Coho
COHO SALMON
The Coquille River Basin has historically supported a large and healthy wild population of coho salmon.
An estimated 120,000 salmon were taken in the river commercial fishery in 1883 and a major of them were likely coho. According to a 1956 report by the Fish Commission of Oregon to the Army Corps of Engineers, a commercial river gillnet fishery took about 100,000 pounds of coho salmon annually and in earlier years the production was considerably larger.
The Oregon Department of Fish and Wildlife has no accurate method to determine the historical levels of coho salmon in the Coquille River Basin. Assuming an average size of ten pounds per fish, the historical run of wild coho salmon in the Coquille River may have been larger than 70,000 fish per year in the pre-1920 period, based on gillnet landing data.
In the 1980s the recreational catch of coho salmon on the Coquille River was relatively low and varied from year to year. Of the total coho salmon each year on the Coquille River most are caught in the river’s main stem and bay.
The population of coho salmon in the Coquille River basin in now dangerously low. Coho salmon stocks were affected by the gillnet fishery until 1950, the use of splash dams, and by poaching practices since the early 1950’s. However, coho salmon may not have been as severely affected as chinook salmon were by splash dams because coho salmon use smaller tributary streams for spawning and rearing out of the main stem rivers.
Currently, the population size of the coho salmon is affected by annual variations in freshwater and ocean conditions, habitat quality and harvest regulations. The quality of the habitat varies from poor to excellent depending on land-use patterns. Clean-out operations over the last 20 years have also severely affected the winter habitat essential to coho salmon production.
Factors such as summer stream flow, temperature, amount of cover, industrial and municipal wastes, and water withdrawal have all influenced the natural production of coho salmon in the Coquille River.
Spawning occurs throughout the Coquille River basin from November through February depending on water flow. The peak spawning period normally occurs from late December through mid January. In years with low rainfall, fish will spawn into late February.
Hatchery coho have been released into the Coquille system since 1918. In addition Coquille stocks of coho, other stocks have released into the river system. A total of 6.5 million Columbia River coho reared at the Coos River Hatchery were released into the Coquille River between 1908 and 1958.