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Salmon-steelhead Researchers Study
the Many Angles of Barged vs. In-river

by Columbia Basin Bulletin
Chinook Observer, January 3, 2008

COLUMBIA RIVER - The much debated strategy of transporting migrating fish downstream through the Columbia/Snake river federal dams continues to be studied from numerous angles via the U.S. Army Corps of Engineers' Anadromous Fish Evaluation Program (AFEP).

Can the transportation system be more tailored to help spawned out steelhead kelt move downriver? Will barging juvenile salmon and steelhead closer to the ocean improve their odds of returning as adults? Are changes needed within the barges to reduce disease transmission and other stressors? Does the delayed mortality effect, which some attribute to barge travel, need continued scrutiny?

All were questions probed via AFEP research that was discussed during the Corps' annual review in December in Walla Walla, as were many other questions regarding fish passage and survival in the hydro system.

For the second year in a row NOAA Fisheries Service tested the theory that barging juvenile salmon and steelhead near Astoria at the Columbia's mouth might produce better smolt-to-adult returns than releasing them at the traditional location 215 kilometers upstream near Bonneville Dam. The jury is still out.

"It looks like its providing some benefits so far," NOAA's Bill Muir said during a presentation at the AFEP conference.

Preliminary results show that the SARs for yearling Chinook captured and PIT tagged in 2006 at the lower Snake River's Lower Granite Dam and released at Astoria were nearly double that of the upriver barge releases - 0.11 percent compared to 0.06. The returns included only "jacks." Older fish from the 2006 releases will return in future years.

Steelhead released as part of the same study in 2006 returned at almost the same rate whether released at Skamania or Astoria.

In 2007, 27,766 yearling Chinook and 53,941 steelhead were released over five weekends in May. Researchers released 17,381 tagged Chinook at Skamania near Bonneville, while 11,350 yearling fish were released from barges at Astoria. A total of 31,182 steelhead were freed at Skamania and 22,759 at Astoria.

Getting little fish past hungry birds

One of the potential benefits of the lower river releases is that the fish are ferried past East Sand Island near Chinook, where the world's largest colonies of Caspian terns and double-crested cormorants reside. Preliminary results from a separate research project estimates that the two bird species combined consumed approximately 15 million juvenile salmonids, about 12 percent of the estimated number of smolts that survived to the estuary last year. Studies have shown steelhead to be particularly vulnerable to the avian predators.

The NOAA study's preliminary results indicate the lower river releases might help. In 2006, 13.8 percent of the tags from steelhead released at Skamania turned up at East Sand, as compared to 1.7 percent for the Astoria releases. The 2006 Chinook releases saw similar results, though fewer fish were taken by the birds. Tags from 3.0 percent of the Skamania releases and 0.4 percent of the Astoria releases were detected.

The ratios were similar for 2007's releases.

Another presentation focused on the results of a three-year University of Idaho examination of steelhead kelt downstream migration behaviors. It included transportation tests to evaluate whether barging can increase the number of steelhead repeat spawners. The research was led by Matthew Keefer.

Researchers say that facilitating up and downstream passage of the kelt could return, potentially hundreds of additional repeat spawners to the Snake River and, perhaps, thousands to the Columbia.

The PIT and/or radio tag monitoring of 11,769 steelhead kelt collected in 2001-2004 at John Day, McNary and Lower Granite dams showed that kelt in good physical condition returned at higher rates that poor-condition fish, and that females were at least two to four times more likely to return as repeat spawners. Kelt of wild origin, and smaller kelt, returned to spawn at higher rates than hatchery and larger fish.

"After accounting for kelt characteristics (e.g., sex, size, origin), the transport tests indicated kelts barged from Lower Granite Dam were 2.3 times more likely to return than in-river migrants," according to the study abstract. "No statistical return difference was detected between barged and in-river fish at John Day Dam."

Steelhead kelt from above Lower Granite had the lowest repeat performance, likely because of the distance they travel. Lower Granite is the first dam in the system and furthest from the ocean.

"Results provide an important baseline for evaluating kelt mortality mitigation projects (i.e., kelt reconditioning and transportation programs) and suggest that females and wild fish should perhaps be targeted in these efforts," the abstract says.

Health of barged fish: Not bad

A study of the prevalence of infectious diseases and the impact on delayed mortality of barged and in-river yearling Snake River Chinook salmon had preliminary results that mirrored previous studies.

The study led by Frank Loge of the University of California, Davis, indicated collectively that:

Loge defined delayed mortality as mortality that occurs after the outmigrants exit the hydro system, but that is influenced by dams and other factors in freshwater.

A 2006 study led by the U.S. Geological Survey's Matthew Mesa attempts to assess the physiological health and behavioral status of barged and run-of-river juvenile Chinook originating from Dworshak and Rapid River hatcheries in Idaho.

Tissue samples were collected from the fish before their release from the hatcheries and again at Lower Granite and Bonneville dams and at their release from barges. The samples were analyzed to determine gene "expression" levels and pathogen prevalence. The goal was to detect changes in stress levels, immune function and metabolism.

"Both groups showed a significant number of differential expressed genes at LGR relative to fish at the hatchery," according to the study abstract. That is an indication that the end condition is hatchery dependent.

Barged fish had the most significant response in all categories, Mesa said. The run-of-river (ROR) fish showed few differences, perhaps a sign of a natural culling process where only the strong survive.

"Maybe we're dealing with mostly Schwarzeneggers down at Bonneville," Mesa said.

As part of its conclusions, a study presented by Kintama Research's David Welch says that survival rates below Bonneivlle of ROR and transported spring Chinook smolts from the Snake and Yakima rivers are similar. Welch's ongoing study tracks smolt outmigration down the Columbia and follows them up the continental shelf as far as Alaska with an acoustic detection array.

"Survival of transported Snake River smolts between Bonneville and Willapa Bay was equal to or greater than that of ROR smolts, indicating transportation did not reduce survival," according to the study abstract.

The 2006 results indicate, however that survival rates (per week) were lower in the ocean than in freshwater, "so transportation may only deliver fish of a given size to the lower survival area (the ocean) sooner," according to Welch's abstract.

The 2006 analysis concludes that "The inability of transport (barging) to improve adult returns likely occurs because transport moves smolts between two environments with roughly similar rates of survival."

He suggested that additional complicated biological hypotheses involving delayed mortality due to stress from handling and transport may not be needed.

Analysis is ongoing of data collected from the array this year.

For more information about 2007's AFEP review and to view research abstracts go to (

Columbia Basin Bulletin
Salmon-steelhead Researchers Study the Many Angles of Barged vs. In-river
Chinook Observer, January 3, 2008

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