In 1977, MDE established a statewide water-quality monitoring network in the Maryland portions of the Chesapeake Bay and its tributaries. As part of this effort, whole fish have been analyzed yearly for a group of metals and pesticides known to concentrate in fish. This enables managers to identify compounds that may be undetectable in water samples, but detectable in fish tissue. While this monitoring program did not focus specifically on the safety of fish for consumption, it was recently modified to address this concern. Samples from within each of these areas are taken every three years.
Collections consist of two samples of accumulator species and one sample of game species.
Of the accumulator samples, one includes whole fish, while the second includes only fillet tissue. Of the game species, only the fillet portion is analyzed. This allows water-quality managers to evaluate the relative levels of contaminants of concern accumulating in state waters, and contaminant levels in the fish to determine safety for human consumption. The species surveyed have included white perch, spot, channel catfish, brown bullhead, American eel, bluefish, striped bass, and blue crab. Since the early 1970s, MDE has been surveying metal and pesticide levels in oysters and clams from the Chesapeake Bay and its tributaries.