Sockeye salmon also called red salmon and sometimes blueback salmon, are larger than pink salmon but average smaller in size than other Pacific Salmon species. Sockeyes measure between 18 and 31 inches (45.7-78.7 cm) in length and weigh between 4 to 15 pounds (1.8-6.8 kg). In their marine phase, sockeyes have iridescent silver sides, a white belly, and a metallic green-blue back. Due to this marine coloration, sockeyes are sometimes called blueback salmon. While they can have fine, black speckles on their backs, they lack the large spots found on other species of Pacific Salmon. The flesh of a sockeye in the marine phase is bright orange and firm. This beautiful, firm flesh with its rich flavor makes sockeyes highly prized and a culinary favorite.
When sockeyes return to their natal streams to spawn, their bodies turn bright red, and their heads become green. They are called red salmon because of this spawning coloration. In addition to changing color when they return to spawn, males develop a humped back, and hooked jaws called a kype. Breeding females are paler in color than males.
Unlike pinks, chums, and cohos that can spawn close to the mouths of small streams, sockeye salmon usually spawn in large, complex river/lake systems. Most sockeyes spawn either in streams connected to lakes or along the lakeshore in areas of upwelling. Because a sockeye requires unimpeded access to a lake to complete its life cycle, it is susceptible to habitat manipulation or degradation. Not only man but also beavers can alter a river system by building dams, effectively blocking a river or stream and denying salmon access to the lake.
The natural range for sockeyes is from the Klamath River in California and Oregon north to Point Hope in Alaska. In the western Pacific, sockeyes range from the Anadyr River in Siberia south to Hokkaido, Japan. Sockeyes are most numerous in the Fraser River system in British Columbia and the Bristol Bay system, including the Kvichak, Naknek, Ugashik, Egegik, and Nushagak rivers. Some populations of sockeyes do not migrate to the ocean but spend their entire lives in freshwater. These landlocked salmon are called kokanee salmon. Kokanees are found from Siberia to Japan on the Asian side of the Pacific and In North America from the Kenai Peninsula to the Deschutes River in Oregon. Kokanees have been widely introduced to lakes in the U.S., including the Great Lakes.
In Alaska, sockeye salmon return from the ocean to spawn from July to October. Like other Pacific Salmon species, sockeyes spawn in the streams where they were born. Some sockeyes spawn in streams not connected to lakes and others spawn near the lakeshore, but most spawn in streams attached to a lake. A female digs a nest in the stream bottom by giving several, powerful strokes of her tail. Once she finishes digging the nest, she rests while a dominant male courts her by nudging her side with his snout and then coming to rest beside her and quivering. The female then drops into the nest, and the male follows, stopping beside her. Both fish arch their bodies, open their mouths and quiver, releasing their eggs and sperm. Other males may also enter the nest and release sperm. The female will continue to dig nests until she has deposited all her eggs. She usually digs three to five nests over the course of three to five days, and she may breed with several dominant males. A female deposits between 500 to 1,000 eggs in a nest and lays a total of 2,500 to 4,300 eggs. A male sockeye may breed with several females, and both male and female sockeyes die within a few weeks after spawning.
Sockeye eggs hatch in the winter, and the young alevins remain in the gravel, gaining nutrition from their yolk sacs until spring when they emerge into the stream. At this stage of their lives, the young sockeyes are called fry and have dark, short, oval parr marks on their sides. Fry move out of the stream and into the lake where they spend one to three years in fresh water, feeding on zooplankton and small crustaceans. As they prepare to leave the lake, sockeyes lose their parr marks and turn silvery. They are now called smolts. Smolts weight only a few ounces when they enter the ocean, but they begin to grow quickly, mostly feeding on plankton, insects, and small crustaceans. A sockeye’s beautiful orange flesh comes from eating plankton and krill in the ocean.
Sockeyes spend one to four years in the ocean where they travel nearly continuously, covering as many as 2300 miles (3700 km) in one year. As it begins the return trip to its spawning stream, a mature sockeye swims even faster, covering 28 to 35 miles (45-56 km) per day during its last two months at sea. Sockeyes are prey for nearly every animal they encounter that is bigger than they are, and they are a valuable species for commercial fishermen.
Next week, I will cover the commercial and sport fishery for sockeyes as well as the status of sockeye populations and threats to their survival, including the controversial proposed Pebble Mine in Bristol Bay, Alaska.
I would love to hear your opinions and ideas about the Pebble Mine as well as about anything else related to salmon conservation or any of my other posts.
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