Chum salmon
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| Oncorhynchus keta (Walbaum, 1792) |
Keta redirects here. Keta can also refer to a character from the Myst Franchise.
The Chum salmon (Oncorhynchus keta) is a species of anadromous fish in the salmon family. It is a Pacific salmon, may also be known as dog salmon or Keta salmon, and is often marketed under the name Silverbrite salmon.
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[edit] Appearance
They have an ocean coloration of silvery blue green. When adults are near spawning, they have purple blotchey streaks on their sides. Chum have no spots unlike other salmon. Spawning males typically grow an elongated snout or kype and have enlarged teeth. Some researchers speculate these characteristics are used to compete for mates.
[edit] Spawning
Most Chum Salmon spawn in small streams and intertidal zones, especially among stalks of eelgrass. Some Chum travel more than 3,200 km (2,000 miles) up the Yukon River. Chum fry migrate out to sea from March through July, almost immediately after becoming free swimmers. They spend one to three years traveling long distances in the ocean. These are the last salmon to spawn (November to January). They die about two weeks after they return to the freshwater to spawn. They utilize the lower tributaries of the watershed, tend to build redds in shallow edges of the watercourse and at the tail end of deep pools. The female lays eggs in the redd, the male sprays sperm on the eggs, and the female covers the eggs with gravel. The female can lay up to 4000 eggs.
[edit] Age
Chum can live from 3 to 7 years, and chum in Alaska mature at the age of 4 years.
[edit] Where they are found
The chum salmon is found in the north Pacific in the waters of Korea, Japan, and the Okhotsk and Bering seas (Kamchatka, Kuril Islands, Sakhalin, Khabarovsk Krai, Primorsky Krai), British Columbia in Canada, and from Alaska to Oregon in the United States. \
[edit] Sizes
Adult chum usually weigh from 4.4 to 6.6 kg, with an average length of 60 cm. The record for chum is 13 kg and 102 cm.
[edit] What they eat
Juvenile chum eat zooplankton and insects.
[edit] Commercial use and value
The chum salmon is the least commercially valuable salmon. Despite being extremely plentiful in Alaska, commercial fishers often choose not to fish for them because of their low market value. Markets developed for chum from 1984 to 1994 in Japan and northern Europe which increased demand, though. They are a traditional source of dried salmon.
[edit] Conservation
In areas other than Alaska there are few groups of healthy chum remaining. This is partially because of dams, which block the free flow of the water and the migration of the fish.
Two populations of Chum have been listed under the U.S. Endangered Species Act as threatened species. These are the Hood Canal Summer Run population and the Lower Columbia River Population.
[edit] Susceptibility to diseases
Chum are thought to be pretty resistant to whirling disease, but it is unclear.
[edit] See also
[edit] References
- Oncorhynchus keta (TSN 161976). Integrated Taxonomic Information System. Accessed on 24 January 2006.
- "Oncorhynchus keta". FishBase. Ed. Ranier Froese and Daniel Pauly. 10 2005 version. N.p.: FishBase, 2005.
- Encarta Encyclopedia 2004
- Alaska Department of Fish and Game
- National Marine Fisheries Service ESA Listings
