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Salmon Harm by Dams Disputed by Pat McCoy Capital Press, March 9, 2007

A tracking study involving 800 hatchery juvenile spring chinook released in two groups above and below the four Snake River dams found no difference in survival rates between those who went through the dams and those who didn't.

The study released 400 smolts up the Yakima River below the dams, and the same number of juveniles were released into a tributary of the Snake River above the dams. Both were tracked out into the ocean.

About 80 fish released above the dams, and the same number released below were found in Willapa Bay, Wash.

Another 200 fish were transported down river in barges and released below Bonneville Dam. Again, about 80 from this group were detected in Willapa Bay.

The study was conducted by Dr. David Welch, a Canadian researcher working under contract to the Bonneville Power Administration.

Information about the study was released by James L. Buchal, an attorney and author of "The Great Salmon Hoax," who called the study result "yet another nail in the coffin of the hypothesis that migration through four additional dams imposes significant incremental mortality on juvenile migrants."

"No study is perfect," Buchal said. "The Snake River fish were a different genetic stock than the Yakima fish, an issue that confounds all upriver-downriver determinations from different basins, but Yakima fish have enjoyed strikingly higher adult returns recently, a fact dam opponents have blamed on Snake River dam passage for the upstream stocks.

"This study provides good evidence that whatever advantage the Yakima fish have been enjoying, it isn't something that has been happening in their near-ocean life stage," the attorney said. "Dam opponents have speculated that the Snake River fish suffer delayed mortality from dam passage. As Dr. Welch confirmed, this data does not support the concept of delayed mortality."

Buchal quotes Welch as saying, "poor Snake River survival occurs somewhere later in the ocean life history, and that differential effects of the ocean have been confounded with the operation of the hydrosystem."