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Commentaries and editorials

Scientists Evaluate
NMFS' Extinction Analysis

Columbia Basin Bulletin, November 19, 1999

The National Marine Fisheries Service describes its
Cumulative Risk Initiative as a work in progress.

And the Independent Scientific Advisory Board agrees after its review of CRI analysis methods and results added this summer to the Anadromous Fish Appendix to the Corps of Engineers Lower Snake River Juvenile Salmon Migration feasibility study.

The CRI is, by its own description, "a network of NMFS scientists working to synthesize information and provide clear, consistent and scientifically rigorous decision support for salmonid conservation." A key goal of the CRI modeling efforts is to estimate the risk of quasi-extinction (less than one spawner per year) for known fish populations.

CRI analysis was employed this past summer as a "complement" to PATH analysis that was summarized by NMFS scientists in the draft biological appendix to the Corps study. The CRI methods and analysis of Endangered Species Act-listed Snake River salmon and steelhead species make an two-chapter addendum to the draft AFA, which was released for review in April. The document is now being revised for scheduled release as part of the draft feasibility study.

The 11-member ISAB was formed jointly by NMFS and the Northwest Power Planning Council to provide independent scientific advice on fish and wildlife recovery issues.

In its November 8 review of the CRI addendum to the AFA, the ISAB offered slim praise, saying it was "impressed with this new approach," but calling CRI's substantive results "preliminary and limited." It suggests that the CRI be taken several steps further to provide a sounder basis for decision-makers.

Given the newness of the process the ISAB said it considered its review "as much an evaluation of the future potential for this approach as it is an evaluation of the results obtained thus far."

"The CRI program of analysis shows great promise as a framework for considering a broader spectrum of management options for salmon recovery, but this promise remains to be fulfilled," the ISAB wrote.

The CRI analysis "largely corrects the most glaring shortcoming" in the draft AFA, which reported "implausibly low estimates of extinction risk. The CRI, significantly, shows quite high probabilities of extinction, if present condition continue." But CRI conclusions leave readers adrift.

"One might think that acknowledgment of the high probabilities of extinction for many of the stocks would raise the sense of urgency about the management decisions bearing on hydrosystem operations, possible dam breaching, and other interventions as well. But the continuing uncertainty about the efficacy of the respective management options seems to discourage decisiveness in the conclusions of the CRI," the ISAB wrote.

"The ISAB is not comfortable with this apparent drift toward delay of the actual decisions. We think it is important that discussions of uncertainty about effectiveness of management interventions be accompanied by thoughtful analysis of the possibility that there is no time to lose in beginning to implement management experiments while there are still enough local populations of listed stocks to work with."

The ISAB also suggests that the CRI analysis offer an "explicit synthesis of its own analysis and conclusions with those of the AFA or PATH."

"Such a synthesis definitely is needed, since the AFA and the CRI documents come to quite different conclusions on several important points, and arrive at those conclusions via different kinds of analysis.

"Because the analyses use different techniques, and operate on different subsets of data, some careful diagnosis is warranted to explain the different conclusions, and to choose between them in making actual recommendations for the eventual decisions that these documents are intended to support."

The CRI analysis does attempt to answer another of the ISAB's primary concerns about the draft Anadromous Fish Appendix (AFA) -- that PATH's analysis dealt too strictly with hydrosystem concerns and to lightly with habitat, hatchery and harvest variables in the fishes' life cycle.

"The CRI presents an application of the modeling package to consider specifically whether dam breaching alone, or habitat improvement and harvest reduction without dam breaching, are likely to reduce the extinction risk significantly."

"The tentative answer of the CRI to both questions is 'possibly yes' for fall chinook and steelhead, but it seems to be a qualified 'probably no' for spring/summer chinook."

The topic needs to be explored in more depth, and include analysis of the risk reduction potential of modifications to hatchery operations, the ISAB says.

"And, logically, the analysis should also evaluate the prospects for significantly reducing risk by the action of dam breaching AND addressing habitat and harvest and hatcheries," the ISAB wrote.

Midway through the ISAB review's executive summary the independent scientists offer a broad-brush critique.

"The new modeling package provides a clear logical framework that holds much promise. However, the actual implementation of the CRI document under review seems very preliminary, and has some deficiencies that weaken its usefulness for the pending decision.

"The ISAB recommends continued development and application of this approach, recognizing, realistically, that this will require more time and resources."

Related Pages:
Recovery and Management Options for Spring/Summer Chinook Salmon in the Columbia River Basin by Peter Kareiva & Michelle Marvier, Nature 11/3/00

Scientists Evaluate NMFS' Extinction Analysis
Columbia Basin Bulletin, November 19, 1999

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