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Ecology and salmon related articles

Fish Passage Center Releases Annual Survival
Study for Columbia Basin Salmon, Steelhead

by Staff
Columbia Basin Bulletin, January 5, 2018

Steelhead in the Grande Ronde, Snake and Clearwater rivers are prized by fly fishers. (Michael Visintainer / Silver Bow Fly Shop) An annual report of smolt-to-adult salmon and steelhead survival through Snake and Columbia river dams was completed and released to the public at the end of December by the Fish Passage Center.

The report, called "Comparative Survival Study of PIT-tagged Spring/Summer/Fall Chinook, Summer Steelhead, and Sockeye, 2017 Annual Report" found that none of the passage routes for Snake River wild spring/summer chinook salmon and steelhead met smolt to adult return (SAR) objectives set by the Northwest Power and Conservation Council in its 2014 Fish and Wildlife Program.

SAR objectives set by the Council are 4 percent for average recovery with a 2 percent minimum.

The report further states that "The relative effectiveness of transportation has been observed to decline as in-river conditions and survival rates improve."

In addition, according to the report, "Early analyses indicated that salmon and steelhead that were transported downstream in the smolt transportation program had lower upstream migration success and higher stray rates."

News was not all bad. The study found that PIT-tag SARs for Mid-Columbia wild spring chinook and wild steelhead generally fell within the 2 to 6 percent range set by the Council.

"Incorporating the 2016 adult returns in this Annual Report shows that the trends seen in all but two past years of CSS monitoring continue," the report says. "The overall SARs for Upper Columbia and Snake River populations of salmon and steelhead are not meeting the 2 percent to 6 percent regional goal, while middle Columbia populations are meeting the regional SAR goals in most years."

The FPC had released the 2017 annual report as a draft in August and took comments until October 15. The final report is at

FPC's Comparative Survival Study, funded by the Bonneville Power Administration, is an annual study that looks at salmonid survival through Snake and Columbia river dams. For the first time it evaluated juvenile fish survival in the Snake River with and without the presence of the four lower dams on the river and it assessed the impact on survival if spill is increased, something that may occur by court order beginning April 3.

(See CBB, June 23, 2017, Litigants In Salmon BiOp Case Working Together To Develop Court-Ordered Spill-For-Fish Plan In 2018)

The study found that SARs for wild Snake River adult spring/summer chinook has declined four-fold since the early 1960s and since the four lower Snake River dams were built. SARs for wild chinook had fallen from 4.3 percent in the early 1960s to 1.0 percent during the period 1994 – 1999, and since the year 2000 SARs has been at 1.1 percent.

The study also determined that SARs for Snake River wild steelhead declined nearly four-fold from the 1960s from 7.2 percent (1964 to 1969) to 1.9 percent (1990 to 1999 and 2.5 percent during the 2000 to 2014 period.

Among other conclusions in the CSS final report are:

-- Snake River spring/summer chinook

The Council objective of 2 percent has been achieved in only two migration years for Snake River wild spring/summer chinook from 1994 through 2015(1999 and 2008). For all spring/summer chinook stocks, SARs were highest in 2008 and were very low in 2006, 2011, 2014 and 2015. The reintroduced and also unlisted Clearwater River chinook SAR was lower at a mean of 0.53 percent than other Snake River spring/summer chinook stocks.

The estimated overall SARs for Snake River hatchery spring and summer chinook varied by hatchery and year. In general, the two hatchery summer chinook populations had higher SARs than the hatchery spring chinook populations.

-- Snake River Steelhead

The mean SAR for wild Snake River steelhead during the period 1997 to 2014 was 1.6 percent, and exceeded the Council's 2 percent objective in eight of the 18 migration years. The mean SAR during 2006 to 2014 for the wild A-run group of steelhead (smaller than 28 inches in length) was 2.12 percent, about 32 percent higher than the wild B-run of steelhead at 1.6 percent.

Snake River hatchery steelhead had overall lower SARs (1.27 percent) than their wild counterparts. Overall SARs were higher for A-run hatchery steelhead than for B-run hatchery steelhead in the years 2008 to 2014, and SARs of Clearwater River hatchery B-run exceeded those from the Salmon River. None of the passage routes met Council objectives.

-- Snake River Sockeye Salmon

SARs of Snake River hatchery sockeye varied by year and hatchery group during smolt migration years 2009–2015. SARs for Sawtooth sockeye ranged from 0.10 percent to 1.15 percent in the years 2009 through 2015, whereas Oxbow sockeye SARs ranged from 0.39 percent to 2.26 percent (2009–2012). The 2015 SAR for Springfield Hatchery sockeye was 0.0 percent.

--Snake River Fall Chinook

The inclusion of fall chinook salmon is a work in progress, the CSS says. That's because it wasn't until 2010 that the CSS oversight committee received a request to begin their inclusion.

Working with the Nez Perce Tribe, the CSS funded PIT-tag marking in 2015. Some 40,400 subyearling fall chinook were tagged that year. In 2016, 50,000 were tagged and 60,000 were tagged this year. Although migration information existed prior to these PIT-tag releases, future survival estimates will benefit from the tagged fish.

Overall SARs to Lower Granite Dam (excluding jacks) for Snake River hatchery subyearling fall chinook were low in three of the seven years analyzed, the report says. Fall chinook overall SARs ranged from 0.12 percent to 0.56 percent for hatchery releases in 2006 and 0.0 percent to 0.3 percent in 2007. The highest SARs were observed for migration years 2008 and 2011 when SARs ranging from 0.30 percent to 1.07 percent.

SARs for 2009 were relatively low as well, with SARs ranging from 0.05 percent to 0.23 percent. For the 2010 migration year, SARs were between the low returns from 2009 and the highest returns from 2008. SARs for 2010 ranged from 0.20 percent to 0.97 percent. For migration year 2012 SARs ranged from 0.40 percent and 0.79 percent.

The study's project leader is the FPC's Michelle DeHart, but the report is compiled by the Comparative Survival Study Oversight Committee and the Fish Passage Center. Contributors include Jerry McCann, Brandon Chockley, Erin Cooper and Bobby Hsu of the FPC; Howard Schaller and Steve Haeseker are from the U.S. Fish and Wildlife Service; Robert Lessard is with the Columbia River InterTribal Fish Commission; Charlie Petrosky is from the Idaho Department of Fish and Game; Eric Tinus, Erick Van Dyke and Adam Storch are from the Oregon Department of Fish and Wildlife; and Dan Rawding is with the Washington Department of Fish and Wildlife.

Related Sites:
Report: Smolt To Adult Returns For Snake River Fish Remain Below NW Power/Conservation Council Goals by Staff, Columbia Basin Bulletin 10/13/17
Draft Annual Salmon Survival Study Considers Impacts Of Lower Snake Dam Breaching, More Spill by Staff, Columbia Basin Bulletin 10/6/17

Fish Passage Center Releases Annual Survival Study for Columbia Basin Salmon, Steelhead
Columbia Basin Bulletin, January 5, 2018

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