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Fish Mercury and Human Health Advisories

Florida’s freshwater and marine fish are generally considered safe to eat.  However, certain fish can be potentially unhealthy to eat because those fish can take up contaminants from the water they live in and from the food they eat.  Fish may contain different levels of contaminants based on their location, size, age, length of life, and feeding habits. Although pesticides, algal toxins, and other manmade compounds are of interest to health officials, mercury is currently the contaminant of greatest concern in Florida’s fish.

Redear sunfish, bluegill, and largemouth bass are collected  for routine mercury testing from state waters. Photo credit: FWC

Since 1983, the Florida Fish and Wildlife Conservation Commission (FWC), the Florida Department of Environmental Protection (DEP), and the Florida Department of Health (DOH) have been actively investigating the occurrence of mercury in Florida’s freshwater and marine environments.  This multi-agency effort has focused on surveying important marine and freshwater bodies and species of fish throughout the state. 

Fish consumption advisories for specific water bodies are issued when contaminants found in fish are at levels that may pose a risk to human health.  DOH, in cooperation with DEP and FWC, issues fish consumption advisories.  FWC biologists collect species of concern; DEP scientists analyze fish tissue for mercury, and DOH officials conduct risk assessments and issue fish consumption advisories.  Advisories for mercury in Florida waters have been issued since 1989. The advisories are not intended to discourage anglers from eating fish but should be used to choose fish lower in mercury while limiting consumption of some species of fish from certain waters. 

Many Florida waters have been tested for mercury levels in fish.  For these, the DOH Web site offers regularly updated consumption advisories containing specific advice about eating fish from Florida’s fresh and marine waters. Visit www.doh.state.fl.us/floridafishadvice to view the advisories. The DOH can also be contacted through regular mail or by telephone:

Florida Department of Health
Bureau of Community Environmental Health
4052 Bald Cypress Way Bin# A08
Tallahassee, FL, 32399-1712
(850) 245-4299

Consumption advice about commercially caught fish sold in supermarkets and restaurants can be found in the joint Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) online publication, Joint Federal Advisory for Mercury in Fish. Advisories from other states and tribal agencies are also available online.

Joint Federal Advisory for Mercury in Fish:
www.epa.gov/waterscience/fishadvice/advice.html

EPA National Listing of State, Territory, and Tribal Advisories:
www.epa.gov/waterscience/fish/states.htm

Certain species have high contaminant levels and should be avoided, while authorities advise limited consumption of other species.  Mercury testing in Florida freshwaters has focused on sportfish species, including largemouth bass, bluegill, redear sunfish, warmouth, spotted sunfish, redbreast sunfish, black crappie, catfish, and some exotics such as oscars, butterfly peacocks, and Mayan cichlids.  Much of the testing has focused on largemouth bass since their feeding habits and long lifespan create the greatest potential to accumulate high levels of mercury.  Some species such as bluegill, redear sunfish, redbreast sunfish and spotted sunfish are generally low in mercury throughout the state; however, it is a good idea to review the current fish consumption advisory for specific advice on these species.

Removing muscle tissue from a largemouth bass (top) and Spanish mackerel (bottom) for mercury testing. Photo Credit: FWC

Mercury testing of fish from marine and estuarine waters of Florida has included over 100 species, representing all major groups from primary consumers to apex predators.  Apex predators are fish at the top of the food chain.  These species include many popular sportfish collected from state waters.  The majority of marine and estuarine fishes examined contained low levels of mercury, but levels in individual fish varied greatly within and among species.  Examples of species with low levels include striped mullet, Florida pompano, sheepshead, common dolphin, gray snapper, gulf flounder, and southern flounder.  Many other species also contain low mercury levels.  The current fish consumption advisory provides specific advice regarding Florida marine fishes.
FWC conducts sampling and research programs to further understand the significance of mercury in Florida’s aquatic environments and to determine the range and extent of contamination in fish. These results will be used to update fish consumption advisories.  Please refer to the DOH Web site for periodic updates of information about new and existing water bodies.

Visit http://www.doh.state.fl.us/floridafishadvice for more information.