The Clackamas River is a nearly 83-mile in length and is a tributary of the Willamette River in northwestern Oregon. The Clackamas originates in the cascade mountains and empties out into the Willamette river not far from Oregon City, OR.
Since the 1800’s the Clackmas river has been a premier fishing destination offering up rich runs of spring Chinook, fall Chinook, Coho salmon, winter Steelhead, Rainbow trout, Cutthroat and Whitefish.
Historically, the Clackamas River has produced large numbers of spring chinook salmon. But the wild populations declined from commercial fishing and from the inability to reach spawning grounds due to egg-taking operations and the failure of the Cazadero fish ladder. From 1907 to 1939, chinook were trapped at the Cazadero and River Mill dams to be used for hatchery brood stock. The Cazadero fish ladder failed in 1922 and was not repaired until 1939. But after the reconstruction of the fish ladder, the remnant population from the lower river seeded the upper Clackamas. More recently, the Clackamas spring chinook originate from the Willamette stock, which has been released in the basin since the late 1950s.
In 1980, the first adults began returning to the newly completed Clackamas hatchery at McIver Park. This hatchery, which is funded by PGE, the State of Oregon, the City of Portland and the National Marine Fisheries Service, currently produces about 1.7 million chinook smolts each year, of which 1.2 million go into the Clackamas River.
Spawning in the Clackamas River has been on the rise since 1980. The additional spawning is closely associated with increases in returns of adults to the Clackamas Hatchery. A majority of hatchery-produced fish return to the river after two or three years in the ocean. Two-salt fish generally weigh 9 to 15 pounds, while three-salt fish weigh 17 to 25 pounds.
Summer steelhead were first introduced to the Clackamas River in 1970. While a few fish enter the river as early as February, good numbers are not observed until mid-April. They spawn in January and February the following year. About 85 percent return after two years in the ocean (“two-salt fish”) and average 7 to 10 pounds. The other 15 percent return after either one or three years in the ocean.
In decades’ past, summer steelhead smolts were released above North Fork Dam. They returned there as adults and entered the North Fork fish ladder adult fish trap. In recent years, summer steelhead have been acclimated or stocked in the lower river which has significantly reduced the number of adults returning to the North Fork fish trap.
Fall chinook salmon were native to the Clackamas. Present-day runs are believed to be fish of the tule strain, which was developed in the hatchery. Fall chinook enter the Clackamas and spawn in August and September. All spawning is in the main river below River Mill Dam. Fall chinook have not been stocked in the Clackamas since 1971.
The Clackamas has two stocks of coho salmon. Early-run fish begin to enter the river in August, spawning in October and early November. Most of these fish, which run 5 to 10 pounds, are headed for Eagle Creek hatchery. There is good natural reproduction in lower river tributaries and in the upper Clackamas above North Fork Dam.
The late run coho are all wild fish. Most of them spawn above North Fork Dam. These fish are larger than the early run coho, averaging 8 to 12 pounds, with some up to 16 pounds. They enter the Clackamas from November through January and spawn from January to April.
There are two stocks of winter steelhead in the Clackamas. The early run is supported by hatchery releases made in Eagle Creek by the U.S. Fish and Wildlife Service at the Eagle Creek Fish Hatchery. These fish are only released below River Mill Dam so as not to interfere with the native winter steelhead that spawn mainly above North Fork Dam. Early run winter fish begin to enter the Clackamas in November with most of them spawning in tributaries below River Mill Dam in January and February. There is some natural reproduction, particularly in Clear Creek and Deep Creek.
The late run of wild steelhead tend to be slightly larger in size than the early run fish. They begin to enter the river in January, with peak numbers generally observed in March. Migration over North Fork Dam is mostly in April and May, with fish spawning from late March to mid-June. Through support by PGE, a wild brood stock program was initiated, so this stock now provides expanded fishing opportunities on the lower river.
Sea-run cutthroat trout
Sea-run cutthroat trout in the Clackamas are all wild fish. Entering the river in September and October, they average 12 to 18 inches in length and are found in the larger tributaries below River Mill Dam.