Oregon Effort Aims to Protect Endangered Wild Salmon in Pacific Northwest
By Rosanne Skirble
Eight hours a day, five days a week, Irene Nelson sits at a desk in front of an underwater window at the Bonneville Dam in Oregon and counts fish.
"That is a hatchery steelhead and it is going up. And that's a Chad going up. Two Chad. And that there is a hatchery Chinook salmon. And, that's a wild," she explains.
What Irene Nelson records in this dimly lit room is a tiny fraction of the salmon that journeyed through the Columbia River Basin, a vast watershed in the Pacific Northwest which encompasses thousands of kilometers of the Columbia and Snake Rivers.
Each click marks a salmon's successful trip up a so-called fish ladder, a stepped sluiceway designed to provide the fish an upstream passage through the dam.
"And there is a hatchery steelhead. Come on boys!" she exclaims.
Irene Nelson counts hatchery fish, those spawned in plastic buckets, incubated in trays and raised in concrete raceways. She also tallies wild salmon, which spawn in fresh water, migrate to the ocean and then return to their native freshwater streams to lay eggs and die.
Between 700,000 and 1 million adult salmon and steelhead migrate upstream, and from 30 to 50 million pass Ms. Nelson's checkpoint at Bonneville Dam downstream each year.
The official count helps managers track increases and decreases in salmon runs.
It also tells a story.
Fishery biologist Jim Lichatowich says for centuries the return of salmon provided an ecological feast of gigantic proportions.
"The salmon fed in the ocean and brought those nutrients back up the river and deposited them in the headwaters where the eagles and the bears, other birds ,other mammals fed on the carcasses," he explains. "Bears dragged salmon carcasses off the stream and up to the banks and actually deposited fertilizer for the trees that grew along the river. The carcasses that decomposed in the rivers spread nutrients throughout the aquatic food chain so that the next generation of salmon were fed by the bodies of their parents."
The salmon is a symbol of life in the Pacific Northwest. The ecosystem and human economies have thrived on it. But wild salmon are now extinct in 40 percent of their native rivers.
Human exploitation is largely to blame for the decline. In the late 1800s, canneries expanded demand for the fish. Newcomers also mined lands, logged forests, irrigated farms and grazed their livestock near fragile river banks. All contributed to the steady deterioration of the salmon's habitat.
And then, in the 1930s, came the dams. A wave of dam construction that continued for 40 years helped the region generate hydroelectric power and control floods. But dams also blocked river flow and created a major obstacle to salmon returning from the ocean.
Biologists and conservationists had long since recognized that to survive in such a radically altered habitat, the salmon was going to need some help. The first fish hatcheries were built in the 1880s.
Jim Lichatowich, whose book Salmon without Rivers relates the history of the Pacific Salmon, says hatcheries set up a very simple management scheme that traded habitat for hatcheries.
Rivers just became pipelines to get fish to the ocean and the reproduction and early growth of the salmon would be under human control in the rivers. And, once they got out to ocean, it was believed that the ocean was an unlimited grazing area for salmon. So, you might say that we socially constructed an ecosystem that really didn't exist. We created our own myth. We believed in this myth that we could replace rivers and natural salmon populations with hatcheries and artificial production."
Jim Lichatowich says that myth - man's control over nature - allowed for the destruction of salmon habitat. The region has more than 200 hatchery programs. Mr. Lichatowich says they are far too entrenched in commercial and sport fishing to be eliminated. But he thinks that hatcheries can play a different and more productive role in helping to help recover wild salmon.
"So we need to replace that factory metaphor and think of hatcheries as a stream, another tributary within the watershed," he says. "And, when you do that a whole together different set of questions arises and that is in this stream, what is the productive capacity of the natural stream, and is the number of fish released from the hatchery compatible with the carrying capacity of the river as a whole. What about the seasonal patterns of flow and temperature and how has that influenced the life histories of the animals?"
And, are there any indications of some hatcheries that are beginning to change to this mammal?
"Oh, sure some of the newer hatcheries that are trying to take an ecosystem or landscape approach to their operations, but we have a huge backlog of old hatcheries that are still operating since the beginning or at least for the last 50 years," says Jim Lichatowich. "Overhauling the whole system is going to require some major changes and some major commitments."
Jim Lichatowich says the life story of the salmon is embedded in a chain of habitats in the Pacific Northwest that extends all the way from Idaho to the Gulf of Alaska. In order to protect the endangered animals that live in those habitats, he says, we must step back and look at the landscape as a whole, and see how all the parts fit together.
From Portland, Oregon, I am Rosanne Skirble.
注释：
hatchery 孵卵处
Chad 乍得湖
fraction 小部分
Columbia River Basin 哥伦比亚流域
encompass 环绕
upstream 顺流而上的
spawn 产卵
incubate 孵卵
fishery 水产业
gigantic 巨大的
deposite 安置
carcass 屠体
ecosystem 生态系统
cannery 罐头厂
hydroelectric 水电的
obstacle 障碍
conservationist 自然资源保护主义者
tributary 支流
overhauling修整