COHO SALMON
DID YOU KNOW?The coho salmon was introduced from Pacific waters into the Great Lakes
and is now abundant there.
SCIENTIFIC NAME:Oncorhynchus kisutch, from the Greek roots onkos (hook), rynchos (nose)
and kisutch, the common name in Siberia and Alaska.
COMMON NAMES:Silver salmon, hook nose salmon, blueback salmon, jack salmon, salmon
trout, siverside salmon and white salmon.
DESCRIPTION:The coho salmon is bluish-black with silver sides in saltwater; black
spots on the back and upper part of the caudal fin. Smaller and slimmer
than the chinook salmon; the inside of the mouth is gray or black with
white gums. Coho salmon reach up to 38.5 inches in length and weigh up
to 31 pounds; although they usually weigh between 6 to 12 pounds.
LIFE CYCLE:Spawning occurs from November to January, with the eggs hatching the
following spring. Coho fry remain in streams for over a year. Moving seaward
the following spring, most cohos return to spawn when they are three years
old. The mature male fish which return after two years are known as "jacks"
and in Oregon and Washington, the abundance of "jacks" are used
to predict the next year's three year old return.
HABITAT AND ECOLOGY:Coho salmon utilize freshwater, nearshore and offshore environments
during its lifecycles. Coho salmon spawn in the same environment as chinook
salmon; however, coho prefer lower stream velocity, shallower water and
smaller gravel. Most coho fry stay in the stream for over a year feeding
on aquatic insects, zooplankton and small fish. Adequate stream cover is
important to fry survival, as is high dissolved oxygen levels.Mortality
is especially high during freshwater lifestages, often a result of poor
forest and agricultural management practices that lead to siltation, which
may ruin spawning beds or smother the eggs. Migrating coho salmon also
face physical obstacles and high water temperatures resulting from dams,
inadequate water flows due to diversions for irrigation and impoundment
of water for power generation. Once reaching the estuaries, coho salmon
fall prey to a number of other species and may be impacted by human changes,
such as shoreline development, residential drainage and the filling of
marine wetlands. The time spent in this habitat is critical to the development
of the species and their ability to survive in the offshore environment.
RANGE:Coho salmon spawn in coastal streams from Northern Japan to the Anadyr
River in Siberia and from Monterey Bay in California and Point Hope in
Alaska. This species can also be found in the ocean from Baja, California,
to the Bering Sea in Alaska. Major U.S. spawning grounds are in Alaska,
Washington and Oregon.
ECONOMIC VALUE:The fourth most abundant salmon species, coho salmon is a culturally
and economically important resource, and an important subsistence fish.
Coho salmon is commercially fished from Northern California north to Norton
Sound in Alaska; 75% of the total U.S. catch comes from Alaska.
Revised 12/16/96
