October 6, 2006
From Oct. 9-16, scientists and technologists will deploy a new underwater robot to map deep portions of Oculina Bank, a unique 100 mile (160 kilometers) stretch of coral mounds off the east coast of Florida. The expedition has two main goals. The first is to map a series of coral recolonization experiments (concrete structures) deployed by the National Oceanic and Atmospheric Administration (NOAA) and academic partners over the past 10 years. Scientists are hoping to see new recruitment of corals and reef fish to the concrete structures deployed in the late 1990s, in areas where coral was extensively damaged.
The second project goal is to map deep portions of the Experimental Closed Area, in waters that have not been mapped before using multi-beam sonar. These unmapped areas may contain undiscovered coral patches and tilefish burrow communities, which the AUV can detect and map for the first time.
During the mission, members of the crew will provide daily updates on the Web at http://www.uncw.edu/nurc/auv/oculina2006/. These updates will focus on the mission’s progress, including journals, imagery, and opportunities to interact with the science team.
Oculina Bank is known to local residents of the Treasure and Space Coasts as a marine reserve (Habitat Area of Particular Concern) closed to bottom fishing to protect corals, and renowned place to fish for tuna and other coastal migratory pelagic fish along the edge of the Gulf Stream. The shelf edge off Florida is also the only known place in the world where Oculina varicosa, commonly known as ivory tree coral, has formed extensive high relief pinnacles as high as 120 feet (35 m) above the surrounding bottom. Healthy Oculina mounds are as productive as shallow tropical coral reefs, and provide important habitat for reef fish populations, including several economically valuable species of snappers and groupers.
Past shrimp trawling and scallop dredging activities extensively damaged the habitat and significantly reduced live coral cover. In order to protect the corals, over 300 square miles (1000 square km) of the bank stretching from Fort Pierce to Cape Canaveral have been designated as the Oculina Habitat Area of Particular Concern (HAPC) by the South Atlantic Fishery Management Council (SAFMC). In 1994, 92 square miles (300 square km) at the southern end of the HAPC was designated an Experimental Closed Area closed to fishing for reef fish, due to regional declines in landings of valuable species such as Warsaw, Snowy, Scamp and Gag groupers.
Scientists and technologists from the NOAA Undersea Research Center at the University of North Carolina Wilmington (NURC/UNCW) have engaged in mapping the Oculina HAPC, in order to provide the SAFMC with the information needed to manage the area. Maps and explorations done using submarines and tethered robots contributed to the recent council decision to continue the Oculina Experimental Closed Area regulations indefinitely, thus protecting both fish and corals.
Most seafloor mapping surveys are conducted using sonars (single-beam fathometers or newer multi-beam swath mapping systems) mounted on surface vessels. Although multi-beam sonar technology provides the best available bottom map, it is limited in resolution by depth and cannot map coral beds accurately in the deeper parts of the Oculina HAPC. “In order to monitor recovery of coral colonies that are about the size of a basketball, we need mapping systems that can detect them,” explained Andrew Shepard, chief scientist on past Oculina surveys and the upcoming 2006 cruise. “The only way to get this resolution is to put the sonar system closer to the bottom.”
With funding from the NOAA Coral Reef Conservation Program, awarded to NOAA’s Southeast Fisheries Science Center, Mr. Shepard will put the latest technologies to the test, leading a team of technicians and scientists from several partner agencies on an expedition to the Oculina Bank, using a multi-beam sonar system deployed from a newly developed untethered robot, or Autonomous Undersea Vehicle (AUV). Known as Eagle Ray, the high-tech AUV is 15 foot-long (4.6 m), weighs just under a ton in air, can dive to almost 7,000 feet (2200 m) of depth, and travel at survey speeds of over 3 knots.
On-board navigation systems allow the AUV to accurately conduct “lawn-mower” survey patterns for up to 30 hours per dive and battery charge. The multi-beam sonar system payload is capable of mapping features of less than a half-meter in size when flown about 160 feet (50 m) above the bottom. Eagle Ray AUV is owned by the National Institute for Undersea Science and Technology’s (University of Mississippi) Undersea Vehicle Technology Center (University of Southern Mississippi), and operated by UNCW. NOAA has no other assets like Eagle Ray for mapping deep sea habitats.
The AUV will be deployed from the National Aeronautics and Space Administration’s support ship M/V Liberty Star, operated by United Space Alliance out of Port Canaveral. The ship is normally engaged in space shuttle booster rocket recovery operations, and is well equipped to support robotic operations in deep water.
The SAFMC is a partner with NOAA and the University of Southern Mississippi in funding the development and initial Beta tests of the new AUV. The SAFMC supported this effort over the last three years to bring this new technology into operation and provide the new high resolution multi-beam mapping capabilities to ultimately target newly discovered deep corals in the South Atlantic. These newly discovered corals occur deeper than Oculina at depths greater than 300 meters and extend from North Carolina through the Florida Keys.
Mr. Andrew Shepard, Director, NOAA Undersea Research Center at the University of North Carolina Wilmington (sheparda@uncw.edu, 910-962-2446).