The Chinook salmon (King Salmon) is the largest species in the Pacific Salmon family. They are native to the north Pacific Ocean and the river systems of western North America ranging from California to Alaska. The flesh of the salmon is highly valued for its dietary nutritional content, which includes high levels of important omega-3 fatty acids. The Chinook is a blue gray back with silvery sides. They have small irregular shaped spots on their backs, dorsal fins, and usually on both lobes of tail. Their gum line is black. Spawning adults take on a maroon to olive color.
Chinook salmon may spend one to eight years in the ocean (averaging from three to four years) before returning to their home rivers to spawn. Chinook spawn in larger and deeper waters than other salmon species and can be found on the spawning nests from September through to December. After laying eggs, females guard the nests from four to 25 days before dying, while males seek additional mates. Chinook salmon eggs hatch, depending upon water temperature, 90 to 150 days after deposition. Egg deposits are timed to ensure the young salmon fry emerge during an appropriate season for survival and growth. Young fish usually stay in fresh water for 12 – 18 months before traveling downstream to estuaries, where they remain as smolts for several months.
Salmon feed on planktonic diatoms, copepods, kelps, seaweeds, jellyfish and starfish. They also feed on insects, amphipods and other crustaceans while young, and primarily other fish when older. Young salmon feed in streambeds for a short period until they are strong enough to journey out into the ocean and acquire more food. Chinook juveniles divide into two types: ocean type and stream type. Ocean-type chinook migrate to saltwater in their first year. Stream-type salmon spend one full year in fresh water before migrating to the ocean. After a few years in the ocean, adult salmon, then large enough to escape most predators, return to their original streambeds to mate. Chinook salmon can have extended lifespans, where some fish spend one to five years in the ocean, reaching age eight. More northerly populations tend to have longer lives.