Maryland Department of Natural Resources

Oyster Habitat Restoration Projects

contact: Bob Conkwright (bconkwright@dnr.state.md.us)   

Oyster shell being washed overboard where it will settle on the bottom, making a new growing surface for oyter spat

     A key task in restoring the Chesapeake Bay's oyster population is finding appropriate locations to plant oyster spat and place materials on which spat will grow.  Oyster will grow on almost any stationary hard surface (substrate) and in a variety of aquatic environments.  However, a commercially sustainable oyster population requires optimal growing conditions, including appropriate growing surfaces, suitable water quality and low sedimentation rates.

      Discovery of bay bottom conditions using traditional methods requires expensive and time-consuming sampling programs or visual inspection using divers or cameras.  However, recent developments in remote-sensing technology have made mapping bay bottom characteristics more efficient and less costly.  Onboard DNR's R/V Kerhin, Maryland Geological Survey has the capability to map the bay bottom and subsurface geology using acoustic remote sensing systems.  These systems include:

  • side scan sonar for imaging bottom surface conditions;
  • acoustic seabed classification to determine sea floor sediment and habitats;
  • seismic profiling for stratigraphic analysis;
  • underwater video camera arrays for visualization of bottom conditions.

     The Coastal and Estuarine Geology program participates in several oyster restoration projects around the Chesapeake Bay, including the Poplar Island Environmental Restoration Project and the Oyster Bed Mapping Project.  This work will lead to a more thorough understanding of bay bottom conditions and how they affect the growth and health of oyster populations in tidewater Maryland.
     Information about MGS oyster restoration projects can be found at the following links.

  Oyster Restoration Projects Technology Overview  
   
   Technology Overview  
 
  • side scan imaging (for more information see EdgeTech Marine)
    The side-scan sonar system ensonifies the sediment surface as well as a thin near-surface layer and presents results that enable interpretation of the surficial characteristics of the bottom. These characteristics would include presence of oyster shells, small to large scale surface features such as sand waves, topographic breaks and items that stand above the bottom, as well as differentiation of soft muddy bottom sediments from areas composed of sandy sediments. The aerially continuous nature of the resultant data enables maps of the bottom to be readily developed.

  • seismic profiling (for more information see Knudsen Engineering, Ltd)
    The sub-bottom profiling equipment ensonifies the layers of sediments directly below the boat path thus enabling an internal view of the sediment layers that occur below the sediment water interface. These results may be used to determine internal layers of sediments that may have resulted from changes in sedimentation rates, alterations in currents and river flow characteristics, and resulting burying of bottom features including oyster bars.

  • acoustic sea floor classification (for more information see QuesterTangent)
    The acoustic sediment classification system also ensonifies the bottom directly below the vessel path, and the results can be used to classify the surficial sediments into areas with differing acoustic characteristics. The acoustic differences can be linked to such things as variations in the sediment composition related to grain size, the presence of differing populations of benthic infauna and epifauna, and the presence and density of submersed aquatic vegetation and macroalgae.
 
 


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