Chinook Salmon. Photo by Dave Brenner/Michigan Sea Grant

Spawning/Migration of Pacific Salmon (Salmonidae)
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 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–making the round trip only once.

Salmon spawn in virtually all types of freshwater habitat, from intertidal areas to high mountain streams. Pacific salmon may swim hundreds, even thousands, of miles to get back to the stream where they hatched.

Only a small percentage of salmon live to reach their natal stream or spawning grounds. Since salmon do not feed once they leave the ocean, some will die on the way because they lack enough stored body fat to make the trip. Many will be caught in fishermen’s nets or swim through polluted waters near cities. Many must make their way over power dams, leaping up from one tiny pool to the next along cement stairstep cascades. In the tributary streams, waterfalls and rapids are steep and swift enough to eliminate all but the strongest. Otters, eagles, and bears stalk the salmon in shallow riffles. Once on the spawning grounds, the fish battle each other: females against females for places to nest, males against males for available females.

Threats to Pacific Salmon (Salmonidae)
Many salmon stocks are seriously threatened by what are called the “four H’s”: Habitat destruction, Hydroelectric dams on migratory rivers, over-Harvest of rare stocks, and competition with Hatchery fish. Some stocks are so severely reduced that they have been listed as endangered or threatened species under the Endangered Species Act.

:: Source: U.S. Fish & Wildlife Service

FAST FACT>>

The U.S. Congress established the Pacific Coastal Salmon Recovery Fund to contribute to the restoration and conservation of Pacific salmon and their habitats.