[en] High-resolution gamma spectroscopy was used to determine radionuclide concentrations in sediment, finfish, shellfish, and aquatic vegetation collected from the Chesapeake Bay in the vicinity of the Calvert Cliffs Nuclear Power Plant (CCNPP) during 1985-1986. Low concentrations of radionuclides attributable to CCNPP (Ag-110m, Co-58, Co-60, and Zn-65) were detected in all biota (except edible finfish) and in sediments. Silver-110m was the principal CCNPP-related radionuclide detected in biota (particularly oysters); Co-58 and Co-60 were the principal CCNPP-related radionuclides detected in sediments. CCNPP-related radionuclide concentrations detected in Bay biota and sediments were within ranges observed in previous years and represent small increments to radionuclide concentrations in the Bay relative to natural and weapons test levels