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The chinook salmon, Oncorhynchus tshawytscha, (derived from Russian ??????), is a species of anadromous fish in the salmon family and is the family's largest member. 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, Quinnat 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. Chinook salmon are highly valued, due in part to their scarcity relative to other Pacific salmon along most of the Pacific coast.

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 range in size from 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 (4.54 to 22.7 kg), but may reach 130 pounds (59 kg). The current sport caught World Record is 97 pounds 4 ounces (44.1 kg) and was caught in May 1985 by Les Anderson in the Kenai River (Kenai, Alaska). The commercial catch world record is 126 pounds (57 kg) caught near Petersburg, Alaska in a fish trap in 1949

Chinook salmon may spend between one to five 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. After laying eggs in a redd, adult female chinook will guard the redd from 4 to 25 days before dying, while males look for additional mates. Chinook salmon eggs will hatch, depending upon water temperatures, 90 to 150 days after deposition. Eggs are deposited at a time to ensure that young salmon fry emerge during appropriate time for juvenile survival and growth. 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. 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

Chinook salmon need at least five things to survive: 1.Food, 2.Spawning habitat, 3.Ocean habitat, 4.Cold clean, oxygenated water, and 5.Other salmon

First, salmon need to be able to have these kinds of foods: 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 need adequate spawning habitat. Clean, cool, oxygenated freshwater free of sediment is essential for egg development. Chinook prefer larger sediment sizes for spawning than other pacific salmon. Riparian vegetation and woody debris help juvenile salmon by providing cover and maintaining low water temperatures.

Third, chinook need healthy ocean habitats. Juvenile salmon utilize clean, productive estuarine environments to continue growth, change physiologically to live in saltwater, and gain the energy for migration. They rely on eelgrass and other seaweeds for camouflage (protection from predators), shelter, and foraging habitat as they make their way to the open ocean. Adult fish need a rich open ocean habitat in which to acquire the strength that is needed to travel back upstream, escape predators, and reproduce before dying. 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 compromised, the affected salmon stock can decline. 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). Nine populations of chinook salmon are listed under the U.S. Endangered Species Act as either threatened or endangered.[4] Fisheries in the U.S. and Canada are limited by impacts to weak and endangered salmon runs. The fall and late-fall runs in the Central Valley population in California is a U.S. National Marine Fisheries Service Species of Concern. Species of Concern are those species about which the U.S. Government’s National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act. In April 2008 commercial fishers in both Oregon and California canceled the fishing season due to the extremely low population of chinook salmon present. The low population is being blamed on the collapse the Sacramento River run,of one of the biggest south of the Columbia. [5] In April 2009 California again canceled the season

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