Enhancing Farmer Access to Sustainable Shellfish Aquaculture Areas: An Ecosystem Approach

The project was administered by the Provincetown Center for Coastal Studies (PCCS) in collaboration with a commercial shellfish farmer (John Baldwin, Seafood Divers, Inc.), the shellfish advisory committees of Truro and Provincetown, and the Shellfish Constable/Warden of each town. Preliminary mapping of a potential subtidal ADA was conducted using ArcGIS Geographic Information System (GIS) software (Environmental Systems Research Institute, Inc., Redlands, California). Following extensive outreach, local knowledge was incorporated using an interactive process by employing the GIS software during group and individual meetings with participants and stakeholders. Maps of local waters were displayed on a computer screen or projected during larger group meetings, and areas of potentially conflicting human uses (commercial and recreational fishing, boating, etc.), local management boundaries, ideal grow-out conditions, and existing shellfish abundance were plotted based on local knowledge. The site selection process followed criteria defined by regional best management practices (BMPs) that include directives to follow state classification of waters for shellfish propagation based on water quality, minimize potential conflict with other human uses (e.g. boat traffic, fishing), and ensure that sites are free of submerged underwater vegetation. State management efforts protecting submerged aquatic vegetation prohibit aquaculture activities in areas of eelgrass abundance, and dictate that existing wild shellfish populations in the area must not be affected by culture operations. The above data and criteria were combined with publicly available information on eelgrass distribution and bathymetry to identify potential ADA sites for subsequent seafloor mapping and dive surveys. Sites deemed inappropriate for subtidal aquaculture were eliminated from further consideration. A 50-acre site straddling town boundaries was chosen due to the projected ease of joint management of two contiguous ADAs (Figure 1).

Acoustic backscatter data from an interferometric sonar system were used to classify seafloor habitat type. Sonar surveys were conducted from mid-July to mid-August 2010 as part of a nearshore seafloor mapping project in northeastern Cape Cod Bay, during which the utility of this technology to detect eelgrass beds and fine-scale features such as sand ripples was successfully demonstrated. Underwater surveys were conducted at the potential ADA site on 28 and 29 November 2010, working from a 35 ft commercial fishing and dive support vessel (F/V Chase). Divers were experienced in underwater harvest and culture of shellfish and had prior environmental survey experience. At each station, an underwater transect was surveyed and photographs were taken using a handheld digital underwater camera to qualitatively assess bottom habitat type and check for eelgrass presence. Species composition and abundance of shellfish and other benthic organisms were recorded within 1 meter quadrats at each station.

The smooth, sandy bottom observed was deemed ideal for subtidal seafloor culture methods for surf clams and other species according to the local knowledge gathered during the outreach component of this project and the experience of project participants. Evidence of a relatively dynamic environment in the eastern section of the site was indicated by ripples and loosely packed sand observed during underwater surveys. Information of this type is useful for planning shellfish aquaculture operations, as stock may need to be protected from sediment re-suspension. It is noteworthy that sea stars and moon snails, both of which are well-known predators of farmed shellfish, were observed during diver transects and quadrat sampling. Future aquaculture efforts in this area may need to consider predator exclusion methods to prevent losses to these predators.
Outreach to current and potential shellfish farmers was conducted by PCCS and all collaborators. The town shellfish advisory committees included commercial farmers and provided a de facto steering group during this project. Project participants presented the results of the mapping efforts to the selectmen of each town in early 2011. The selectmen of both towns voted unanimously to designate the 25-acre abutting sites in each town’s waters as an ADA, initiating the state and federal permitting and regulatory review processes, during which project participants provided technical support. In summer 2011, the ADAs were marked with buoys and a biological survey was conducted by the Massachusetts Division of Marine Fisheries (MADMF) with field support provided by project participants. MADMF approved the 50 acres for aquaculture in fall 2011. Project participants provided technical support to the shellfish committees of each town as they worked to design regulations for management of ADAs. Regulations include application criteria for prospective farmers and measures to prevent entanglements of marine animals in gear that could be employed for off-bottom shellfish culture methods. At the time of this report, draft regulations have been completed and public hearings to ratify them are scheduled for March 2012. Completion of the permit application and regulatory review process is anticipated by summer 2012.

• Figure 1. Study area and potential community subtidal aquaculture development area (ADA). Eelgrass data (1995, 2001) courtesy of the Massachusetts Office of Coastal Zone Management. The “mobile gear line” indicates a demarcation line south of which hydraulic dredges are used for commercial harvest of clams. Areas of lobster fishing were identified using local traditional knowledge.