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Study Shows Dam Improvements Help Fishby StaffThe News Tribune, December 23, 2010 |
Improvements at all eight federal Snake and lower Columbia River dams boosted the safe migration of juvenile salmon and steelhead last year, according to a federal study.
Army Corps of Engineers officials said completion of passage improvements such as spillway weirs, also called fish slides, help speed young fish downstream past dams by keeping them near the water surface, where they naturally migrate.
For example, tests at Little Goose Dam on the Snake River found that 99.4 percent of yearling chinook, 99.8 percent of steelhead and 95.2 percent of sub-yearling chinook passed the dam safely.
"Almost all of the fish are coming through the dam safely now and we're on track to meet passage standards at all of the other projects," said Corps official Witt Anderson.
The assessment report says in-river survival of juvenile Snake River steelhead migrating to the ocean in 2009 reached its highest level in 12 years, a sign the fish are benefiting from improved surface passage.
The report describes the second year of progress by the Corps, U.S. Bureau of Reclamation and Bonneville Power Administration in implementing NOAA-Fisheries' biological opinion for the federal Columbia River power system. The so-called bi-op outlines protections for fish affected by the federal dams.
According to the assessment, the agencies in 2009 reopened nearly 265 miles of spawning and other salmon and steelhead habitat that had been blocked by impassible culverts, diversions or other obstacles. Since 2005 the agencies have restored access to a total of 845 miles of habitat.
"Fish are returning in numbers we haven't seen in decades and to places they haven't been for decades," said Lorri Bodi of the Bonneville Power Administration.
The report also says the agencies in 2009 restored water to salmon and steelhead streams that otherwise dwindle or run dry when fish are returning to spawn.
The 190 cubic feet per second of flow restored to streams in the Columbia River Basin last year exceeds the average amount of water consumed by Portland and nearby cities, and the amount of water restored since 2005 totals more than three times the average water use of Seattle and Portland combined.
The report also says efforts to redistribute a large colony of Caspian terns in the Columbia River estuary helped reduce their predation on juvenile salmon and steelhead from about 15 million fish in 1999 to 6.4 million in 2009.
However, it says double-crested cormorant predation on the fish is a growing concern. Together cormorants and terns ate 17.5 million juvenile salmon and steelhead in 2009, about 15 percent of all those that reached the estuary.
Related Sites:
2009 FCRPS BiOp Progress Report
12/23/2010 josephbb comments:
There are multiple problems with this "study" and its findings. First of all, dam passage (are fish alive before the dam? are they alive after the dam?) is an intentionally narrow question and analysis. A comprehensive analysis tells a much darker story. For Snake River salmon, there are 8 dams that juvenile 3-5 inch fish must pass to arrive at the ocean. Does the study account for cumulative effects? Does it merely track salmon passage through each individual dam, and then start anew at the next dam? To give a real and unvarnished picture of salmon survival, it needs to track salmon and their survival from the first dam to the eighth. There is significant loss of salmon that is not detected in this one-dam-at-a-time analysis. Dam passage is stressful and salmon may (and do) die in large numbers (10-15% per dam and reservoir) on their way through the reservoir en route to the next dam. Or after arriving in the estuary. Eight dams and reservoirs MAY pass fish alive to the ocean, but so stressed or injured that they die soon after. And dam passage does nothing to address the problems of the reservoirs themselves - the warm currentless water, the predators (pike minnows for example) that thrive in these still waters.If dam passage were all that mattered, why does the current federal salmon plan (2010 Obama Administration Salmon Plan) seek legal permission/protection to kill up to 90% of the Snake River fish as they migrate to ocean? The fact is, the feds have been passing salmon through the dams at or near these levels for the last decade; nonetheless, threatened and endangered stocks are not recovering. Fisheries managers recently estimated that spring and summer chinook are expected to return to the Columbia and Snake Rivers in 2011 at roughly the same levels that they have been over the last ten years. Bumping along at the bottom, at continued risk of extinction, is not recovery, nor "trending toward recovery."
And it leaves fishermen and fishing communities in the NW, in Idaho, and across the Pacific Coast struggling to survive. Salmon means business and economic development, but the Obama Administration, like Bush before, keep muffing the job.
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