Chinook salmon
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[Photo] A Chinook Salmon in the hands of a fisherman. The Chinook or King Salmon is the largest salmon in North America and can grow up to 58" long and 126 pounds. This Chinook salmon specimen shows the jaws drawn into a curved "kype", a secondary sex characteristic typical of many male salmon around spawning time. From: http://www.usgs.gov/features/lewisandclark/ChildrenWebSites.html

The Chinook salmon (Oncorhynchus tshawytscha) (derived from Russian чавыча), is a species of anadromous fish in the salmon family. It is a Pacific Ocean salmon and is variously known as the king salmon, tyee salmon, Columbia River salmon, black salmon, chub salmon, hook bill salmon, winter salmon, Spring Salmon and blackmouth. Chinook Salmon are typically divided into "races" with "spring chinook", "summer chinook", and "fall chinook" being most common. Races are determined by the timing of adult entry into fresh water. A "winter chinook" run is recognized in the Sacramento River.

Appearance
The Chinook salmon is blue-green on the back and top of the head with silvery sides and white ventral surfaces. It has black spots on its tail and the upper half of its body; its mouth is dark gray. Adult fish average 33 to 36 inches (840 to 910 mm), but may be up to 58 inches (1.47 meters) in length; they average 10 to 50 pounds (5 to 25 kg), but may reach 130 pounds (50 kg). The current sport caught World Record is over 99 lbs 6 oz. and was caught by Mrs Ingrid Oeder from Germany, guest at the Kermode Bear Fishing Lodge, in the Skeena River(Terrace), the fish was eventually released after being weighed and measured. A replica of the fish can be found on display in Terrace and is accessible by the public. The IGFA recognizes a 97 lb, 4 oz. specimen caught in the Kenai River, Alaska in 1985. Even larger, the commercial catch world record is 126 pounds caught near Petersburg, Alaska in a fish trap in 1949 (Scott and Crossman. 1985. Freshwater Fishes of Canada. Fisheries Research Board of Canada. page 175. ISBN 0-660-10239-0.)

Reproduction
Chinook salmon may spend between one to eight years in the ocean before returning to their home rivers to spawn, though the average is three to four years. Chinook prefer larger and deeper water to spawn in than other species of salmon and can be found on the spawning redds (nests) from September through to December. Fry and parr (young fish) usually stay in freshwater from twelve to eighteen months before travelling downstream to estuaries, where they remain as smolts for several months.

Range
Chinook salmon range from San Francisco Bay in California to north of the Bering Strait in Alaska, and the arctic waters of Canada and Russia (the Chukchi Sea ), including the entire Pacific coast in between. Populations occur in Asia as far south as the islands of Japan. In Russia, they are found in Kamchatka and the Kuril Islands.

Fresh water populations have also been introduced into the Great Lakes of North America. The most significant spawning runs are in the Columbia River, Rogue River, and Puget Sound. Within this range there are probably more than 1,000 spawning populations, yet the species is the least abundant salmon in North America.

The species has also established itself in the waters of the Patagonia in South America, where escaped hatchery fish have colonized rivers and established stable spawning runs. The species was introduced into New Zealand waters at the end of the nineteenth century, where it flourished. It has established spawning runs in the Hurunui, Waimakariri, Rangatata and particularly the Rakaia rivers. While other salmon were introduced into New Zealand, only Chinook (or Quinant as it is known locally in NZ) has established important pelagic runs.

The Yukon River has the longest freshwater migration route of any salmon, over 3,000 kilometers from its mouth in the Bering Sea to spawning grounds upstream of Whitehorse, Yukon. A fish ladder has been constructed around the Schwatka Lake hydroelectric dam in Whitehorse to allow the passage of Chinook salmon.

Ecology
Chinook salmon need five things to survive:

food,
spawning habitat,
ocean habitat,
clean, oxygenated water, and
other salmon
First, salmon need to be able to have ample food resources, such as: planktonic diatoms, copepods, kelps, seaweeds, jellyfish, and starfish. As with all Salmonid species, Chinook feed on insects, amphipods, and other crustaceans while young, and primarily on other fish when older. Young salmon feed in streambeds for a short period of time until they are strong enough to journey out into the ocean and acquire more food. Chinook salmon are divided into two types of juveniles, ocean type and river type. Ocean type chinook migrate to salt water in the first year of their life. Stream type spend one full year in fresh water before migrating to the ocean. Once they spend a couple of years in the ocean, adult salmon grow large enough to escape most predators and return to their original streambeds to mate. Chinook salmon can have an extended life history with some fish spending from one to five years in the ocean for up to a total age of eight years. More northernly populations tend to have older life histories.

Second, in order for salmon to be able to spawn, they must have a healthy habitat that is sheltered by eelgrass and other seaweeds. These sea plants camouflage eggs so that they are protected from predators. Also, they help shelter infant salmon so that they have the chance to eat and grow before making the journey to the ocean to join other juveniles.

Third, with regards to ocean habitat, it is essential that anadromous (freshwater-breeding) salmon migrate from stream beds to the oceans and have the ability to grow into adult fish. This is because these adult fish acquire the strength that is needed to travel back upstream, escape predators, and reproduce before dying. In fact, in his book King of Fish, David Montgomery writes that, "The reserves of fish at sea are important to restocking rivers disturbed by natural catastrophes". Thus, it is vitally important that fish are able to reach the oceans (without man-made obstructions like dams) so that they can grow into healthy adult fish that will further populate the species.

Fourth, it is important that the bodies of water are clean and oxygenated. One sign of high productivity/growth rate in the oceans are the levels of algae. Increased levels of algae lead to higher levels of carbon dioxide in the water which is transferred into living organisms, fostering growth of underwater plants and small organisms, which salmon eat (Klinger). Also, algae can contribute in filtering the water from high levels of toxins and pollutants. Thus, it is essential that algaes and other water filtering agents are not destroyed in the oceans because they contribute to the overall well-being of the ocean food chain.

Finally, salmon need other salmon to survive so that they can reproduce and pass on their genes in the wild. With some populations being endangered, it is important that precautions are taken to ensure that salmon are not being overfished and that habitat is being protected including appropriate management of hydro-electric and irrigation projects. If there are too few fish left because of harmful fishing and land management practices, it makes it more difficult for salmon to regenerate a more abundant population that will continue into the future.

When one of these five variables is destroyed or unserviceable, it leads to a decline in salmon stock. One Seattle Times article states, "Pacific salmon have disappeared from 40 percent of their historic range outside Alaska," and concludes that it is imperative that people realize the needs of salmon and try not to contribute to destructive practices that harm salmon runs (Cameron).

Some populations of chinook salmon are listed under the U.S. Endangered Species Act as either threatened or endangered. Fisheries in the U.S. and Canada are limited by impacts to weak and endangered salmon runs.

Miscellaneous
Chinook salmon are highly valued, despite their scarcity relative to other Pacific salmon along most of the Pacific coast.

Chinook are prized among Native American tribes for cultural and spiritual reasons. Many tribes celebrate "First Salmon Ceremonies" with the first spring Chinook harvested each year. Salmon fishing is still important economically for many tribal communities with Chinook typically being the most economically valuable species.

Chinooks are called "king salmon" (particularly in Alaska) because of their large size and because many consider them to be the best tasting of the salmon species. Those from the Copper River in Alaska are particularly known for their color, rich flavor, firm texture, and high Omega-3 oil content.

The typical lifespan of an Alaskan Chinook salmon is 4-5 years, although some Chinooks return to the fresh water one or two years earlier than their counterparts, and are referred to as "Jack" salmon. "Jack" salmon can be half the size of an adult Chinook salmon, and are usually thrown back by sportsmen but kept by commercial fishermen.

The species was described and enthusiastically eaten by the Lewis and Clark Expedition.

The Chinook salmon (under the name "king salmon") is the state fish of Alaska.

http://en.wikipedia.org/wiki/Chinook_salmon

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