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The population of Chinook salmon is dwindling due to human-induced and natural causes. What are the causes of endangerment?
Chinook salmon, Oncorhynchus tshawytscha,is native to the Pacific Ocean and goes by other names such as king salmon, tyee salmon, chub salmon and black salmon. Within the Chinook salmon family, there are four different classifications: Spring, Summer, Fall and Winter Chinook. These classes are determined by the season in which the adult enters fresh water. Chinook Salmon CharacteristicsThe Chinook is the largest of the salmon group with adults averaging 36 inches in length and some growing up to 56 inches. Their average weight is 10 to 50 pounds, though the larger fish can reach around 100 pounds. Chinook salmon are hatched in freshwater streams and live there for approximately one year before heading out to the Pacific Ocean. In turn, they live in the ocean for approximately three to four years before returning to the freshwater for spawning. Chinook Salmon HabitatChinook can be found on the coastal areas of the Pacific Ocean, starting around the San Francisco Bay in California and up northward through Canada and Alaska. On the eastern shores of the Pacific, Chinook can be found in Russia and south to the islands of Japan. Threats to Chinook Salmon
The building of dams and the use of water for agriculture have either dried up rivers or increased the water temperature to a point where the Chinook are no longer able to survive. These changes have altered the currents of rivers or removed sediments from the spawning grounds.
Logging, mining, urban and recreational development have caused pollution, altered the flow of rivers and changed the natural habitat for spawning salmon. In some instances, vegetation along river banks is being removed and it is causing erosion and the elimination of an important food source.
Chinook salmon continues to be a popular fish for recreational fishing and there is not always sufficient policing of catch limits. Some commercial fishing practices are not always legal or they can’t be effectively monitored when boats are out on the high seas.
Non-native species can upset the balance of nature by killing too many salmon or not killing predators that kill the salmon. Changes to their habitat can make salmon more vulnerable. For example: installing fish ladders forces a large number of salmon into a smaller space and it makes it easy for predators to find them.
Floods and droughts can negatively affect the habitat for salmon spawning because it makes river beds impassible or washes away the gravel or plants used for food. Conservation of the Chinook Salmon PopulationHatcheries are actively farming Chinook salmon on the west coast of the U.S. and Canada. In 1967, Chinook salmon were introduced in Lake Michigan and Lake Huron. This program was successful and Chinook were added to the other Great Lakes. Chinook was introduced in New Zealand in the early 1900’s and spawning runs were established in seven rivers. Conservation authorities and fisheries are restoring the salmon’s natural habitat by rerouting spawning runs around dams, adding vegetation and gravel to spawning beds, and improving water quality. A list of endangered Chinook salmon “families” is available from the NOAA Office of Protective Services.
The copyright of the article Pacific Chinook Salmon in Freshwater Fish is owned by Douglas DuHamel. Permission to republish Pacific Chinook Salmon in print or online must be granted by the author in writing.
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