The Oculina reefs, in depths from 250 to 300 feet, were built over the past thousand years or so by the delicate ivory tree coral Oculina varicosa, and include a series of spectacular pinnacles, mounds, and ridges that can grow up to100 feet high. Deepwater Oculina reefs are not known to exist anywhere else on the planet besides off Florida.
Fishing for shrimp and scallops has damaged a large portion of the concentrated coral areas of these reefs over the past three decades. However, the remaining healthy reefs still support dense and diverse populations of more than 70 fish species and are critical breeding grounds for commercially important populations of gag and scamp grouper as well as rock shrimp. The reefs' location directly under the Gulf Stream makes them a potentially important source of fish larvae for the entire southeast U.S. continental shelf.
Harbor Branch Oceanographic Institution scientists first discovered the deepwater Oculina reefs with the Johnson-Sea-Link submersibles in 1975. John Reed, a Harbor Branch coral expert and expedition co-principal investigator, nominated the Oculina reefs to for protection in 1981. In 1984, NOAA approved the the South Atlantic Fishery Management Council's (SAFMC) designation of 92 square miles of the Oculina reefs as a coral Habitat Area of Particular Concern (HAPC) where the use of bottom trawling, longlines, fish traps and anchoring by fishing vessels was prohibited. In 2000, the Coral HAPC was expanded to 300 square miles and now extends from Fort Pierce to Cape Canaveral. The original 92 square-mile area, now known as the Oculina Experimental Closed Area, has further restrictions including prohibition of bottom fishing for snapper and grouper species. However, surface trolling for species such as dolphin, tuna, and sailfish is still allowed in the Experimental Closed Area and the larger HAPC since it poses no threat to the reefs.
"The [SAFMC] has led the nation in managing deepwater coral ecosystems by setting up this reserve, it is now up to scientists to show if it's working," says expedition leader Andy Shepard from the National Oceanic and Atmospheric Administration's Undersea Research Center (NURC) at the University of North Carolina, Wilmington.
The Oculina expedition, funded by NOAA, will run from Oct. 12-18 on board the M/V Liberty Star, a NASA space shuttle support ship operated by United Space Alliance and normally used to retrieve spent solid rocket boosters. A second related expedition is planned for May 2006. To explore the reefs, researchers will be using NURC's Phantom SII Remotely Operated Vehicle (ROV), an undersea robot equipped with video and still cameras and a manipulator arm for gathering samples. Team members will also be filing daily dispatches from the ship at www.at-sea.org.
One of the expedition's goals is to "ground truth," or verify, a newly produced high-resolution multibeam sonar map of the region, which offers unprecedented resolution to reveal bottom features that were previously indistinguishable. The team will explore various areas using the ROV to compare observations with what appears on the map. This will allow scientists to associate certain colors and other map features with the type of habitat they indicate, such as sand bottom, coral ledges, or coral rubble, allowing more accurate assessment of the extent of the reefs and likely identification of previously unknown coral features.
"Understanding the extent of the reefs and where the most important habitats are will help researchers and managers determine those areas that need the greatest protection, and those that might require less protection, " says Reed.
Another important focus of the expedition will be to assess populations of snappers and groupers and choose sections of the reef for initial monitoring surveys to be used as benchmarks. Through comparisons over time with repeat visits scientists will be able to assess progress in the Oculina Experimental Closed Area for restoring coral cover and replenishing fish stocks. Recent expeditions have already revealed encouraging signs that fish populations in this section are slowly but surely increasing. In coming years, researchers hope to see populations of snappers and groupers recovering enough to again form large breeding aggregations in the area.
"We need to establish a statistically and scientifically sound basis to assess whether the habitat and fisheries are changing over time, and whether the reserve and enforcement are working," says Reed.
A final goal for the cruise will be to collect samples of Oculina coral whose genetics will be analyzed back on land and compared against that of Oculina found in shallow water, which is much more common. The purpose will be to determine if the deepwater version is a distinct species. This information is significant because the Washington, D.C.-based advocacy group Oceana has petitioned the federal government to include the deepwater form of Oculina under the Endangered Species Act, which would only be possible if it is in fact a genetically distinct species.
Participating in the expedition are scientists from the NOAA Undersea Research Center at the University of North Carolina at Wilmington, Harbor Branch Oceanographic Institution in Ft. Pierce, the NOAA Southeast Fisheries Science Center in Miami, the University of Oregon's Institute of Marine Biology in Charleston, the Florida Wildlife Research Institute in St. Petersburg, and the Vero Beach-based Estuarine, Coastal and Ocean Science, Inc. (ECOS), and the University of North Carolina at Chapel Hill.
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