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Commentaries and editorials

Breaching Dams Still Best for Salmon

by Jeffrey K. Fryer
The Oregonian, Op/Ed, December 4, 2000

Upon close review of the National Marine Fisheries Service study praised by the Oregonian ("Science shifting on dam removal", Nov. 18, 2000) we reach far different conclusions than those reached by both The Oregonian and the study's authors. In this study, published in Science, NMFS scientists suggested that rather than breaching the lower Snake River dams, the survival of juveniles in the tributaries could be increased sufficiently to restore Snake River salmon.

There are several problems with this conclusion. First, NMFS scientists intentionally downplayed the large wealth of evidence that delayed mortality caused by dams and reservoirs (hydrosystem) is the key factor for the decline of Snake River Salmon. The authors cite a report recently published by the Plan for Analyzing and Testing Hypotheses (PATH) but ignore one of the key PATH's conclusions: hydrosystem induced delayed mortality is the largest reason for the declines in Snake River salmon. Notably PATH represents the collaborative work of University, Tribal, State, and Federal scientists, including NMFS, not just the work of NMFS scientists alone.

In their article, NMFS scientists also failed to utilize the "upriver/downriver" comparisons analyzed by PATH. This analysis compared Snake River salmon, which migrate through 8 dams, to similar stocks of salmon in the Columbia Basin that migrate through four or fewer dams. Analyses of the data show that since these four dams were constructed, the downstream stocks have consistently out-performed the Snake River stocks. Before the four lower Snake River dams were constructed both the upstream and downstream stocks had similar patterns of productivity.

The NMFS study also ignores both endangered Snake River fall chinook and endangered sockeye salmon. Fall chinook salmon would benefit immensely by the 140 miles of potential additional spawning and rearing habitat that would be created if the lower Snake River dams were breached. And the hydrosystem alternatives proposed by NMFS to breaching-transportation and mechanical bypass systems-may well be more harmful to juvenile sockeye salmon than the current hydrosystem.

NMFS scientists are trying to direct recovery efforts towards the part of Snake River salmon life cycle that has not declined, and away from the smolt-to-adult return rate problem. The data are clear, Snake River salmon egg-to-smolt survival has not declined, but smolt-to-adult return rates have declined dramatically. Instead of fixing the problem, the authors are suggesting that recovery can occur by reducing natural mortality sufficient to triple survival rates. Salmon would not have 4,000 - 5,000 eggs if natural mortality was not large. The authors give no hint on how we could reduce natural mortality of wild salmon in pristine wilderness with excellent habitat, let alone how feasible and uncertain these actions would be.

The authors also point to the estuary and early ocean as places where survival might be improved enough for recovery. The authors again fail to explain why salmon stocks spawning downstream of the Snake River are self sufficient with present estuary and ocean conditions. The authors again also fail to suggest what actions (besides breaching the lower Snake River dams) could be taken to dramatically improve survival in the estuary for Snake River salmon, or discuss how uncertain success would be with these actions.

The authors offer a mathematical solution to the salmon problem that only works on paper. Reliable biological modeling depends on realistic input- there is no biological basis for the values the authors use in their models.

The science is still clear * the only recovery strategy that has a high probability of recovering all stocks of Snake River salmon and steelhead is the breaching of the lower Snake River dams.

Jeffrey K. Fryer, fisheries biologist for Columbia River Inter-Tribal Fish Commission.
Breaching Dams Still Best for Salmon
The Oregonian, December 4, 2000

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