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Ecology and salmon related articles

Upriver Returns of Fall Chinook OK,
But Coho and Steelhead Lagging

by Laura Berg
NW Fishletter, October 3, 2016

There are no targeted steelhead fisheries on the mainstem Columbia River, and water temperatures at Bonneville Dam and
elsewhere in the Columbia/Snake system of around 68 degrees and lower since mid-September are favorable for fish passage.

A big Fall Chinook is handled in the Nez Perce Tribe hatchery. The technical committee that advises Columbia River harvest managers is projecting a fall Chinook return to the river mouth of 802,200 adult fish, about 84 percent of the preseason forecast.

The 2006-2015 average return is 705,600 adult fall Chinook.

The latest forecast includes 478,200 upriver bright fall Chinook and 52,300 Bonneville pool hatchery tule Chinook.

For steelhead, the new projections aren't so good. The run is currently estimated to be about 166,100 fish to Bonneville Dam, down from an earlier prediction of 256,200 fish.

Most of the steelhead now crossing Bonneville Dam are Group B stock migrating upstream primarily to Snake River tributaries in Idaho. The return is estimated at 38,200 fish, including 5,200 wild steelhead.

There are no targeted steelhead fisheries on the mainstem Columbia River, and water temperatures at Bonneville Dam and elsewhere in the Columbia/Snake system of around 68 degrees and lower since mid-September are favorable for fish passage.

"It seems likely that these fish did not fare well out-migrating in the warm, low water last year, and likely they ended up someplace in the ocean with poor conditions" Stuart Ellis, fish biologist and Technical Advisory Committee member, told Fishletter.

"Most of the B-sized fish seem to be doing OK, although it appears the hatchery fish are doing a bit better than the wild fish," he said.

Group A steelhead, smaller than the Group B fish and migrating earlier in the season to tributaries throughout the Columbia River Basin, are also significantly lower than the preseason prediction of 230,400 fish, which is less than 50 percent of the 10-year average. The in-season forecast is for 127,900 Group A steelhead to pass Bonneville.

"Coho and tule fall Chinook seem to not be doing great this year either," Ellis said. "Coho seem to be doing a bit better than last year, but still pretty poor."

The tule Chinook are a hatchery component of the upriver fall Chinook run. They head for facilities in the Bonneville pool area, while the majority of the upriver Chinook run is destined for Hanford Reach.

About 322,600 adult coho are expected to return to the Columbia River in 2016, or about 73 percent of the 2006-2015 average of 441,400 fish.

Of those, 84,300 coho are destined for areas upstream of Bonneville Dam.

"The tules and the coho migrate maybe as far north as central British Columbia. If both groups don't do well this year, ocean conditions in this area could easily be an important factor," Ellis said.

Many Columbia River coho stocks enter the river from mid-September through December.

Meanwhile, even with the constraints imposed by low steelhead numbers--steelhead and Chinook are in the river at the same time--harvests on the more abundant fall Chinook stocks have been generally good this year for non-Indian sports and commercial fisheries and for treaty Indian harvesters.


Laura Berg
Upriver Returns of Fall Chinook OK, But Coho and Steelhead Lagging
NW Fishletter, October 3, 2016

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