Restoration Process

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Restoring oyster reefs

Restoring oyster reefs is a complex mix of science, public policy, and hard work involving many partners.


Site Sampling

  • To identify the areas that will have the greatest likelihood of success, the NOAA Chesapeake Bay Office maps areas using sonar technology. The team also uses “ground-truthing” and visual inspection techniques like bottom mapping, tonging, and SCUBA diver surveys on historic oyster bars.
  • The data acquired in these surveys are analyzed to show areas that are restorable. This information is used by ORP and other restoration partners to develop a blueprint for how restoration will proceed. View the Harris Creek Restoration Blueprint as an example.

Producing Spat-on-shell

Man pours oyster larvae into setting tank filled with oyster shellBaby oysters are produced in a choreography between the University of Maryland’s Center for Environmental Science’s Horn Point Hatchery, which produces oyster larvae, and ORP, which provides shell for the larvae to attach to. The shell and mature larvae meet in giant setting tanks on a pier in the Choptank River where, after about 48 hours, the larvae settle on the shell, metamorphosing into spat-on-shell (meaning they are permanently attached). Once the tanks of spat-on-shell have grown for a week, the spat are ready to be transferred to their final planting site.

Reef Site Prep & Planting

  • Some reefs require the application of additional hard-bottom substrate materials (mixed shell or granite) before spat-on-shell can be deployed. This is done by the Maryland Department of Natural Resources or the U.S. Army Corps of Engineers.
  • When the planting site is ready, the spat-on-shell are transported aboard a planting vessel where they are deployed overboard onto the designated reef.

Diver 225x225Reef Monitoring

  • At three- and six-year intervals, the constructed reefs are monitored by ORP and the restoration partners who sample to determine oyster density, growth, reef size, height, and other metrics.
  • Monitoring is used to adaptively manage the reefs. For example, if they are not meeting designated oyster density metrics, then they will be seeded again.

Publishing the Results

Every year the NOAA Chesapeake Bay Office provides a progress report on oyster restoration activities toward the Chesapeake Bay Watershed Agreement’s ‘Ten Tributaries by 2025’ oyster outcome. View the 2021 Report.