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Winter sets in at Onco's redd. A light blanket of snow
covers the ground. Thin, jagged sheets of ice cling to the banks where water
meets the shore. To look at this silent and apparently lifeless scene, you'd
never know what's going on within the gravel of the redd. Yet new life is
The hatchlings stay under the gravel. Onco, by Valentine's Day, is a homely and helpless little creature called an alevin. Her eyes are huge compared to the size of the rest of her body.
An orange yolk sac, sticking out from her belly, contains a balanced diet of protein, sugars, vitamins and minerals. As Onco grows, the yolk sac gets smaller.
Then one night in March, Onco slips upward through the gravel and emerges as a tiny fish called a fry. She's about the length of a fir needle and not much fatter.
Her eyes are still bugged out, and she avoids sunlight. She stays in shallow pools near the edge of the creek, where the current is not so strong.
Onco is tiny and she must be very quick. As she darts around feeding on even tinier creatures, she is wide open for sudden death. Fry are easy prey for trout and other large fish. Ducks and herons, even crows, devour fry.
Some chinook fry mature early. They migrate to the ocean in the first May or June of their lives. Others, like Onco, take their time. They stay in fresh water for one more full spin of the seasons before heading out to the Pacific.
Through her first summer, Onco pokes around her shallow home creek. In the fall, with colder water, she lets the current take her downstream. She's in no hurry and makes several stops along the way. Root wads, fallen trees and boulders make good resting and feeding places. By the time winter sets in, she finds herself in the Middle Fork of the Salmon River.
Onco is now about the length of a human adult's finger. Fish her size are called fingerlings. Scales protect the side of her body. The scales are covered by a slimy layer of mucus that protects Onco from disease and helps her slide through the water as if she were greased. She has faint vertical stripes along her silvery sides to help her hide from predators.
Onco is big enough now to be more of a hunter herself. She snaps up mosquitoes and other insects that come near the water surface. She nabs an ant unlucky enough to have fallen into the stream.
Her mouth is important not only for eating but for breathing as well. She takes in water through the mouth and forces it out through the gills on each side of her head. The feather-like gill filaments are full of blood vessels which - like the lungs in humans - take up oxygen and release carbon dioxide.
Onco doesn't have ears but she can hear. Low frequency sound waves vibrate through the water to a row of small holes along each side of her body. These holes open to nerves that let her "hear" danger. Salmon have nostrils and a good sense of smell. They can smell predators and food.
Onco can smell home, too. As Onco works her way from the spawning site, she senses where she been. She's learning how to get back, years later. This is called homing. Biologists are not exactly sure how it works. Somehow, the unique chemical qualities of Onco's home stream become lodged in her memory.
Onco must always be alert. In the summer of her first year, a kingfisher perched on a branch above her takes aim and dives. Thanks to Onco's big protruding eyes, she has good vision. Just as the bird hits the water, Onco darts away. She escapes. Not every young salmon is so quick or so lucky.
In fact, only about 10 percent of the eggs in a redd make it through the fry stage. Conditions for Onco and her redd-mates are better than average. Fifteen percent of the eggs grow into fry and survive that first spring and summer. Of the original 5,000 in Onco's family," only 750 are still alive and feeding.
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