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Abstracts
Workgroup: Oyster Fisheries Management and Restoration
DermoWatch: a web-based approach for managing Perkinsus marinus disease of oysters.
Principal Investigator(s):
Sammy M. Ray, Department of Marine Biology, Texas A&M University, rays@tamug.tamu.edu
Co-Investigator(s):
Thomas M. Soniat, Department of Biology, Nicholls State University, Enrique Kortright, Kortright Corporation, Thibodaux, LA
Funding Period: 9/1/99 to 10/8/03 (continuation)
Progress is continually being made on all phases of the project. The project phases include sampling oysters and disease analysis, web site improvement, and constructing a continuous monitoring station. The core sampling site is in Galveston Bay, where three leases and four public reefs are sampled monthly, and levels of Perkinsus (=Dermocystidium) marinus are determined. The field sampling and oyster analysis is kept recent, and can be seen from the home page.
New oyster sampling and disease analysis has been conducted from new locations, including the state public grounds in Louisiana and at the site of a new environmental-monitoring station in Bay Tambour near Cocodrie, Louisiana. The Louisiana Department of Wildlife and Fisheries has collected the oyster samples and the disease assays have been completed. The new Louisiana public areas (and sites) are Lake Calcasieu (West Cove, East Side), Vermillion Bay (Bayou Blanc), Sister Lake (North Bay Junop, South Bay Junop, Old Camp, Grand Pass), Barataria Bay (Hackberry Bay), Breton Sound (North Black Bay, South Black Bay, Mozambique Point, Bay Crabe, Lonesome Island, Bay Gardene, Telegraph Point), and Mississippi Sound (Three Mile Point, Cabbage Reef). The public ground sites are sampled annually, whereas the Bay Tambour site is sampled monthly. The data will be available online when a new web site is completed.
A new web site http://www.dermowatch.org, with a new look incorporating new stations, is nearing completion. The new home page includes a map of all sampled areas. Clicking on an area will give a list of sites with access to recent and historical data and a finer-scale map. The expansion of the DermoWatch program to include more sites and more participants has prompted us to develop a new data entry process. The new process is more secure and flexible since it includes individualized entry and data form generation.
The modeling to link continuous data from the monitoring station to the web site is largely complete, since it varies little from the buoy-data utility already in place http//www.blueblee.com. The modeling to produce graphs of water temperature, salinity and a time-to-critical level of disease is completed; the new web page will give a time-course prediction of weighted incidence of disease that changes with the continuously-monitored values of temperature and salinity.
A station to monitor environmental conditions at the Bay Tambour has been competed. The parameters that are being measured include wind speed and direction, solar radiation, rainfall, barometric pressure, dissolved oxygen, fluorescence (chlorophyll), turbidity, and water temperature and salinity. The station is collecting data to a data logger, but the data are not yet being transmitted to the marine lab at Cocodrie. Completion of the transmission phase has been delayed by resolvable complications due to competing transmission signals from the Bay Saint Elaine Oil Field and by delays due to tropical storm Isadore and hurricane Lilli.
IMPACTS AND BENEFITS: DermoWatch is a web-based community of scientists, managers and oyster growers. It provides recent and historical data on the occurrence and progression of Dermo disease in Texas and Louisiana. The web site calculates a time to a critical level of disease.
This is an estimate of the time that it would take the parasite to reach a critical level, assuming no change in temperature and salinity. Thus, growers and managers have a record of the present status of disease, a history of past conditions and a prediction of the future direction of disease progression.
With DermoWatch Perkinsus ceases to be an unseen killer, and growers can follow disease conditions as they relate to the mortalities they observe. The estimate of a time to critical level of disease allows an oyster grower to make an informed decision to harvest immediately, move oysters to a lower salinity area, or keep the crop in place.
PROJECT PUBLICATIONS:
Kortright, E.V., T.M. Soniat, and S.M. Ray. 2002. Web model estimates oyster parasite time-to-critical levels. Sea Technol. 43(4):43-46
Ray, S.M., T.M. Soniat, E.V. Kortright, and L. Robinson. 2002. Recent trends in levels of infection of Perkinsus marinus in oysters from Galveston Bay, Texas: results of the DermoWatch monitoring program. J. Shellfish Res. 21:375.
Soniat, T.M., E.V. Kortright, and S.M. Ray. 2002. DermoWatch: a web-based approach for monitoring the oyster parasite Perkinsus marinus (Dermocystidium marinum) J. Shellfish Res. 21:389
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