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Abstracts
Workgroup: Oyster Fisheries Management and Restoration
In Situ Determination of Perkinsus marinus Transmission Dynamics in Low Salinity Habitats: Implications for Disease Avoidance Management Strategies and Oyster Restoration
Principal Investigator(s):
Kennedy T. Paynter, Department of Biology, UMCP, mees@mees.umd.edu
Co-Investigator(s):
Eugene Burreson, Kimberly Reece, Lisa Ragone-Calvo, Virginia Institute of Marine Science
Funding Period: 10/1/01-9/31/03
Elucidation of P. marinus transmission dynamics requires examination of environmental parasite abundances and in situ transmission rates. With the recent advancement of molecular techniques for the detection of P. marinus and the acquisition by VIMS of a state-of-the-art real-time PCR system for DNA quantification, we have the required tools for sensitive, specific, and quantitative detection of P. marinus. We have conducted an investigation funded by ODRP, in which these molecular tools have been optimized and utilized to quantify the number of parasite cells in water samples collected at several sites within low and moderate salinity areas in both Maryland and Virginia. Concurrently we monitored infection acquisition by naÔve sentinel oysters deployed at the same sites, and oyster mortality and P. marinus prevalence in local native oyster populations.
During this current funding cycle we have developed and refined our monitoring protocols and the PCR assay. This experimental framework has successfully been established and our results to date are beginning to demonstrate linkages between infected host mortality, water column parasite abundance, and infection transmission to naÔve sentinel oysters in the James River. Although much of the data from Maryland has yet to be analyzed we anticipate lower parasite abundances since salinity at the Maryland sites are lower. As with any in situ investigation conducted in a complex system, the interannual variation of a diversity of environmental parameters can affect the strength of correlations between dependent variables and may lead to erroneous interpretations of the results. For this reason, validation of the results of the two-year study, currently in progress, will require additional years of study, especially given the nearly two year old drought the Chesapeake Bay watershed is currently experiencing. We are currently proposing to extend our present study an additional two years and to expand both temporally and spatially our current sampling regime.
IMPACTS and/or BENEFITS:
This research will contribute data important to our understanding of disease processes in the Chesapeake Bay, allowing managers to better control and manage disease problems plaguing the oyster industries of both Virginia and Maryland. Results from this research could lead directly to changes in management practices that could significantly reduce disease problems in certain areas. It will also provide data critical for oyster population/disease models being developed for oyster populations in the Chesapeake Bay.
PROJECT PUBLICATIONS:
In situ determination of Perkinsus marinus transmission dynamics. Lisa Ragone Calvo, Corinne Audemard, Kimberly Reece, Eugene Burreson, Virginia Institute of Marine Science; and Kennedy Paynter, University of Maryland. Presented at the International Conference on Shellfish Restoration, Charleston, SC.
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