Marine Estuarine Ecology and Coastal Zone Management
Wetlands and Birds (p. 57-66)
This review focused on wetlands and birds, but also incorporated comments on other sections. The committee agrees with the comments of this review related to wetlands, birds, and eelgrass overall. The review stated that given the limited available data for many of these topics, the conclusions are reasonable and generally well supported. The review found that the DEIS also does an acceptable job of presenting the limitations posed by the data, although some topics and interpretations were “either lacking support or fundamentally incorrect" (Atkins, p. 57).
With regard to birds, the review found that the DEIS reasonably describes the ecological importance of Drakes Estero and the potential disturbances due to noise and presence of small boats under alternatives B, C, and D. The review did not agree with the argument that potential invasive invertebrate fouling of eelgrass blades would reduce consumption by migratory Brant (Atkins, p. 58). It also disagreed with the DEIS on recreational clamming; while the DEIS dismissed these effects, the review found that these activities could result in extensive and long-term disturbances to the benthos.
In general, the review emphasized that the DEIS should recognize the substantial uncertainty associated with many of the conclusions, such as those regarding the impacts of mariculture on shorebird behavior, estimates of eelgrass cover, and the contribution of mariculture to the spread of non-indigenous species in the Drakes Estero ecosystem. It critiques the use of data from San Francisco Bay to address issues of eelgrass and water quality impacts because it is not a comparable embayment and provides little insight into the dynamics of Drakes Estero. The review finds that it “remains an open question entirely whether oyster filter feeding has any effect positive or negative on eelgrass” (Atkins, p. 61), The committee concurs with this review’s appraisal of these issues in the DEIS.
Bivalve Mariculture (p. 67-75)
The committee found this review overall scientifically sound and balanced with a few exceptions. The review brought up many relevant points and provided an extensive list of additional references.
The committee did not agree with the suggestion that “… there are no data to support a notion that in this system aquaculture improves water quality or habitat quality for eelgrass,” (p. 68-69) The committee agrees with the review that there is no direct evidence that oyster culture benefits eelgrass in Drakes Estero. However, as discussed in Chapter 3 under water quality, sufficient data exists on oysters, including the Pacific oyster, to suggest that oyster mariculture in Drakes Estero could increase water clarity. At the same time, there is evidence from other ecosystems for causal relationships between bivalve growth and seagrass productivity that show both positive (Peterson and Heck, 1999; Peterson and Heck, 2001a; 2001b; Carroll et al., 2008) and negative (Vinther et al., 2008) relationships. The committee concluded that the DEIS would be unbalanced if it only discussed the adverse impacts of oyster mariculture in Drakes Estero.
This review in the Atkins report is consistent with the committee’s conclusions in highlighting the risk of spreading nonindigeneous species through mariculture operations. The review of benthic fauna is consistent with the committee’s assessment of these issues.
Water Quality (p. 77-79)
This review covered the topic of chemical toxicology thoroughly, but did not include other aspects of the effects of DBOC operations on water quality that the committee regarded as important for a thorough review of the DEIS.
The review focused on the potential effects of chromated copper arsenate (CCA) leached from pressure-treated wood used by DBOC for docks and oyster cultivation racks, and presented this as the primary source of uncertainty concerning impacts of DBOC operations on water quality. The review concluded that (1) the analyses and interpretations of environmental impacts of oyster mariculture on marine water quality are reasonable and appropriate, and (2) the DEIS includes and applies the best available science on the impacts of shellfish mariculture. Water quality parameters that could be affected by DBOC operations were not discussed in the DEIS, in part because such data do not exist or are