 As a result, Mussel Watch can be used to ““monitor spatial distributions and temporal trends of chemical concentrations in coastal and estuarine regions of the US.”

There is not a single species of mussel or oyster that is common to all US coastal regions, so the species for a given site are chosen based on their abundance and ease of collection.“Mussels ("Mytilus" species) are collected from the North Atlantic and Pacific coasts, oysters ("Crassostrea virginica") from the mid-Atlantic (Delaware Bay) southward and along the Gulf Coast, and zebra mussels ("Dreissena" species), an invasive species, are collected from sites in the Great Lakes.”

The majority of field collection and laboratory work is conducted by non-NOAA contract laboratories.At least once annually between November and March volunteers at each Mussel Watch site collect two groups of 50-100 bivalves.