Salmon Essay

1318 Words6 Pages
The upriver salmon migration is one of nature's most exciting dramas. But to the five species of Pacific salmon (Chinook , chum, coho, pink, and sockeye), it is a long, strenuous, desperate race against time, with every obstacle taking its toll. Pacific salmon belong to a group called anadromous fish that includes Atlantic salmon, sturgeon, lampreys, shad, herring, sea- run cutthroat trout, and steelhead trout. These species hatch and live the first part of their lives in fresh water, then migrate to the ocean to spend their adult lives, which may be as short as 6 months or as long as 7 years. When they reach sexual maturity, they return to the freshwater stream of their origin to lay their eggs. Pacific salmon make the round trip only…show more content…
The male then moves alongside and deposits his sperm, called milt, over the roe. The female rakes her tail back and forth to cover the redd with loose gravel. She then excavates her next redd a short distance upstream. The process continues until all the roe and milt have been deposited. One pair of salmon may have as many as seven redds, with four or five being the average. The salmon die within a few days of spawning. The translucent salmon eggs range in color from pale yellowish-orange to dark reddish-orange. The color varies both by species and within species and is determined by water temperature, sediment composition, age, and other factors. The eggs vary in size from the tiny sockeye roe (average 1/4 inch or 5.6 mm) to the large chum roe (average almost 1/2 inch or 8.3 mm). Incubation time ranges from 5 to 10 weeks. The newly hatched fish are called fry, or sometimes sac fry because they continue to feed on the yolk sac attached to their bellies. Depending on water temperature, species, and other factors, they may stay in the gravel for several weeks before swimming up into the open water of the stream, where they feed on plankton and other tiny aquatic organisms. By the time they reach fingerling size (approximately 3 inches), most pink and chum salmon have begun the long journey downstream and out to sea. Sockeye, coho, and most chinook spend from 1 to 2 years in fresh water before heading out to
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