Oncorhynchus kisutch
coho salmon

Oncorhynchus kisutch, commonly known as coho salmon, are primarily found in coastal waters. Coho salmon do not range widely in the open ocean like that of many other salmon species. Oncorhynchus kisutch are also found in fresh water, during their first year and later while spawning. They are found in fresh streams of the North Pacific, ranging from Baja, California to Alaska (Wheeley, 1985).

Coho Salmon live in fresh and ocean water. In fresh water, coho like relatively slow moving water with fine gravel. In the ocean, coho tend to live closer to shores than in the open ocean. (StreamNet, 1996)

Oncorhynchus kisutch typically spend the first year of their life in fresh water. Upon moving to the ocean, growth increases dramatically. At about the third year, coho salmon reach maturity. They weigh from 6 to 12 pounds and can be up to 38 inches in length.

Oncorhynchus kisutch are deep-bodied salmon with unique color characteristics. The dorsal surface is a metallic blue while the sides are a silver color. Black spots appear on the back and upper lobe of the caudal fin. A lateral line is also present. The line is curved toward the front of the fish and straightens out as it approaches the back of the fish. While spawning, the fish's back and belly turn dark. Spawning males' sides develop a bright red line and their jaws become hooked (Clemens and Wilby, 1961).

During the first part of coho salmon's lifetimes they begin defending territories. Young coho are faster than adult coho in order to escape predators. Oncorhynchus kisutch grows up in fresh water to avoid predators, as there are more predators in the ocean. After coho have grown, they are less likely to be attacked in the ocean. Coho have a smelling sensory organ in the cartilage of their noses that allows them to retrace the path to where they were born. On their return to spawn coho do not feed. (Groot et. al., 1995)

In fresh water streams and rivers, juvenile coho salmon defend territories and compete for limited feeding sites with other fish. In order to attain these feeding sites, they may charge or chase other fish away, as growth and fitness depend on it. Coho salmon attack prey by sprinting and striking. They are able to maneuver well in order to capture prey. In fresh water, coho eat insects and smaller fish. When they move to the ocean they begin to grow rapidly due to the abundance of food. Once these fish reach the ocean their diet changes to other fish, such as herring and squid (Groot et. al., 1995).

Oncorhynchus kisutch make a good meal. Often, coho are either sold frozen or canned by commercial fisherman. Twice as many coho salmon are harvested commercially in North America than in Asia. During the late 1950's about 10 million coho salmon per year were caught. These numbers declined to 4.5 million coho per year in the 60's and have now risen to about 10.5 million coho per year. Fishing for coho is also an important sport for trollers and flyfisherman. (McNeil et. al, 1980)

There has been a serious decline of wild coho stocks in the Strait of Georgia, due to loss of habitat (from dams) and overfishing. A plan of harvest management has been developed and implemented by the Dept. of Fisheries and Oceans. (Pacific Salmon Foundation, 1995)

The scientific name Oncorhynchus kisutch was derived from the Greek roots onkos, (hook), rynchos (nose), and kisutch, the ordinary name in Siberia and Alaska. Some other common names for Oncorhynchus kisutch are coho, silver, blueback, and hook nose salmon. (StreamNet, 1996)