the different alternatives and the relative levels of impact across resource categories. For example, both the moderate and major intensity definitions for wildlife and wildlife habitat include the mention of impacts on “individuals.” Such a definition implies that the mortality of an individual organism associated with flipping of oyster bags could be interpreted as a moderate impact on the resource, which would be incompatible with the level of ecological impact.

Level of Uncertainty and Alternate Conclusions

An estimate of uncertainty, which reflects the strength of the available scientific information, gives decision makers a better understanding of the range of potential impacts for a given action alternative. Therefore, the committee assessed the data and analysis for each resource category in terms of the level of uncertainty associated with the impact assessment given in the DEIS.4 Of the eight resource categories, the committee judged that the projected impact levels for seven had moderate to high levels of uncertainty and, for many of these an equally reasonable alternate conclusion of a lower impact intensity could be reached based on the available data and information (see Table S-1). To provide an accurate analysis for the decision maker, it is important for the EIS to include estimates of level of uncertainty as part of the assessment of environmental consequences.


The DEIS employs two different baselines in assessing the impacts of the no action and action alternatives. In a typical EIS, the “no action” alternative is considered the current baseline environmental condition against which the impacts of the action alternatives are compared. However, for the DBOC Special Use Permit EIS, the no action alternative (alternative A) refers to a change from the current condition (the Special Use Permit would expire and DBOC would cease operation) and shifts to a new, future condition that is unknown. Impacts associated with action alternatives B, C, and D (10 year extension of the permit for the mariculture operation) are then compared to this projected future “baseline” (alternative A), while impacts of alternative A are compared to the better known existing conditions (i.e., with DBOC facilities and operations as described for alternative B) as the baseline. This introduces an extra level of uncertainty to the evaluation of the action alternatives and creates asymmetry in the assessments conducted for the action alternatives relative to the no action alternative. By invoking two baselines, the DEIS essentially contains two separate impact assessments, one for the no action alternative and another for the action alternatives, such that there is not a common basis for comparing the potential impacts of the no action alternative (A) with the potential impacts of the action alternatives (B, C, and D).

Suggestions for DEIS Revisions5

The committee provides the following high priority suggestions for revising the final EIS: (1) use definitions of impact intensities that demonstrably scale with their magnitude (e.g., minor, moderate,


4 Low uncertainty is assigned when the committee finds that substantial scientific evidence exists to support the conclusions reached, i.e., the evidence demonstrates a strong cause-effect relationship between Drakes Bay Oyster Company (DBOC) actions associated with an alternative and a measurable effect.

Moderate uncertainty is assigned when the committee concludes that, while there is insufficient data and information for Drakes Estero, observations from other comparable ecosystems and current scientific understanding allow logical deductions concerning a possible cause-effect relationship between DBOC actions and a measureable effect.

High uncertainty is assigned when the committee concludes that there is insufficient data and information for Drakes Estero; observations from other comparable ecosystems are not available; and scientific understanding is insufficient or controversial such that conclusions regarding a possible cause-effect between DBOC actions and a measurable effect can be made only by inference.

5 These suggestions are based on the committee’s review of the scientific foundation of the DEIS and should not be interpreted as a conclusion that the DEIS does not meet NEPA requirements.

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