|Sockeye salmon (Oncorhynchus nerka) ? also called red salmon or blueback salmon in the United States ? is an anadromous species of salmon found in the Northern Pacific Ocean and rivers discharging into it. This species is a Pacific salmon that is primarily red in hue during spawning. They can be up to 84 cm in length and weigh anywhere from 2.3 to 7 kg. A distinguishing feature of the sockeye salmon is the lack of a definite spot on the back and tail. Juveniles remain in freshwater until they are ready to migrate to the ocean, over distances of up to 1,600 km. Their diet consists primarily of zooplankton. Sockeye salmon are semelparous, dying after they spawn.
The sockeye salmon is sometimes called red or blueback salmon, due to its hue. Sockeye are blue tinged with silver in color while living in the ocean. When they return to spawning grounds, their bodies become red and their heads turn green. Sockeye can be anywhere from 60 to 84 centimeters in length and weigh from 2.3 to 7 kg. Two distinguishing features are their long, serrated gill rakers that range from 30 to 40 in number, and their lack of a spot on their tail or back.