The Maryland Department of the Environment (MDE) is responsible for monitoring and evaluating contaminant levels in fish, shellfish and crabs in Maryland waters. The tissues of interest for human health include the edible portions of fish (fillet), crab (crabmeat and "mustard"), and shellfish ("meats"). Such monitoring enables MDE to determine whether the specific contaminant levels in these species are within safe limits for human consumption. Results of such studies are used to issue consumption guidelines for recreationally caught fish, shellfish, and crab species in Maryland (see our most recent guidelines). Currently there are no contaminant advisories for oysters and clams (shellfish).
Fish and shellfish can be an important part of healthy diet. They are a good source of high-quality protein and nutrients and are low in saturated fat. A well-balanced diet that includes a variety of fish and shellfish can contribute to a child’s proper growth and development. In addition, the American Heart Association recommends that adults eat fish at least twice a week for a healthier heart.
Many fish, including the most popular store-bought fish and shellfish, are safe to eat. Some, however, contain chemicals (such as methylmercury, polychlorinated biphenyls (PCBs), and various types of pesticides) that may harm children and adults. The Maryland Department of the Environment monitors and evaluates contamination levels in fish, shellfish, and crabs throughout Maryland and issues guidelines for recreationally caught fish (see our most recent guidelines). The U.S. Food and Drug Administration (FDA) issues nationwide guidance for commercial fish (fish bought in stores and restaurants). In March 2004, the FDA together with the Environmental Protection Agency (EPA) released the following national guidelines for women who may become pregnant, pregnant women, nursing mothers, and young children:
For more information about the federal guidelines visit
Find Out How To Protect Your Health While Eating Fish
FDA Information on Fresh and Frozen Seafood
U.S. EPA Fish Consumption Website
Mercury Levels in Commercial Fish and Shellfish (U.S. EPA/FDA)
The Maryland Department of the Environment has monitored chemical contaminant levels in Maryland’s fish since the early 1970s.
Maryland routinely monitors across the state on a 5-year cycle. When routine monitoring indicates potential hazards to the public and environment, additional monitoring of the affected area may be conducted to verify the initial findings and identify the appropriate species and size classes associated with harmful contaminant levels. Findings from such studies are the basis for the fish consumption guidelines (see our most recent guidelines).
The types of fish sampled include important predatory game species (such as small mouth bass and striped bass), common recreational panfish species (white perch, bluegill, crappie) as well as,bottom dwelling, accumulator species with relatively high fat content (such as carp, catfish and American eel). Also, periodically MDE conducts intensive surveys of contaminant levels in selected species in specific water bodies. Past targets of intensive surveys conducted in Patapsco River/Baltimore Harbor included: white perch, channel catfish, eel, and striped bass.
Fish Consumption Guidelines in Neighboring States & Jurisdictions
Chesapeake Bay Regional Fish Consumption Advisories (Chesapeake Bay Program)
National Listing of Fish Advisories (EPA)
Information on Fish
Fishing Information (Maryland DNR)
Maryland Biological Stream Survey (Maryland DNR)
Risk-Based Screening of Metals in Maryland Finfish Tissue, 1985-1997 (MDE)
Fish Kills in Maryland (MDE)
Information on Mercury
Mercury Information (MDE)
Toxicological Profile for Mercury (ATSDR)
Fish Tissue Criterion for Methylmercury (EPA)
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