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Project Background
The Oyster IssueThe predominant oyster species within the Chesapeake Bay, the Eastern oyster Crassostrea virginica, has suffered a steady and rapid decline due to over harvesting, habitat loss, pollution, and disease. The dwindling native oyster population, observed in the coastal waters of both Maryland and Virginia, has put a strain on the entire Chesapeake Bay ecosystem. Efforts to thwart the decline in the native population of oysters in the bay began in earnest in the 1940s. Scientists introduced the Japanese oyster Crassostrea gigas into the bay to bolster the current Eastern oyster population. Unfortunately, C. gigas did not drastically improve oyster stocks. Instead, it introduced the oyster disease MSX into the region, which further decimated the Eastern oyster population. It wasn't until the 1990's that scientists began to research the introduction of another non-native species of oyster: Crassostrea ariakensis. This Asian oyster has shown through scientific research to be able to survive in the drastic temperature and salinity ranges present in the Chesapeake Bay, and it has shown resistance to the two most prevalent oyster diseases in the region, MSX and Dermo. Most importantly to the large commercial oyster industry in the region, C. ariakensis has been observed to grow to market size in almost half the time of C. virginica. Providing Information for the Proposed Introduction of a New OysterScientists are currently studying Crassostrea ariakensis within laboratory and isolated aquaculture settings. If it is determined that the proposed introduction of this nonnative species will pose little threat to the Chesapeake Bay ecosystem, stocks of infertile triploid oyster larvae will be released into the bay in the veliger stage of development. For two to three weeks afterward, wind, tidal currents, and other oceanographic forces will distribute these larvae throughout the bay. During this time of the development stage the larvae are very susceptible to extreme temperatures and salinity levels. The Chesapeake Bay Oyster Larvae Tracker (CBOLT) gives scientists the ability to predict larvae distribution for a user-specified period of time as well as water temperature and salinity levels. This information helps users estimate and visualize location and mortality rate for a released larval stock. Oyster larvae tend to settle and proliferate in areas where oysters are already present. Researchers can use the provided historic oyster bed locations within CBOLT, in conjunction with a reverse model run, to identify the best locations to release larvae. These and other functions present in CBOLT provides scientist within the Chesapeake Bay valuable information to help them better manage and study the proposed introduction of C. ariakensis.
Chesapeake Bay Observational Data and ModelsThe ability to predict larval transport through CBOLT is largely dependent on physical oceanographic models, which are dependent on data obtained through ocean observing systems. Within the Chesapeake Bay region, the Chesapeake Bay Observing System (CBOS) provides oceanographic observations from two meterological stations and six long term moored buoys. These observations include wind speed and direction, current speed and direction, water temperature, salinity, dissolved oxygen, and ocean color. Data from these platforms and their associated sensors is collected in real-time and aggregated for retrieval by the NOAA Center for Operational Oceanographic Products and Services (CO-OPS). Observational data for the Chesapeake Bay is retrieved from CO-OPS and used as an input into the Chesapeake Bay 3-D Physical Oceanographic (C3PO) Model. This finite element hydrodynamic model was developed by the NOAA Coast Survey Development Lab. Baroclinic circulation within the bay is modeled with full salinity and temperature observations, in addition to wind forcing at the surface. The resolution of the model is greatest along the navigational channels. Higher resolution models for other portions of the bay are currently under development as part of the CBOLT project. For More InformationThe following links provide additional information on the issues surrounding the proposed introduction of Crassostrea ariakensis.
The following links provide additional information on observing systems and models within the Chesapeake Bay |
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