Chinook salmon, also known as Oncorhynchus tshawytscha, are the largest species of Pacific salmon. They have a distinctive blue-green back, silver sides, and black spots on their dorsal fins and tail. Found in the North Pacific Ocean, they migrate to freshwater rivers to spawn.

The Chinook salmon (Oncorhynchus tshawytscha) is native to the North Pacific Ocean and the river systems that drain into it. This includes regions along the coasts of North America and Asia. In North America, Chinook salmon are found from the Monterey Bay in California northwards to the Chukchi Sea in Alaska. In Asia, their range extends from the Anadyr River in Russia to Hokkaido, Japan.

Chinook salmon occupy a variety of habitats throughout their life cycle, including freshwater rivers and streams for spawning, and the open ocean as adults. They prefer cool, clean, and well-oxygenated waters for spawning, often in gravel-bottomed streams and rivers. The oceanic environment they inhabit is typically characterized by cold, nutrient-rich waters.

Chinook salmon are anadromous, meaning they migrate from the ocean to freshwater rivers to spawn. As juveniles, they inhabit freshwater environments for a period before migrating to the ocean, where they grow to adulthood. Their ecological niche includes being both predator and prey within their ecosystems. In freshwater, they feed on insects and crustaceans, while in the ocean, they primarily feed on other fish, squid, and crustaceans.