Sockeye salmon

Sockeye salmon
Conservation status
Endangered  (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Salmoniformes
Family:	Salmonidae
Genus:	Oncorhynchus
Species:	O. nerka
Binomial name
Oncorhynchus nerka (Walbaum, 1792)

Sockeye salmon (Oncorhynchus nerka), also called red salmon or blueback salmon, is an anadromous species of salmon found in the Pacific Ocean. In landlocked water bodies this species is called the Kokanee. It is the third most common Pacific salmon species, after Pink and Chum salmon. The name "sockeye" is believed to be a folk adaptation of the anglicization of sθə́qəy̓, , its name in Halkomelem, the language of the indigenous people along the lower reaches of the Fraser River.

Range and habitat

It ranges as far south as the Columbia River in the eastern Pacific (though individuals have been spotted as far south as the 10 Mile River on the Mendocino Coast of California) and northern Hokkaidō Island in Japan in the western Pacific, and as far north as Bathurst Inlet in the Canadian Arctic in the east and the Anadyr River in Siberia in the west. Landlocked populations occur in the Yukon Territory and British Columbia in Canada, and in Alaska, Washington, Oregon, California,New York, Utah, Idaho, Montana, Colorado,New Mexico, and Wyoming in the United States.

Physical description

Male and female sockeye salmon

A sockeye can be as long as 840 millimetres (33 in)and weigh 4 to 14 pounds (1.8 to 6.4 kg). It has an elongated, torpedo-shaped body, with an adipose fin, and a bluntly-pointed snout. The gill rakers are located just behind the head and are long and closely spaced. Its coloration changes as it migrates from saltwater to freshwater in preparation for spawning. In freshwater, its color is bright red with a pale green head; females may have green and yellow marks or stains. Its color in saltwater is bluish-green on top, silvery on the bottom, with uniform, shiny skin.

Reproduction

Sockeye are blue tinged with silver in color while living in the ocean. Just prior to spawning both sexes turn red with green heads and sport a dark stripe on their sides. Males develop a hump on their back and the jaws and teeth become hooked during their move from salt to fresh water.

Sockeye spawn mostly in streams having lakes in their watershed. The young fish, known as fry, spend up to three years in the freshwater lake before migrating to the ocean. Some stay in the lake and do not migrate. Migratory fish spend from one to four years in salt water, and thus are four to six years old when they return to spawn one summer (July-August). Navigation to the home river is thought to be done using the characteristic smell of the stream, and possibly the sun.

Some fish spend as long as four years in fresh water lakes before migrating. In rivers without lakes, many of the young move to the ocean soon after hatching. These salmon mature after one to four years in the ocean.

Kokanee

Some sockeye live and reproduce in lakes and are called "kokanee", a word in the Okanagan language for this kind of fish. They are much smaller than the ones that go to the ocean and are rarely over 350 millimetres (14 in) long. In Okanagan Lake and many others there are two kinds of kokanee populations - ne spawns in streams and one spawns in the lake near the shore. The word is in common usage for one of British Columbia's more popular beers, which was in turned name for the Kokanee Glacier, which gets its name from Kokanee Creek, which enters Kootenay Lake near Nelson, British Columbia (see Kokanee).

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  Male ocean phase Sockeye
• 
  Male freshwater phase Sockeye
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  Sockeye salmon caught on an Alaskan stream
• 
  Spawning Kokanee salmon in the Sawtooth Range of Idaho

Diet

Sockeye Salmon, unlike other species of Pacific Salmon feed extensively on zooplankton during both freshwater and saltwater life stages. Their many gill rakers strain the plankton from the water. This diet may be the reason for the striking hue of their flesh, as well as their very low concentration of methyl mercury. They also tend to feed on small aquatic organisms such as shrimp.

Population status

Sockeye salmon are currently listed under the U.S.Endangered Species Act by the National Marine Fisheries Service as an endangered species in the Snake River (Idaho, Oregon and Washington area) and as a threatened species in Lake Ozette, Washington. Other sockeye populations in the upper Columbia River and in Puget Sound (Washington) are not listed under the Act.

The return abundance of Fraser River sockeye in 2009 is currently estimated at 1,370,000, 13% of the pre-season forecast of 10,488,000. This represents a decline from the recent historical peak on this cycle of 23,631,000 in 1993 and the return abundance was the lowest in over 50 years. The reasons for this decline in productivity are not known at this time and remain speculative. According to a “Think Tank” of scientists assembled to review the problem, there is no evidence that this decline was due to over fishing. The overwhelming weight of evidence indicates this reduced productivity occurred after the juvenile fish began their migration to the ocean. The “Think Tank” scientists noted there was a need to increase Canadian research and action on the marine coastal environment and on climate impacts. Prime Minister Stephen Harper announced a judicial inquiry into decline of Fraser River sockeye with the appointment of the Honourable Bruce Cohen, Justice of the Supreme Court of British Columbia and identified the terms of reference.

Many prominent scientists and fisheries experts are attributing the sudden population decline of the Fraser River sockeye to open water fish farms that are located throughout the waters around the Campbell River, the Broughton Archipelago, and elsewhere (areas young salmon must swim through on their way to the open ocean). These experts contend that the salmon fry become infected with sea lice from the farming operations, with many eventually being killed.

Commerce

This species is netted commercially using seines and gillnets for fresh or frozen fillet sales and canning, especially in Bristol Bay, Alaska, site of the largest harvest of sockeye salmon, according to the Alaska Department of Fish and Game. The species is preferred for canning due to the rich orange-red flesh. More than half of the sockeye salmon caught today are sold frozen.

Fresh sockeye also tends to fetch a higher price than other salmon, as they are considered the most flavorful and flexible of the family.

When smoked, Sockeye has a stronger flavour and firmer texture than Coho salmon. Sockeye is popular for fly fishing, when it returns to freshwater to spawn and is an acrobatic and powerful fighter.

References

• "Oncorhynchus nerka". Integrated Taxonomic Information System. 30 January. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help)

Technical Reports

• Bristol Bay sockeye salmon inriver test fishing, 2004 / by Frederick W. West. Hosted by the Alaska State Publications Program.
• Hetta and Eek Lakes subsistence sockeye salmon project : 2004 annual report / by Jan M. Conitz ... et al.. Hosted byAlaska State Publications Program.

External links

• NOAA Fisheries sockeye salmon web page
• FishBase entry for Oncorhynchus nerka
• Animal Diversity Web entry for Oncorhynchus nerka
• Species Profile