kodiak brown bears eat salmon. (J & K Hollingsworth/USFWS) |
Not surprisingly, ecosystems that lose their salmon can also lose the wildlife that depend on them. For example, after several years of low sockeye salmon returns in Kamchatka’s Lake Dalnee, both zooplankton and zooplankton-eating fish decreased substantially (by 30 percent and 45 percent, respectively). Similarly, as salmon declined in Glacier National Park’s McDonald Creek, so did bald eagles. In 1981, the creek had more than 100,000 spawning salmon and more than 600 bald eagles; by 1989, the salmon population had collapsed and there were only 25 bald eagles—a 96 percent reduction in less than a decade.
It may come as a surprise, however, that low salmon returns can also affect forest ecosystems. Riparian forests that grow along spawning streams can get a substantial fraction of their nutrients from salmon. In an Alaskan watershed, the leaves of trees and shrubs near spawning streams get about a quarter of their nitrogen from salmon. In the coastal forests of southeast Alaska, trees near spawning streams grow faster than trees far from spawning streams.
In the most extreme cases, some forests may depend almost entirely on salmon for their nutrients. Siberia’s Ussuri River is not a likely place for a forest because it is very cold, gets little sunshine, and has no significant mountains upstream to supply nutrients. Forests grow there nonetheless. Some biologists believe that these forests’ main nutrients come from the salmon and other anadromous fish that migrate from the Pacific Ocean to spawn in the Ussuri.
No Easy Fixes for Wild Salmon
Concerns about overfishing salmon in the Columbia date
back to the mid-late 1800s, when commercial fisheries
hauled in phenomenal catches. Fish wheels scooped up
migrating salmon by the millions—a single fish
wheel caught 70,000 pounds of salmon in just one day
in 1913. Although fish wheels were banned on the Columbia
after 1935, the salmon immediately faced an emerging
threat: dams. From the early 1930s to 1975, 11 large
federal dams were built on the Columbia River for hydropower,
flood control, and navigation, with a hazardous side
effect on salmon—dams can block migration and
keep salmon from reaching spawning streams.
Between fishing, dam construction, and other threats, salmon continued to decline. At the time, the answer to reversing this decline seemed obvious—simply supplement the wild populations with hatchery-raised fish. This approach has been so popular that there are now more than 100 salmon hatcheries in Washington and Oregon. But even though Columbia Basin hatcheries produce 100 to 200 million young salmon each year, wild Pacific salmon are still in trouble.
Hatcheries
Worse, many conservation biologist believe that hatcheries
have done wild salmon more harm than good. Today, hatchery
fish comprise 90 percent of the Columbia Basin salmon
run. The influx of hatchery fish has kept fishing rates
artificially high; consequently, commercial fishers
have continued to catch wild salmon even though their
populations have been dropping.
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| Hatchery salmon compete with their wild cousins for food and habitat. (USFWS) |
Another problem is that hatchery salmon can outcompete wild salmon for territory and food, and will sometimes eat smaller wild salmon. Moreover, fish raised in hatcheries may be adapted to captivity, so they are less suited to natural conditions. For example, hatchery salmon are used to being fed and are not used to avoiding predators. If there is a genetic basis for these behaviors, interbreeding between hatchery salmon and wild stock may make the wild population less suited to natural conditions too.
Despite all these drawbacks, hatcheries are still releasing salmon in the Columbia Basin. Fishing interests see hatcheries as mitigation for smaller salmon runs. “[Hatcheries] were established to compensate the regional fishing industry for the permanent loss of habitat above dams,” says the Pacific Coast Federation of Fishermen’s Association. “Hatchery programs in the Columbia are extremely important to maintaining the fishing industry.”
Now so-called “conservation hatcheries” have become the trend. The idea is to make hatchery salmon more like wild ones by, for example, building hatcheries that mimic natural conditions, or by using wild-spawned salmon for hatchery broodstock. While some interests champion “conservation hatcheries,” so far they are little more than a buzzword. Science has not yet demonstrated whether they will help or hurt wild stocks.
Habitat Loss and Degradation
Spawning salmon need cold, clear, fast-flowing water,
but every year there’s less and less of that in
the Columbia Basin. Urban development, logging, grazing,
and farming can all increase the erosion of silt into
streams, which can suffocate salmon eggs. These land
uses can also decrease the riparian forests that provide
the shade that keeps the streams cold. Warmer waters
can kill salmon eggs, and are linked to disease outbreaks
and parasite infestations. “[The salmon’s]
long-term problems are rooted primarily in habitat degradation,”
says the Northwest Indian Fisheries Commission.
Not everyone agrees. To take just one example, many farmers in Skagit County, Washington, oppose restoring riparian forest on their property to enhance salmon spawning habitat. “Most farmers argued that agriculture was not the main cause of salmon decline...they believed it was fishing and in particular tribal overfishing,” says Sara Jo Breslow in a 2001 EPA report titled Farmers’ Perceptions of Salmon Habitat Restoration Measures: Loss and Contestation.
Moreover, although biologists say studies show that riparian restoration would benefit salmon, some farmers question the underlying science. They claim that restoring riparian forest would actually degrade salmon spawning habitat because woody debris from the trees would fall into the streams, making them slow down and meander, which in turn would cause more erosion and so increase the sediment in the water. Instead, the farmers suggest other ways to save the salmon, such as paying fishermen not to fish.
The Dam Question
The Columbia Basin has more than 24 large dams on its
main rivers and hundreds of dams on its tributaries.
Besides blocking salmon’s upstream migration,
dams can kill young fish that pass through the turbines
on their way to the sea. Dams can also destroy salmon
habitat by, for example, creating deep pools that inundate
the spawning and rearing grounds. Today, salmon can
no longer reach a third of their historical habitat
in the Columbia Basin. In addition, the Columbia River
has become what amounts to a series of long, narrow
reservoirs that provide little spawning or rearing habitat.
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| The Chief Joseph Dam sits on the Columbia River in Washington State. (USACE) |
The biggest controversy over dams and Pacific salmon centers on the Snake River, which begins in Idaho and joins the Columbia River in Washington. While the Snake once produced 40 percent of the Columbia Basin’s salmon run, stocks there began declining faster after the construction of large dams in the 1960s and ‘70s. Today, many of the Snake’s wild salmon stocks are extinct or in trouble.
In 2001, more than 200 scientists called for breaching the earthen portions of four federal dams on the lower Snake River. Fishing interests agreed, claiming that the dams account for 90 percent of the fish killed while yielding only small benefits: specifically, that the dams generate only about four percent of the region’s hydropower and provide irrigation water for relatively few farms. “There is no question that the hydropower dams themselves have had by far the greatest impact [on Columbia Basin salmon],” says the Pacific Coast Federation of Fishermen’s Association.
To Fish or Not to Fish
But again, not everyone agrees. Save Our Dams founder
Tom Flint says the real problem is fishing, not dams.
In 1999, Save Our Dams supported an unsuccessful bill
that would have banned most commercial salmon fishing
in Washington. “For every ten salmon returning
to spawn, six are taken by ocean harvest,” claims
Flint. “Only in the United States can you buy
an endangered species for $2 a pound, continue to commercially
harvest them, while at the same time spend $1 billion
per year to save them.” Estimates for how much
is spent on salmon recovery efforts vary and Flint’s
is on the high side, but even so, the cost is undeniably
considerable.
Fishing interests counter Flint’s claims, asserting that all fishing—commercial, recreational, and tribal—causes only about five percent of human-related salmon deaths. Rather than banning salmon fishing, they advocate “selective harvest” of healthy salmon stocks. The idea is to avoid catching at-risk wild stocks by, for example, timing the fishing seasons or using nets with particular mesh sizes.
However, no one knows if selective harvest will work. In any case, biologists stress that it is critical to make sure that at-risk wild salmon are not caught. “We should stop killing and eating the very salmon that we are trying to save,” says the Washington Department of Fish and Wildlife’s Cederholm. And for a declining wild stock, any harvest at all is overharvest, points out Montana State University’s Goodman.
Science and Salvation
In the debate over how to save the Columbia Basin’s
wild salmon, many interest groups support their stance
by citing only the science they like, and ignoring the
rest. Save Our Dams’ Flint, speaking about dam-breaching
on the Snake River, says “Dam-breaching is based
on voodoo science.” The Pacific Coast Federation
of Fishermen’s Association, which believes hydropower
dams have affected Pacific salmon, says “the science
is clear, the impacts are clear, the actions we must
take are clear.” And Sara Jo Breslow, in her 2001
EPA report, notes that “[Farmers] discussed science
as if it belonged to particular groups, saying things
like ‘our science,’ ‘their science,’
or ‘the tribes’ science.’”
But the biggest problem facing wild Pacific salmon right now may be the fact that the science really isn’t clear about who—or what—is to blame, which makes it impossible to move beyond all the finger-pointing. “Just enough is known about these various factors affecting Columbia Basin salmon to raise, alternately, dire suspicions or rosy expectations,” says Goodman. “Not enough is known...to define what mix of interventions will be the most efficient at achieving the goal of recovery.” In other words, better science may be the wild Pacific salmon’s only hope.
—Robin Meadows is a contributing editor of
ZooGoer.
ZooGoer
33(1) 2004. Copyright 2004 Friends of the National Zoo.
All rights reserved.
