COHO   (Oncorhynchus kisutch)

Blueback, Blaurücken, Silberlachs

Coho are swift, active fish.  These salmon are found in most B.C. coastal streams and in many streams from California to Alaska, but their major territory lies between Cook Inlet, halfway up the Alask coast, to the Columbia River (which borders the states of Washington and Oregon). When mature in the late fall, they weight up to 14 kg, although their average weight is between 2.7 and 5.4 kg.

Next to pinks, they probably have the most consistent life history of west coast salmon. Juvenile coho are highly adaptable and can have varied life histories. Most stay from one to two years in coastal streams before emigrating seaward as smolts. But other fry are equally at home in lakes or in coastal estuaries.

During early stages of growth, they have distinct parr markings (dark, vertical bars along each side), greenish brown backs, a white leading edge on the anal fin and an orange tint on all but the dorsal fin. As they develop into smolts, their parr marks gradually fade and their backs become green with dark spots. While a number, known as jacks, return to spawn after less than one year at sea, the majority spend two growing seasons in salt water before returning to their home stream to spawn.

While most coho tend to remain close to the coast, they have been found as far as 1,600 km from shore. Like the pink salmon, they prefer relatively warm water, often moving south in the fall and winter months. Their first ocean year is spent feeding on sand lance, herring, insects, copepods, amphipods, crab larvae and euphausids. In the second year at sea, their growth rate increases due to heavy feeding on squid, herring, sand lance and large zooplankton, taking their weight from an average 1.3 kg in March to 5.4 kg in the fall and winter when they return to their home streams to spawn.

As adults, coho have silvery sides and a metallic blue back with irregular black spots. Spawning males in fresh water may exhibit bright red on their sides, bright green on their back and head, with darker colouration on their belly. They also develop a marked hooked jaw with sharp teeth. Females change colour and develop hooked snouts, but the alteration is less spectacular.