Gray's Reef National Marine Sanctuary
Gray's Reef National Marine Sanctuary
2019 Gray's Reef Research Cruise Photos


Project Overview

Gray's Reef National Marine Sanctuary (GRNMS) is a hidden pearl located 19 miles offshore of Sapelo Island, Georgia and protects 22 square miles of rocky reefs that provide shelter for a diverse community of marine life. The reef is home to more than 200 species of fish and boasts a variety of other creatures like sea turtles, octopuses, sponges, rays and sharks that all live in the reef's nooks and crannies.

The reef's vibrant live-bottom habitat makes it a living laboratory that is just teeming with marine species, many of which we have yet to fully understand. It's a harbor for fishermen, divers and ocean stewards to visit and enjoy. A few years ago, NOAA established a scientific research area (RA) within Gray's Reef for scientists to study the sanctuary's unique underwater habitat, without effects from human actions. The RA encompasses the southern third of the sanctuary, about eight square miles. Fishing and diving are prohibited in the RA, and boats must transit through it without stopping. Scientists often set up experiments that mirror each other, one inside the RA and the other outside the RA in a different part of the sanctuary.

Kimberly Roberson, the Research Coordinator for Gray's Reef, serves as the Chief Scientist for thisyear's 12-daymission (July 29-Aug. 9). Kim ensures that the scientific staff are properly trained in planned operations and are knowledgeable about project objectives and priorities.

The expedition utilizes a large research vessel—the NOAA Ship Nancy Foster—to conduct research projects. The projects explore questions related to fish abundance and distribution, the structural habitat of Gray's Reef, invertebrate assessments, habitat mapping, algae diversity, and the microbial communities that live symbiotically with the reef's resident corals. Scientists also will survey the sanctuary for invasive lionfish and remove lionfish they find.

Each project planned for this expedition is described in more detail below.


Dr. Roldan Muñoz

Dr. Craig Aumack and Dr. Risa Cohen

Dr. Daniel Gleason

Erin Arneson



Dr. Roldan Muñoz of NOAA Fisheries and Kim Roberson of Gray's Reef National Marine Sanctuary are collecting ongoing data both inside and outside the research area (RA) in two key areas: fish abundance, diversity, and distribution; and habitat characteristics such as ledge height and width. Gray's Reef was designated as a national marine sanctuary because of its diversity of species and its abundance of marine life, so regular surveys of the sanctuary's structural and fish habitats are important components in protecting and preserving the health of the sanctuary for future generations. Some areas of the sanctuary are packed with large predators and schools of prey fishes. Others can harbor threatened sea turtles. The scientists will develop metrics to understand animal abundance and distribution. Learning more about the marine life in the sanctuary is vitally important to identifying, protecting, conserving, and enhancing the natural resources of Gray's Reef.


Dr. Daniel Gleason and students from Georgia Southern University document the abundance and diversity of sessile benthic invertebrate populations at numerous sites located within and outside the research area, using quadrats to identify and photograph the organisms. A quadrat is a large grid used for standardized counting of species. "Sessile" refers to organisms that are fixed in one place, "benthic" occurs on or near the bottom of a body of water – in this case, the ocean floor -- and "invertebrates" are animals that do not have a backbone, including sponges, corals, and algae. Obtaining knowledge such as this is critical for implementing appropriate management strategies because the fish in Gray's Reef depend on the invertebrates for habitat and food. Invertebrates like sponges and mussels filter water, gaining nutrients from the water and cleaning the water at the same time. For many fish species, coral provide a secure place for eggs and baby fish to hatch and live hidden from predators.


Dr. Craig Aumack and Dr. Risa Cohen of Georgia Southern University are collecting samples of macroalgae — algae that can be seen with the eye, such as seaweed — from Gray's Reef. Their effort is to provide data about the identities of the algae found within the sanctuary. Algae use photosynthesis and make oxygen as a byproduct. They also are vital producers in the food webs of marine ecosystems, with fishes being their primary consumers. Collecting more information about these small, but vital, creatures is critical to understanding the ecology of Gray's Reef.


Marine biologist Alicia Reigel from Louisiana State University is continuing her multi-year assessment of microbial communities living with the corals found in Gray's Reef. She is examining the roles these tiny organisms play and how they help their coral hosts survive under changing conditions. Ensuring that the many coral species within the sanctuary are healthy enough to withstand sudden hurricanes like Irma and Matthew is important for both humans and animals.


NOAA Corps Lieutenant Junior Grade (LTJG) Marybeth Head, who also serves as the Vessel Operations Coordinator of Gray's Reef National Marine Sanctuary and as the Divemaster for this expedition, is working with NOAA's National Centers for Coastal Ocean Science (NCCOS) and the experienced NOAA Ship Nancy Foster crew to produce a fine-scale habitat map for Gray's Reef. Using multi-beam sonar and other survey systems on the ship, Head and her team map and characterize Gray's Reef National Marine Sanctuary.


The Gray's Reef team is diving to document and if seen, remove lionfish in the sanctuary. Divers will bring the fish on board for scientists to take samples and measurements. Lionfish are an invasive species with no known predators in the South Atlantic, other than man. No lionfish were observed during the 2018 Nancy Foster Research Expedition.


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