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Commentaries and editorials

Science Shifting on Dam Removal

by Editors
The Oregonian, Op/Ed, November 18, 2000

Peer-reviewed article in journal Science makes strong case
that breaching dams is not best way to save salmon

No matter who winds up winning the White House, it's quite clear that neither the next president nor Congress will recommend breaching four dams on the lower Snake River anytime soon.

Those who have campaigned so vigorously to remove the Snake dams no doubt will be disappointed, and may charge that a decision to leave the dams intact is politically motivated.

But the truth is dam-breachers are losing the fight on scientific grounds.

Recently, the federal government's top salmon researchers, in an article published in the respected journal Science, an arm of the American Association for the Advancement of Science, concluded that breaching dams probably isn't an effective way to save salmon from extinction.

The article by Peter Kareiva, Michelle McClure and Michelle Marvier of the National Marine Fisheries Service lays out a solid case for leaving the dams. It argues that increasing salmon survival in the early life stages before the smolt reach the four dams -- and later in the Columbia estuary, below all eight dams in the Snake River salmon's path -- would have the greatest impact.

Under some of article's assumptions, the improvements in survival from removing dams would be too little to save Snake River spring/summer chinook. The article drives this point home by saying: "Remarkably, even if every juvenile fish that migrated downstream survived to the mouth of the Columbia," the salmon would continue to decline.

Put another way, breaching the four Snake River dams isn't likely to benefit the Snake River-bound fish as much as earlier scientific opinions suggest.

The fisheries service's monitoring studies, in which salmon are collected and tagged before they make the trip to the sea, not only give us information about where fish go, they also tell us a lot more about where and how they die.

As a result, salmon deaths that have been blamed on the dams -- statistics that tilted computer models in favor of dam breaching -- are probably caused by other factors, such as predation.

The Science article adds credibility to the fisheries service's findings. The agency is expected to complete its policy paper next month, likely recommending that the region forego dam breaching for now and take other actions to help salmon.

Those actions include restoring the rivers and streams where salmon spawn, restoring the Columbia River estuary where young salmon feed and grow before heading out to sea, reducing harvest, improving fish passage around the dams and overhauling antiquated hatchery practices.

As we learn more about what happens to the salmon in their various fresh water stages, the science is tilting away from dam breaching. Perhaps we don't know enough yet to take dam removal off the table, but the current is running against it.

Science Shifting on Dam Removal
The Oregonian, November 18, 2000

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