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Abstracts
Workgroup: Oyster Fisheries Management and Restoration
Development and Management Applications of a Dual-Disease (MSX and Dermo) Model for Chesapeake Bay Oyster Populations
Principal Investigator(s):
Eileen E. Hofmann, Old Dominion University, hofmann@ccpo.odu.edu
Co-Investigator(s):
J.M. Klinck, Old Dominion University
E.N. Powell and S.E. Ford, Haskin Shellfish Research Laboratory, Rutgers University
S.J. Jordan, Paul S. Sarbanes Cooperative Oxford Laboratory
E.N. Powell and S.E. Ford, Haskin Shellfish Research Laboratory, Rutgers University
S.J. Jordan, Paul S. Sarbanes Cooperative Oxford Laboratory
Funding Period: 10/01/97-09/31/99
This project was a joint research effort between E. Hofmann and J. Klinck at Old Dominion University; E. Powell and S. Ford at the Haskin Research Laboratory, Rutgers University; and S. Jordan at the Oxford Cooperative Laboratory in Oxford, MD. This final report includes activities for the Old Dominion University component of the project. However, because of the cooperative nature of this study, the efforts of other PIs are also reflected in this report.
The primary objectives of this research are to: 1) use the H. nelsoni model to investigate the influence of biological processes and environmental variability on MSX disease prevalence and infection intensity in Eastern oyster, Crassostrea virginica, populations, and 2) understand the effect of long-term climate variations on the prevalence and intensity of MSX disease.
This project has resulted in the development of an oyster-H. nelsoni model that is physiologically-based and is structured around the transmission, proliferation and death rates of the parasite. Environmental conditions of temperature, salinity and oyster food supply provide the external forcing that results in variations in these biological rates. This model has been used to investigate the role of environmental variations versus biological processes in controlling the prevalence and intensity of MSX disease in oyster populations. The oyster-H. nelsoni model is capable of accurately simulating epizootics of MSX disease that occurred in Delaware Bay in the 1960s and those that occurred in Chesapeake Bay during the 1990s. Our research with the oyster-H. nelsoni model has also focused on developing simulations that will allow investigation of the effect of long-term climate variations on MSX disease prevalence and intensity in oyster populations in Delaware and Chesapeake Bay. The area of research has numerous implications for management of oyster populations.
Throughout this project, we have made several presentations on the oyster-H. nelsoni model at national and international scientific meetings in order to make the broader community aware of our work. These are listed below, as are the corresponding abstract publications. The oyster- H. nelsoni model and results obtained with this model are described in three manuscripts that are in press in Journal of Shellfish Research, one paper published in Science, and one paper that is submitted for a special edition of Hydrobiologia on diseases in the ocean. These are also listed below.
Our research on using models to understand environmental and biological interactions that produce observed prevalences and intensities in oyster populations was recognized nationally by an invitation for us to participate in a special symposium on "Diseases of the Ocean: A New Environmental Challenge" that was convened as part of the 1999 Annual Meeting of the American Association for the Advancement of Science (AAAS). This symposium was designed to increase awareness of the importance of disease in regulating marine populations.
Our research was further recognized by an invitation to participate in a panel discussion that was broadcast from the AAAS meeting as part of National Public Radio's Science Friday program that is hosted by Ira Flatow. The topic of the Science Friday broadcast was "Diseases in the Ocean" and E. Hofmann participated in the panel discussion as the representative of this project. Subsequently, E. Hofmann contributed to the Ocean Report, which is an outreach effort sponsored by the Pew Charitable Trusts that is broadcast daily on more than 200 radio stations. The program, which is hosted by Peter Benchley, was broadcast on 22 June 1999 and was entitled "Oyster Parasites".
E. Hofmann was invited to visit Southampton University, Southampton, NY to participate in a lecture series that is designed to make undergraduates aware of current research topics in marine science. The oyster-H. nelsoni model was the topic of the lecture that was presented, which was attended by about 60 students.
Recently the National Research Council's Committee on Climate, Ecosystems, Infectious Disease, and Human Health convened a workshop that was focused on interactions between environmental effects and diseases. We were invited to participate in this workshop and to make a presentation on our oyster disease models. We were also asked to provide input for the development of future studies to be undertaken by the NRC on disease and environmental and long-term climate interactions.
PROJECT PUBLICATIONS:
Ford, S.E., E.N. Powell, J.M. Klinck, E.E. Hofmann, Modeling the MSX Parasite in Eastern Oyster (Crassostrea virginica) Populations. I. Model Development, Implementation and Verification, Journal of Shellfish Research, 18, 475-500, 1999.
Harvell, D.C., K. Kim, J.M. Burkholder, R.R. Colwell, P.R. Epstein, J. Grimes, E.E. Hofmann, E. Lipp, A.D.M.E. Osterhaus, R. Overstreet, J.W. Porter, G.W. Smith and G. Vasta, Diseases in the Ocean: Emerging Pathogens, Climate Links, and Anthropogenic Factors, Science, 285, 1505-1510.
Hofmann, E.E., S.E. Ford, E. N. Powell and J.M. Klinck Modeling Studies of the Effect of Climate Change on MSX Disease in Eastern Oyster (Crassostrea virginica) Populations, Hydrobiologia, 460, 195-212, 2001.
Paraso, M., Ford, S.E., E.N. Powell, E.E. Hofmann, J.M. Klinck, Modeling the MSX Parasite in Eastern Oyster (Crassostrea virginica) Populations. II. Salinity Effects, Journal of Shellfish Research, 18, 501-516, 1999.
Powell, E.N., J.M. Klinck, S.E. Ford, E.E. Hofmann, S.J. Jordan, Modeling the MSX Parasite in Eastern Oyster (Crassostrea virginica) Populations. III. Regional Application and the Problem of Transmission, Journal of Shellfish Research, 18, 517-537, 1999.
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