Extreme Measures

Resource for Grades 8-12

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Video

Running Time: 5m 04s
Size: 29.5 MB

Learn more about the Nature film Salmon:Running the Gauntlet.

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Major corporate support for NATURE is provided by Canon U.S.A., Inc. Additional support is provided by the Lillian Goldman Charitable Trust, Filomen M. D’Agostino Foundation, the Corporation for Public Broadcasting, and the nation’s public television stations.

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This video adapted from Nature describes efforts to protect salmon by killing and re-locating predators. Examples include paying bounty hunters to fish pikeminnow, trying to relocate terns and cormorants and using non-lethal bullets to scare away sea lions. The segment concludes with a look at how scientists are counting current numbers of salmon passing through Bonneville Dam, along the Oregon-Washington border.

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Background Essay

In the past 200 years, the number of salmon in the Pacific Northwest has decreased dramatically due to a combination of natural and human-related factors. Many species of salmon in the Pacific Northwest are listed as threatened or endangered on the Endangered Species list. In the Colorado River, the salmon population is approximately 3% of what it was in the early 1800s. Some factors that pose threats to salmon are rising stream and river temperatures, due to climate change; pollution, which is damaging and sometimes deadly to salmon and their prey; overharvesting (through commercial fishing, etc.); dams on the rivers, which obstruct passage to spawning areas; and natural predators. Four species that provide serious threats to Pacific Northwest salmon are: double-crested cormorants, Caspian terns, sea lions and pikeminnow.

Pikeminnow: Scientists believe fish hatcheries (which produce, raise and release salmon into the wild) and dams have directly contributed to increases in pikeminnow populations. Hatcheries release large quantities of juvenile salmon into the water at once. Salmon often get disoriented after passing through the fish ladders at the dams and fall victim to pike minnow, which wait below the dam and feed on the salmon as they pass through. In 1991, the northern pikeminnow management program began, which pays bounty hunters to fish for pikeminnow, in order to protect endangered salmon species. As a result of the program, more than 3 million pikeminnow have been removed from the Columbia and Snake Rivers and the amount of juvenile salmon and steelhead consumed by pikeminnow has decreased by 50%. Note: A bounty involves the payment of money to encourage people to remove a species that has been identified as a danger to others. This stems from a long tradition of paying people to remove species that pose a threat. Some species that have been targeted by bounty hunters include: coyotes, crows, foxes, gophers, rats, rattlesnakes, skunks and wolves.
Caspian Terns and Double-Crested Cormorants: Cormorants and terns on East Sand Island at the mouth of the Columbia River eat about 20 million young salmon a year. The island, owned by the US Army Corps of Engineers, houses the largest known nesting colonies of double-crested and Caspian terns in the world (approximately 13,600 breeding pairs of cormorants and 8300 breeding pairs of Caspian terns in 2010). The US Army Corps of Engineers is currently planning to relocate half the tern population to other sites in Oregon and California by 2015.
Sea Lions: Sea Lions eat thousands of salmon and steelhead populations each year, while the fish are waiting to enter the ladders at Bonneville Dam on the Columbia River. In order to protect salmon and steelhead populations, officials first authorized the use of non-lethal means to scare away the sea lions, as depicted in the “Extreme Measures” video resource. Despite these efforts, however, the problem persisted and, in March 2008, the federal government gave fish and wildlife officials in Washington, Oregon and Idaho the permission to kill up to 85 sea lions each year below Bonneville Dam in order to control the population. In addition to killing the sea lions, states try to relocate sea lions to aquariums and zoos, when possible. This decision to kill one species to protect another has been challenged by the Humane Society and other animal advocacy groups, who state that the sea lions are not as big a threat to salmon as other factors, such as overfishing by humans.

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Discussion Questions

What do you think about the methods officials are using to protect salmon from pikeminnow and sea lions?
Do you think officials should build a new island for the terns and cormorants in order to keep them from eating salmon? If not, what actions (if any) do you think should be taken?
How are scientists keeping track of their progress in increasing the salmon population?

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Transcript

NARRATOR: a number of juveniles will die at each dam. And survivors often find themselves disoriented in the turbulent tailwaters below…

Where they’re easy prey for pikeminnow, a native fish whose population has exploded in the warm, slow water between dams.

In response, authorities have enlisted the help of… bounty hunters. Hundreds of fishermen like Tim Histand now fish for pikeminnow because pikeminnow have a price on their heads.

TIM HISTAND: Looks too easy doesn’t it? This one’s worth five bucks.

The more pikeminnow Tim turns in, the more each is worth – up to $8/fish. A few have special tags, swimming jackpots worth $500 each.

Tim does so well at it, he can shut down his contracting business for five months every year and hunt pikeminnow full time.

TIM HISTAND: Last year I caught 3,650, I think, something like that. The year before, I had 4,400. So, in the last five years, in the last five years I’ve probably caught close to 20,000 of them.

Since the bounty hunt began, over 3 million pikeminnow have been captured and turned in. It’s a multi-million dollar a year campaign, one we’ll probably be paying for as long as the dams are in place.

The 150 miles between Bonneville and the sea are regularly dredged to keep the channel open for transports and barges.

Some of what’s been removed has been piled near the mouth of the river as part of a sandy island, which has attracted the world’s largest breeding colony of Caspian terns.

Together with their young, these terns consume millions of juvenile salmon a year, mostly hatchery fish released on a deliciously predictable schedule.

To protect young fish, the government is building the terns an alternative island farther offshore. If that’s successful, maybe something similar can be done for the terns’ neighbors.

13,000 pairs of cormorants and their very hungry chicks.

“SUDS” SODERSTROM: We have cormorants now in huge, huge numbers. We have a whole new species of cormorant that’s moved into the Columbia system to attack these fish.

For returning Columbia Basin salmon, Bonneville is the threshold between the wild, open ocean and the managed, engineered river.

Salmon hold for up to 24 hours at the foot of the dam, as they prepare to enter the fish ladders.

The pause isn’t just inconvenient. It’s sometimes deadly.

“SUDS” SODERSTROM: The sea lions have figured it out. And they figure sometimes four or five percent of the adults are caught by the sea lions at Bonneville Dam. They’re not talking about the other 130 miles the sea lions are working down through here, too.

About a billion dollars a year are now committed to Columbia River salmon recovery, inspiring extreme measures to protect the investment’s return.

During the salmon run, boats patrol the width of the Columbia below Bonneville, trying to drive sea lions back to the sea.

In 2008, 35,000 non-lethal cracker-shots, rubber bullets, and seal bombs were fired at one protected species on behalf of another.

Fish that escape predation and enter the ladders pass by the counting window at Bonneville.

Here, we measure how well they, and we, are doing.

Lately, about a million fish a year, both wild and hatchery-born, travel past the window. That’s less than 8 percent of an average run a hundred years ago.