McKenzie Hatchery       

Oregon Dept. of Fish & Wildlife

    As you can see, in the photo below, the fry, has a large orange belly, which is called a yolk sac. At this stage the fry do not eat, but live on the nutrients that are contained in their yolk sacs. As the fry continues to develop, the yolk sac gradually decreases in size until it is completely absorbed.

    At this point the fish is ready to swim up out of the gravel and begin to actively feed on insects and organisms in the river, growing rapidly in size until they migrate downstream to the ocean.

    As they reach the Pacific Ocean they continue their migration North along the coasts of Washington, British Columbia, and Alaska. It is in these northern waters that they grow rapidly utilizing the abundant food sources available in the colder Gulf of Alaska.

RETURN TO FRESH WATER AND SPAWNING
    Spring Chinook return to fresh water at the age from 3-5 years old. As these adult salmon return to fresh water, and their native streams, their bodies begin to change in preparation for reproduction.

    The 4200+ eggs in each female begin to develop and mature. The males testes begin to develop to provide the sperm necessary to fertilize the eggs. The males appearance also changes as their snouts grow and develop prominent teeth to use as a defense against other males.

    The Spring Chinook, as their name implies, re-enter fresh water in the Spring and retrace their migration routes back to the rivers and streams where they spent their first years of life. They reach the McKenzie River in mid-May of each year, and hold in the deep pools until they are ready to spawn in September.

    After spawning, the adult fish die, their carcasses decomposing and providing nutrients to the river systems which is then utilized by the fingerlings as they emerge from the gravel the following January.