Chinook Salmon

Genus:  Oncorhynchus  
Species: tshawytscha

Chinook Salmon swimming through a lock

The Chinook salmon is an important keystone species of the Pacific Northwest. It is a vital food source for a diversity of wildlife, including orca whales, bears, seals and large birds of prey. Chinook salmon is also prized by people who harvest salmon both commercially and for sport.

The health of Chinook salmon depends entirely on your location – Alaskan stocks are very healthy, while those in the Columbia River are in danger. Protection of Chinook salmon is crucial to maintain healthy Pacific Northwest ecosystems and to provide a delicious food source for years to come. 


Description:  Chinook salmon are blue-green on the head and back. The sides are silvery. The tail, back and upper fin have irregular, black spots. There are also black markings around the gums. During the mating season the salmon develop a reddish tint around the back fins and tail.

It is possible to tell the difference between males and females. Male Chinook salmon have a distinctive hooked nose at the top of the mouth. Less noticeable is the male's ridged back. Females do not have a ridge.


Size:  Chinook salmon are big fish! They are the largest Pacific salmon species. On average, Chinook salmon are 3 feet long and approximately 30 pounds. But some Chinook salmon can grow to over 5 feet long and 110 pounds!


Diet:  Young Chinook salmon will eat small invertebrates, including crustaceans, and amphipods. Adult salmon dine on smaller fish. 


Typical Lifespan:  Chinook salmon live about 3-7 years. For the first year or so the juvenile salmon stays in freshwater habitat. Soon it will move to the estuaries and then the open ocean. Estuaries provide a lot of food and nutrients to the developing salmon. The fish will spend approximately 2-4 years feeding in the ocean before returning to the spawning grounds to breed and die. 


Habitat:  Chinook salmon utilize many different habitats during their lives. Adults lay salmon eggs in fast moving, freshwater streams and rivers. Juvenile salmon spend some time in the freshwater streams before moving to mixed salt and freshwater estuaries. As the salmon reach adulthood, they move out into the open ocean.


Range:   Chinook salmon live in the colder, upper reaches of the Pacific Ocean. They live around the coasts of Alaska, western Canada, Oregon, Idaho, Washington and northern California. Chinook salmon can also be found in Russian and Japanese waters.

Chinook salmon breed in the freshwater rivers and streams of the Pacific Northwest. Chinook salmon have been introduced into numerous water bodies including the Great Lakes, where it is not native. 


Life History and Reproduction:  Chinook salmon are diadromous, which means that they spend part of their life in the salt-water of the ocean and the other part of their life in freshwater rivers and streams. Chinook salmon are born in freshwater streams and they travel to the open ocean to grow into adulthood. At reproductive maturity, they will swim back to their birth stream and produce young. 

When an adult Chinook salmon reaches maturity at about 3-7 years of age, it makes the long migratory journey back to the site of its birth. After so many years, some salmon can be hundreds of miles away from their birth stream.

The time of the breeding depends on the river and population of salmon. Typically, they breed in the summer and autumn.

At their birth stream, male and female salmon pair up to breed. The female digs a nesting hole (also called a redd). She deposits thousands of eggs in the redd before the male releases his sperm. After mating, the male and females stand guard over the eggs to protect them from predators. Chinook salmon burn a lot of energy migrating to the nesting grounds, breeding and protecting the eggs. Both parents will die before the eggs even hatch.


Threats to Chinook Salmon:

Chinook salmon are listed on the Endangered Species List. They are endangered in the Columbia River tributaries and California breeding sites and threatened in a range of rivers and streams throughout Oregon, Idaho and Washington states.  

 

National Wildlife Magazine Articles:

Orcas on the Edge

Where Wild Salmon Still Spawn

 

Resouces:

Stormwater Management and Recovery of Puget Sound Chinook Salmon (PDF) 

 

Sources:

NOAA Fisheries Office of Protected Resources

NOAA Fisheries Office of Protected Resources

Pacific States Marine Fisheries Commission

University of Michigan's Animal Diversity Web

Alaska Department of Fish and Game

U.S. Fish and Wildlife Service

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