Salmons: Salmoniformes

Physical characteristics: Chinook salmon weigh 20 to 30 pounds (9 to 14 kilograms) and are about 4 feet (1.2 meters) long. The record weight is 136 pounds (62 kilograms), and that fish was 59 inches (1.5 meters) long. The body is streamlined and narrow from side to side. There are small black spots on the back and on the tail fin. In freshwater, chinook salmon are olive brown to red or purple. At sea, adults are dark greenish to blue-black on the back and silvery to white on the belly. There are small, dark spots along the back and upper sides and on the tail fin.

Geographic range: Chinook salmon live in the Arctic and northern Pacific oceans and inland in the land bordering those waters.

Habitat: Chinook salmon spawn in freshwater and migrate to sea for feeding and maturation. In lakes they may live in water as deep as 1,230 feet (375 meters).

Diet: In streams chinook salmon mainly eat insects and small crustaceans (krus-TAY-shuns), or water-dwelling animals that have jointed legs and a hard shell but no backbone. At sea they eat fishes, crustaceans, and other invertebrates.

Adult chinook salmon can migrate nearly 3,100 miles (5,000 kilometers) from the ocean upstream to spawn. (Illustration by John Megahan. Reproduced by permission.)

Behavior and reproduction: Adult chinook salmon can migrate nearly 3,100 miles (5,000 kilometers) from the ocean upstream to spawn. In December adults start to migrate from the sea, so that they reach river mouths by early spring. The female selects the spot where she will dig her nest and aggressively drives away other females competing for the same spot. When the nest is complete, the female drops into it and is joined by the dominant male. Both fish open their mouths and vibrate, and eggs and sperm are released. The female then quickly covers the eggs by moving to the upstream edge of the nest and digging small pebbles for a new nest. This process is repeated several times until the female has released all her eggs. Spent adults usually die a few days after spawning.

Chinook salmon and people: Chinook salmon are highly regarded commercial and game fishes.

Conservation status: Chinook salmon are not threatened nor endangered. ∎