The Sockeye Salmon (Oncorhynchus nerka), also called red salmon, kokanee salmon, or blueback salmon, 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 grow up to 2 ft (9 in) in length and weigh 5–15 lb. Juveniles remain in freshwater until they are ready to migrate to the ocean, over distances of up to 1,000 mi. Their diet consists primarily of zooplankton. Sockeye salmon are semelparous, dying after they spawn. Some populations, referred to as kokanee, do not migrate to the ocean and live their entire lives in freshwater.
The sockeye salmon spends most of its life in the Pacific Ocean. However, at a certain time in the year, millions of sockeye salmon swarm into the rivers and streams off the coast of North America and Asia in an attempt to reach the place where they were born so they can spawn, an event known as the salmon run. During this run, they are prey for many different species, including salmon sharks, Steller sea lions, brown and black bears, bald eagles, wolves, river otters, pine martens, and dragonfly nymphs. Towards the end of the run, the color of the salmon's bodies start to change to red. The males also begin to develop a hooked upper jaw. At the end of the run, the salmon lay their eggs and die, providing a final burst of energy for the forest after starting the next generation.