Jean-Michel Cousteau: Ocean Adventures
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Guide to America's National Marine Sanctuaries

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Voyage to Kure
Sharks at Risk
The Gray Whale Obstacle Course
  gray's reef

Return to the Amazon
Sea Ghosts: Belugas
Call of the Killer Whale

Loggerhead Turtles

Featured Creature
Loggerhead Turtles

Named for their large heads, loggerhead turtles are the most abundant species of sea turtle found in U.S. coastal waters. Still, it has been considered a threatened species since 1978. Loggerheads are usually reddish brown and are about 3 feet long. Over the course of their lives, they grow from tiny hatchlings, weighing about half an ounce, to adults weighing 350 pounds or more. They have strong, heavy jaws that they use to crush their food, primarily bottom-dwelling shellfish such as horseshoe crabs, clams, mussels and other invertebrates. The turtles may not start breeding until they are 20 to 30 years old or older. During the three months or so that a female loggerhead breeds, she will travel hundreds of miles to nest, lay 35 pounds or more of eggs in multiple nests, and swim back to her home foraging area -- all without eating anything significant. Learn more about this creature at the Encyclopedia of the Sanctuary (at

Gray's Reef National Marine Sanctuary

Official Web Site (at
Coastal Map of Georgia and Sanctuary (at
Encyclopedia of the Sanctuary (at

Gray's Reef was first nominated for sanctuary status by the Georgia Department of Natural Resources in 1978. It was designated a National Marine Sanctuary in 1981 by President Jimmy Carter. The sanctuary is named in recognition of Milton "Sam" Gray, a biological collector and curator who studied the area in the 1960s.

What's Underwater
Gray's Reef National Marine Sanctuary is a large near-shore live-bottom reef off the coast of Georgia. The reef is made up of rocky outcroppings 6 to10 feet tall, with sandy troughs in between. This topography results in a complex habitat of caves, burrows, troughs and overhangs -- features that serve as excellent dwellings for invertebrates, including sponges, barnacles, sea fans, hard coral, sea stars, crabs, lobsters, snails and shrimp. Also drawn to these hiding spots are fish such as black sea bass, snapper, grouper and mackerel. The fish population changes seasonally as the water temperature shifts between temperate and tropical. The reef also supports an unusual assemblage of temperate and tropical marine flora. Loggerhead sea turtles, a threatened species, use Gray's Reef year-round for foraging and resting. The reef is also part of the only known winter calving ground for the highly endangered northern right whale.


Recreational divers can visit Gray's Reef year-round, but the best diving period is from May to October. Visibility is usually 15 to 45 feet. The reef is home to loggerhead sea turtles, angelfish and coral, and it is also part of the North Atlantic right whale's breeding grounds. Sanctuary staff encourage responsible diving, in keeping with the sanctuary's mission to protect the resource. Although diving is permitted, removal of invertebrates and damage to the reef are prohibited.


Research Projects

  • Since 1995, the sanctuary has had a long-term monitoring program specifically focused on fish populations, benthic invertebrates, oceanographic conditions, sediment transport and visitor use.
  • The Loggerhead Sea Turtle Satellite Tagging Project monitors adult and juvenile loggerhead sea turtle behavior and movement in the South Atlantic Bight. Data from the project allows scientists to, among other things, explain the movements of the turtles and work on behavior models as well as to look at the interactions between sea turtles and shrimp trawlers.
  • In the field of marine archeology, efforts are under way to document the reef's existence above sea level some 15,000 years ago, when Georgia's shoreline extended more than 60 miles eastward and may have been a site of ancient human settlement. Off the coast, divers have turned up fossils of now-extinct land-dwelling animals such as ground sloths, mastodons, and early camels, horses and bison.
  • The sanctuary maintains a Gray's Reef Common Fish Identification Guide at

Challenges Facing the Sanctuary

  • Keeping the sanctuary free of marine debris and nonpoint-source pollution
  • Helping people realize that the reef and ocean resources are impacted by our watersheds and that everyone lives near, and contributes to, a watershed
  • Keeping constituents informed about and engaged in protecting and conserving the reef

Success Stories

  • Originated the effort to form an alliance among all state and federal agencies in coastal Georgia through cooperative education and outreach programs
  • Completed and maintains cooperative research projects with regional university, state, and federal partners
  • Eliminated anchoring, to protect fragile reef tops within the sanctuary
  • Instituted a joint enforcement agreement with state and federal partners
  • Originated distance-learning programming through video conferencing technology for the National Marine Sanctuary Program, reaching more than 5,500 students in 13 states to date
  • Originated ocean film festival on the East Coast that has reached nearly 10,000 viewers in three years
  • Originated radio broadcasts of ocean and sanctuary messages on commercial and public stations