The run of coho salmon returning to the Columbia River this year will reach nearly 1 million fish, more than three times the size of the run in 2013.
The ocean abundance, before any fisheries, of early- and late-run Columbia coho is forecast at 964,100 adult fish, compared with a final estimate of 301,500 for the 2013 run. The forecast was released last week by the Technical Advisory Committee.
The 2003-2012 annual average return to the mouth of the Columbia, which subtracts ocean harvest and other mortality, is 434,100 fish, according to the July 2013 joint staff report produced by the Washington and Oregon departments of fish and wildlife.
The 2014 forecast includes an ocean abundance estimate of 526,600 Columbia River early-run fish and 437,500 late-run coho, compared with 190,800 and 110,700 estimates, respectively, last year.
Coho adults are typically 3-year-old fish, and return to freshwater after only one year in the ocean. The early-stock coho enter the river from mid-August to early October, peaking in early September. In the ocean, these early-stock coho tend to remain near the Oregon and southern Washington coasts, and most migrate southward from the Columbia River and are therefore referred to as Type S, said a task force news release.
The late-stock fish return from mid-September through December, with the peak occurring in mid-October. In the ocean, these coho tend to migrate north along the Washington coast and Vancouver Island, and are therefore referred to as Type N.
Columbia River coho return primarily to Oregon and Washington hatcheries downstream from Bonneville Dam, although substantial hatchery and some natural production now occurs in areas upstream of Bonneville Dam.
Historical natural coho-production areas above Bonneville Dam include the Spokane, Yakima, Wenatchee, Entiat, Methow and Snake rivers. The majority of coho currently passing Bonneville Dam are from the U.S. vs. Oregon management plan-mandated hatchery releases of lower-river coho stocks in the Yakima, Klickitat, Wenatchee and Methow rivers in Washington, the Umatilla in Oregon and Idaho’s Clearwater river, the news release said.
Fish releases outside the Klickitat are primarily intended to restore naturally producing coho to appropriate habitats above Bonneville Dam, most recently in the Snake, Yakima, Methow and Entiat rivers. Coho destined for areas above Bonneville Dam have represented an increasing percentage of the total return in response to increased releases above Bonneville Dam.