Validating Acoustic Sensing Techniques to Detect Habitat Changes in Oyster Reefs

Principal Investigator:

Gary F. Smith

Start/End Year:

2003 - 2006


Cooperative Oxford Laboratory

Co-Principal Investigator:

Roger I.E. Newell, Horn Point Laboratory, University of Maryland Center for Environmental Science; Roger L. Mann, Virginia Institute of Marine Studies; Clyde Mackenzie, Howard Marine Sciences Laboratory



Lack of detailed knowledge regarding the spatial extent and character of Chesapeake Bay oyster habitat greatly hinders our ability to assess and effectively manage the resource. Oyster restoration activities are presently applied piecemeal, and are not scaled to the true size of the habitat. Population assessments and models lack the most basic information concerning area habitat quality, and antecedent geological controls that appear to govern the natural oyster bed location, evolution, and survival. We propose to develop GIS integrated remote acoustic survey techniques that will allow a more realistic assessment and quantification of oyster habitat. Principal to this system will be newly advanced Acoustic Seabed Classification Systems (ASCS) technology. Such remote acoustic surveying equipment allows for the statistically based classification of bottom habitat. In addition, side scan sonar and sub bottom profiling will compliment the ASCS adding to the Geographic Information System (GIS) based imagery of the oyster habitat. Underwater video will be used to ground-truth the acoustically collected data. This project will operate on the concept of a platform or system approach, where both acoustic techniques and validation methods are collected in common, processed and linked via the same GIS system. We expect to apply new techniques in representational analysis in producing habitat charts. This approach will provide a more realistic representation of bottom heterogeneity and transitions within an oyster bed than has been previously available. A key objective of bringing together these remote technologies is the belief that long and short term effects of harvest gear on this resource can be identified and quantified through display and analysis of these GIS linked techniques. It is also envisioned that temporal change within an oyster bar can be detected. Detailed information on bottom character, including relief and morphology, internal sediment layers, evidence of sediment movement and deposition, and presence of sessile benthic organisms will be value-added data that adds to oyster bed understanding. An overriding aspect of this work is that such detailed mapping will, for the first time, provide the basis for a structured management of the resource, where restoration activity can be designed, carried out, and evaluated over the broad scales of the oyster habitat. With such understanding, new, restoration techniques are likely to be found that will move the Chesapeake towards the well publicized goal of increasing oyster populations ten-fold in the foreseeable future. Finally, these remote technologies may be used to determine what levels of harvest activity exert negative effects on oyster habitat integrity.

Related Publications:

Smith, GF; Bruce, DG; Roach, EB; Hansen, A; Newell, RTE; McManus, AM. 2005. Assessment of recent habitat conditions of eastern oyster Crassostrea virginica bars in mesohaline Chesapeake Bay. North American Journal of Fisheries Management25(4):1569 -1590. doi:10.1577/M04-058.1. UM-SG-RS-2005-21.

Smith, GF; Roach, EB; Bruce, DG. 2003. The location, composition, and origin of oyster bars in mesohaline Chesapeake Bay. Estuarine Coastal and Shelf Science56(2):391 -409. doi:10.1016/S0272-7714(02)00191-9. UM-SG-RS-2003-27.

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