Salmon run
 Grizzly Bears Catching Salmon on YouTube – Nature's Great Events: The Great Salmon Run |
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Bald Eagle catches salmon on YouTube – BBC Nature's Great Events - The Great Salmon Run |
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The Great Salmon Run on YouTube – BBC Nature's Great Events
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Nimbus Hatchery Fish Ladder on YouTube
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Life Cycle of Salmon on YouTube
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Life Cycle of Salmon on YouTube – Discovery Channel
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The Salmon's Lifecycle Atlantic Salmon Trust
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Sockeye Salmon Run 2010 on YouTube
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Spawning salmon constructing a redd on YouTube
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Raising salmon on YouTube
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Salmon life cycle song on YouTube
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The salmon run is the time when salmon, which have migrated from the ocean, swim to the upper reaches of rivers where they spawn on gravel beds. After spawning, all Pacific salmon and most Atlantic salmon die, and the salmon life cycle starts over again. The annual run can be a major event for grizzly bears, bald eagles and sport fishermen. Most salmon species migrate during the fall (September through November).
Salmon spend their early life in rivers, and then swim out to sea where they live their adult lives and gain most of their body mass. When they have matured, they return to the rivers to spawn. Usually they return with uncanny precision to the natal river where they were born, and even to the very spawning ground of their birth. It is thought that, when they are in the ocean, they use to locate the general position of their natal river, and once close to the river, that they use their sense of smell to home in on the river entrance and even their natal spawning ground.
In northwest America, salmon is a keystone species, which means the impact they have on other life is greater than would be expected in relation to their biomass. The death of the salmon has important consequences, since it means significant nutrients in their carcasses, rich in nitrogen, sulfur, carbon and phosphorus, are transferred from the ocean to terrestrial wildlife such as bears and riparian woodlands adjacent to the rivers. This has knock-on effects not only for the next generation of salmon, but to every species living in the riparian zones the salmon reach. The nutrients can also be washed downstream into estuaries where they accumulate and provide further support for estuarine breeding birds.
Most salmon are anadromous, a term which comes from the Greek anadromos, meaning "running upward". Anadromous fish grow up mostly in the saltwater in oceans. When they have matured they migrate or "run up" freshwater rivers to spawn in what is called the salmon run.
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Wikipedia