Chinook Salmon

The Chinook salmon is the largest of the Pacific salmon species. It features an elongated, robust body with a bluish-green back, silvery sides, and a white belly. During the ocean phase, they have dark spots on their back, dorsal fin, and both lobes of the caudal (tail) fin, along with a distinct black pigmentation along the gum line (hence the common nickname 'blackmouth'). When they return to freshwater to spawn, their coloration changes dramatically, turning dark olive-brown, reddish, or purple, and males develop a pronounced hooked jaw, known as a kype.

Native to the cold North Pacific Ocean and the coastal river systems of North America and northeastern Asia. They spend the majority of their adult lives in deep pelagic marine waters before migrating inland to spawn in large, gravel-bottomed freshwater rivers and streams.

Solitary or loosely aggregated during their ocean migration phase, becoming intensely migratory and territorial when ascending freshwater rivers to spawn. They are primarily diurnal, relying on daylight to navigate long distances upriver.

In freshwater, juveniles feed on plankton, terrestrial and aquatic insects, and small crustaceans. In the ocean, adults transition to an opportunistic carnivorous diet consisting primarily of smaller schooling fish such as herring, sardines, sand lance, and squid.

Anadromous species. Adults make extraordinary upstream migrations to spawn in gravelly riverbeds. Females use their tails to excavate a depression called a redd, where they deposit eggs while males fertilize them. The adults die shortly after spawning. Eggs hatch into alevins, develop into fry and parr, and eventually migrate downstream to the ocean as smolts.

Chinook salmon play a vital nutrient transport role in forest and river ecosystems. When returning from the ocean to spawn and die, their carcasses deposit marine-derived nitrogen, carbon, and phosphorus into freshwater environments, feeding dozens of species of mammals, birds, and insects.

Coho salmon (Oncorhynchus kisutch) is similar in appearance but is generally smaller, has white gums rather than black, and features spots predominantly on the upper lobe of the tail rather than both lobes.

Look for the characteristically large size, spots on both lobes of the caudal fin, and the diagnostic black gum line in the lower jaw.

Chinook salmon possess an incredible olfactory memory, allowing them to navigate thousands of miles across the open ocean back to the exact gravel bed where they were hatched.