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Habitat Mapping to Assess Health of Oyster Fishery in Apalachicola Bay, Florida
Apalachicola Bay lies in the heart of Florida's "Forgotten Coast," midway between Tallahassee and Panama City. The area is in transition, and the bay separates barrier islands undergoing rapid development from mainland communities whose economies are still based largely on the oyster and shrimp fisheries. The bay, which is about 10 km wide by 45 km long and has an average depth of 3 m, is home to the largest oyster fishery in the State (90 percent of Florida's oysters are harvested here).
To help in assessing the health of this fishery, the U.S. Geological Survey (USGS), the Apalachicola National Estuarine Research Reserve, and the National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center have started a 2-year habitat-mapping program. The first phase of acoustic mapping was completed by USGS Woods Hole Science Center staff during a 4-week effort in March and April. Dave Twichell led the group, Barry Irwin skippered the research vessel Rafael, Chuck Worley and Emile Bergeron provided technical support, Brian Andrews processed the data, Bill Danforth completed software improvements that were enthusiastically endorsed by Brian, and Dave Nichols and Jane Denny worked behind the scenes to ensure a successful field program. Shallow-water mapping is a challenge, and the seemingly unending chain of fronts that pushed through northern Florida during the survey period brought wind and floods that made for frequent stretches when the bay was acoustically inhospitable. Despite the harsh weather, a large part of the bay was surveyed, and the data are leading to an improved understanding of oyster-bed distribution. Oyster-bed distribution is controlled by both salinity and sea-floor geology. Oyster beds generally occur in areas where the salinity is 5 to 25 ppt, on three types of shallow bars formed by different geologic processes. Some oyster beds occupy shoals that originally formed as flood-tidal deltas shoreward of abandoned inlets. Others occupy linear shoals perpendicular to the prevailing westward currents. These shoals are asymmetric, with their steep sides facing westward, and appear to have originated as sand waves. The third and smallest type of shoal consists of circular mounds of dredged material dumped within 300 m of the intercoastal waterway, a passage through protected waters for small to midsize boats. Although dredging can be viewed with environmental disapproval, here the human engineering appears to be providing new oyster habitats! A videotaping and sampling program to be conducted in May and June is the next phase of the project, and we hope it will shed further light on oyster-bed formation.
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in this issue:
Habitat Mapping to Assess Health of Apalachicola Bay Oyster Fishery Submarine Ground-Water Discharge Along the Suwannee River Delta
Earth Day Celebration at Elementary School Department of Commerce Science and Technology Fellows Visit USGS USGS and American Ground Water Trust Expand Teacher Institute Program Youth Enrichment Service E-Team Visits USGS
USGS National Education Coordinator Visits St. Petersburg Office Kurt Rosenberger Joins the Western Coastal and Marine Geology Team  |
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U. S. Department of the Interior | U.S. Geological Survey
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