Document Type



Virginia Institute of Marine Science

Publication Date



CBP/TRS 107/94


Benthic macroinvertebrate assemblages have been an integral part of the Chesapeake Bay monitoring program since its inception due to their ecological importance and their value as biological indicators. The condition of benthic assemblages reflects an integration of temporally variable environmental conditions and the effects of multiple types of environmental stresses. As such, benthic assemblages provide a useful complement to more temporally variable chemical and water quality monitoring measures.

While assessments using benthic monitoring data have been useful for characterizing changes in environmental conditions at individual sites over time, and for relating the condition of sites to pollution loadings and sources, the full potential of these assessments for addressing larger management questions, such as "What is the overall condition of the Bay?" or "How does the condition of various tributaries compare?" has not yet been realized. Regional-scale assessments of ecological status and trends using benthic assemblages are limited by the fact that benthic assemblages are strongly influenced by naturally varying habitat elements, such as salinity, sediment type, and depth. Such natural variability confounds interpretation of differences in the benthic community differences as simple responses to anthropogenic environmental perturbations. An additional limitation is that different sampling methodologies used in various programs often constrain the extent to which the benthic data can be integrated for a unified assessment.

The objective of this project was to develop a practical and conceptually sound framework for assessing benthic environmental conditions in Chesapeake Bay that would address the general constraints and limitations just described. This was accomplished by standardizing benthic data from several different monitoring programs to allow their integration into a single, coherent data base. From that data base a set of measures (Chesapeake Bay Benthic Restoration Goals) was developed to describe characteristics of benthic assemblages expected at sites having little evidence of environmental stress or disturbance. Using these goals, benthic data from any part of the Bay could be compared to determine whether conditions at that site met, were above, or were below expectations defined for reference sites in similar habitats.


Benthos -- Chesapeake Bay (Md. and Va.)

Publication Statement

Prepared for U.S. Environmental Protection Agency, Chesapeake Bay Program Office and the Maryland Governor's Council on Chesapeake Bay Research Fund, Chesapeake Bay Research and Monitoring Division, Tidewater Administration, Maryland Department of Natural Resources



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