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NCCOS Project

Boundary Options for a Research Area within Gray’s Reef National Marine Sanctuary, Georgia

This project began in January 2004 and was completed in May 2007

Coastal Georgia’s Gray’s Reef National Marine Sanctuary offered potential as the only site designated for scientific research on the continental shelf along the U.S. southeast coast. Along with a team of scientists, managers, and interest groups assembled to provide GRNMS leaders siting guidance, we used computer analysis to identify acceptable areas based on ledge locations, seafloor types, fishing activity, and other key criteria.

Why We Care
Gray’s Reef National Marine Sanctuary (GRNMS) is one of the largest near-shore areas representing live-bottom reefs and ledges along the U.S. southeast coast. Though heavily populated with fish and encrusting organisms, the functioning of the live-bottom reef, and the corresponding appropriate conservation measures, were poorly understood. The sanctuary’s research-area working group (RAWG) determined that these questions could only be addressed by establishing a research zone within the reef where fishing and other human activities are prohibited.

What We Did
To help RAWG evaluate potential sites quantitatively, we developed a GIS-based selection hierarchy that identified the optimal site, balancing the needs of researchers and existing users. According to the following criteria (listed in decreasing-value order), the site had to contain:

  • Many ledges and ledge types (since ledges are critical sanctuary features and subjects of the most pressing research)
  • All seafloor types in the sanctuary (to include full habitat data)
  • Areas researched previously (to leverage available data as a baseline for future research comparisons)
  • Minimal preferred bottom-fishing sites
  • Adjacent (outside) ledges, seafloor types, and previous research areas, for comparative purposes.

We used a sliding window approach to capture desired criteria and various shape configurations. To explore choice tradeoffs, we applied a scoring system. We narrowed the field of potential research boundaries using step-wise selection.

What We Found
The best siting options were clustered in the south/central portion of the sanctuary, where most ledges and previous research sites were located. Larger configurations were often most desirable because they encompassed more target variables, while allowing sufficient outside areas for comparison. These also included the home range for the greatest variety of fish. We also presented the consequences of high, moderate, and low stringency or selectivity options. Our results provided the requisite understanding through a systematic and comprehensive analysis of the boundary options and the resources they encompass.

On December 4, 2011, GRNMS designated the first area devoted to scientific research on the continental shelf of the US southeastern coast. This decision, reached after the conclusion of a formal public scoping process in 2008 and a final review and commenting period in 2010, was based on much of our analyses and the database of sanctuary resources we developed. Under the new regulation, the southern third of the sanctuary is now a research area where scientists will be able to study the impact of human activities on the sanctuary's marine resources. Fishing and diving are prohibited, but vessels are allowed to travel across the area.

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