The Bureau of Ocean Energy Management (BOEM), through its Marine Minerals Program (MMP), authorizes the use of offshore continental shelf (OCS) sand resources in shore protection and coastal restoration projects. One of the major environmental issues with these projects is the potential for dredging entrainment and mortality of federally protected sea turtles. In accordance with Section 7 of the Endangered Species Act, BOEM is required to consult with the National Oceanic and Atmospheric Administration National Marine Fisheries Services (NMFS) for these potential impacts. As a responsible steward of OCS resources, BOEM seeks to minimize adverse environmental effects related to project specific dredging operations through deliberate project planning efforts and implementation of relevant and effective mitigation measures. Historically, BOEM and federal partners have made a significant investment in improving protective measures and best management practices, principally focusing on dredging windows, the use of sea turtle deflecting dragheads, and relocation trawling. However, there has been little effort to analyze and subsequently tailor these mitigation strategies on a project specific level. BOEM and its federal partners need to develop a standardized decision support tool to assess project specific dredging entrainment risk and improve the effectiveness of mitigation planning decisions within state and federal marine mineral resource areas.
The objectives of this project are to:
- Evaluate and document entrainment risk parameters for dredging activities in the OCS, and
- Develop a geographically and temporally based decision support tool to assess project specific dredging entrainment risk and guide mitigation planning decisions within state and federal marine mineral resource areas.
A decision support tool will be developed to evaluate sea turtle entrainment risk relative to OCS dredging activities associated with the MMP. Study methods may include data compilation, literature review and syntheses, geographic information system (GIS) analyses, and coordination with stakeholders. A panel of sea turtle biologists, dredging industry representatives, US Army Corps of Engineers, NMFS, and BOEM scientists will be convened to identify critical data parameters to be considered in the development of a decision support tool. Initial parameters to be considered may include: (1) sand source geomorphology and physical dynamics, (2) sea turtle habitat type/use (i.e. foraging, migrating, reproductive, etc.), (3) dredging intensity and entrainment history, (4) borrow area bathymetry, design, and use plan, and (5) sea turtle distribution, abundance, and behavior (leveraging existing telemetry data). All critical data parameters that directly relate to sea turtle entrainment risk will be identified and weighted based on the significance of their risk contribution. Existing project specific data sets relative to each data parameter will be consolidated and built into the model and relevant external data sets will be identified and leveraged. Initial model outputs would include regional risk classifications of OCS sand sources that could be considered in project and mitigation planning. While the initial tool will be tailored to sea turtles, the framework of the decision support system could accommodate other OCS species of concern (i.e. Atlantic sturgeon).