Oncorhynchus nerka, commonly known as the Sockeye Salmon, is known for its vibrant red body during spawning season. They inhabit the Pacific Ocean but return to freshwater lakes and rivers to spawn. Sockeye Salmon are notable for their long migrations and pivotal role in nutrient cycling within their ecosystems.

Oncorhynchus nerka, commonly known as sockeye salmon, is native to the northern Pacific Ocean and its adjacent river systems. This includes parts of Asia (eastern Russia), and North America (primarily Alaska, British Columbia, and parts of the Pacific Northwest of the United States).

Sockeye salmon inhabit both freshwater and marine environments during different life stages. They are born in freshwater lakes and rivers where they spend the early part of their life. Afterward, they migrate to the open ocean where they spend several years before returning to their natal streams to spawn. The freshwater habitat is typically cold, clear, and well-oxygenated, often associated with lake or river systems that have suitable spawning gravel beds. In the marine environment, sockeye salmon inhabit the subarctic and temperate waters of the Pacific Ocean, where they adapt to the colder, saltwater conditions.

Sockeye salmon play a crucial role in their ecosystems, both as predators and prey. In freshwater, they primarily consume zooplankton and aquatic insects, while in the ocean, their diet expands to include smaller fish and crustaceans. They are a key prey species for larger predators such as orcas, bears, seals, and eagles. Additionally, their spawning migrations contribute significant nutrients to freshwater ecosystems, supporting a variety of other species.