Molluscan Ecology Monitoring & Advisory

  • Monitoring the Bay:
    Monitoring the Bay:  Aaron Beaver having fun patent tonging in the Chesapeake Bay.  Missy Southworth
  • Monitoring the Bay
    Monitoring the Bay  Measuring oysters.  Missy Southworth
  • Example of an oyster reef community.
    Example of an oyster reef community.    Missy Southworth
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These components of the VIMS Molluscan Ecology program are listed together in that they go hand in hand. The monitoring data that we collect is used to help guide fisheries management and the industry as well as to assess the effects of restoration efforts.

Programmatically, we have been in the business of monitoring Virginia’s oyster resources since the 1940s. In recent years, collaborative agreement with the Virginia Marine Resources Commission (VMRC) Conservation and Replenishment Department have led to continued oyster monitoring as well as oyster stock assessment and restoration activities throughout Virginia waters. Collaborations with VMRC have also allowed us to begin periodic monitoring of local hard clam resources. Current monitoring efforts include:

Shellstring (spatfall):

The shellstring survey has been conducted annually from late spring through early fall at various sites throughout Virginia’s western Chesapeake Bay tributaries since the early 1940s.  The survey provides an estimate of a particular area’s potential for receiving a “strike” or settlement of oysters on the bottom and helps describe the timing of settlement events in a given year.  This data can be used by parties interested in potential timing and location of shell plantings.


This survey has been conducted annually in the fall since the 1940s and has been a collaborative effort between VIMS and VMRC since the mid 1990s.  The dredge survey is a qualitative survey that provides information about spatfall and recruitment, mortality and relative changes in abundance of small and market oysters from one year to the next.

Patent Tong

This survey has been conducted annually in the fall since 1993 in collaboration with VMRC.  The patent tong survey is a quantitative survey that provides information about spatfall and recruitment, mortality, and changes in abundance and demographics of oyster populations in the Virginia portion of the Chesapeake Bay from one year to the next.

The Virginia Oyster Stock Assessment and Replenishment Archive (VOSARA) data web site is designed to provide graphic summaries of the status of oyster stocks in the Virginia subestuaries of the Chesapeake Bay. Data originates from the patent tong survey.  Summaries provide data by year and historical reef boundaries within each of the described subestuaries.  Oyster populations are described in units of density, oysters per unit area, for each of three size classes: spat are young of the year, small are submarket size (<76 mm length), and market size (>76 mm length) oysters.