Onco's growth slows in the winter of her
first year. Food is less abundant, and she needs less. Her body is idling,
waiting for another spring. The snowpack builds in the mountains.
In late April, snow starts melting. Spring rains begin. The water level rises and the annual spring runoff sweeps young salmon downstream.  Onco drifts
backward with her head upstream. She travels mostly at night to avoid predators
who hunt by sight. As she goes, she feeds on midges, worms and snails. Her
fingerling stripes slowly fade. She is changing inside, too, to make the
transition from fresh water to salt water. With these changes she is called a
smolt.
From the Middle Fork, Onco enters the Salmon River. Then she comes to the Snake, a bigger river that forms the border between Idaho and Oregon. Great crowds of smolts from other tributaries join her in a mass migration to the sea, as if they were rushing out of separate classrooms into one main hall toward recess. Mingling with Onco now are smolts that look like Onco but got a different start in life. Instead of hatching in the wild, they are the offspring of adult salmon whose eggs and milt were combined at a fish hatchery. They grew to be fingerlings in man-made rearing ponds. Spared the hazards of the wild, a greater percentage of them survived. 
But now, released in real streams, they face the same predators and
natural perils that Onco does. And they're not yet as sharp at hiding or finding
food as she is.
Hatchery-bred salmon raise the total numbers of returning salmon. But they also compete with wild fish for food and habitat. Because of their genetic diversity, wild salmon are more resistant to disease and carry the mix of genes that are critical to long-term survival of the breed. 
The Snake River runs northward, brown and swift. Suddenly the river is no
longer rushing. Onco has entered the reservoir upstream from Lower Granite Dam.
This is the first major barrier to her swift migration out to sea. A salmon is
designed to expect an unbroken spring flush to the ocean. Before dams, Onco's
trip out might have taken three or four weeks. Now it could take closer to two
months.
To speed their trip, many smolts are caught in pens at Lower Granite Dam and loaded into barges for a free ride downriver to below the last dam. Onco, ever wary, avoids capture and must do it the hard way. 
Beyond Lower Granite Dam on the Snake River, she finds other dams: Little Goose, Lower Monumental and Ice Harbor. When the Snake joins the Columbia River, there will he four more: McNary, John Day, The Dalles, and Bonneville. These dams were all built within the last 50 years and they have been terrific - for people. Dams make electricity by holding back water and then running it through turbines. Falling water spins the turbines to generate electricity that is clean - no smoke, little pollution - cheap and abundant. Locks at the dams enable tugs and barges to navigate all the way to Lewiston, Idaho. Dams also hold back water to irrigate farms during the dry summer months and help prevent flooding downstream. From Onco's point of view, however, dams are not at all terrific. The Columbia River becomes a series of flowing lakes instead of the continuous fast river she would prefer. Squawfish thrive in the slower water conditions and they eat smolts so do walleye and bass. 
Just as dangerous for Onco is the act of passing each dam itself. At Lower Granite, a fish screen catches Onco just in time and guides her away from the whirling blades of the turbines. At another dam the water is high enough that it is spilling freely over the dam. Onco is stunned for a second by a fifty-foot drop into the churning pools below. But she regains her senses in time to avoid scavenger gulls that circle and squawk in the air above her, looking for an easy meal. Onco's luck holds on this dangerous downstream trip. At each of the eight dams, about 10 to 15 percent of the smelts don't make it. But Onco does. To help salmon along, more screens and better bypass systems are being installed at the dams. From April to June, when smolts need faster flows, extra water is released from reservoirs upstream. People who would otherwise want to save that water- to irrigate farms, float barges and generate power- have to adjust. Everybody helps pay for salmon passage. When the electric utilities set aside water to help salmon, for example, it means there is less water for power when people need it the most. Electric rates go up. Efforts to move young salmon safely past the dams are meant to strike a balance between the needs of people and the needs of salmon. NEXT: Click here for Part 4 |
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