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Home , Mercury in fish, Shrimp, Shrimp fishery, Sustainable fishery, Sustainable seafood

April 2011 / Vol. 7

Healthy, Sustainable : A Study of in by Sarah J. Nelson and Catherine Schmitt Background Mercury is a highly toxic element that can impair brain development in children, and affect , , vision, and muscle coordination in . Many watersheds in the Northeast have relatively high mercury concentrations for the US, because the region is downwind of major sources. Mercury is especially active in aquatic environments, so people are exposed to mercury primarily through the consumption of . Shrimp, the most popular seafood in the , is often touted as a “low-mercury” seafood choice, although available information is not specific to Maine’s native shrimp . This study intended to answer two questions: Are shrimp truly a low-mercury ? Does it matter where the shrimp come from?

Marine Research in focus provides updates on marine research for coastal communities. This fact sheet was produced by Maine Sea Grant with programing support provided by University of Maine Cooperative Extension. Methods We purchased three types of frozen, headless shrimp from a Maine supermarket: Maine Northern shrimp (), Louisiana brown shrimp (Farfantepenaeus aztecus), and tiger shrimp ( monodon). After lab tests confirmed that shrimp had similar concentrations of mercury along the whole length of the edible part1 of their bodies, a section of shrimp was analyzed in the University of Maine’s Sawyer Research Laboratory to determine total mercury concentration in each individual shrimp.

Why Study Shrimp? Shrimp is the number one type of seafood consumed in the United States – over 1.2 billion pounds in 2009 ( Statistics Division 2010). While shrimp is promoted as a “low-mercury” seafood choice, few2 studies have looked at mercury in commercially available shrimp. The current safety level is based on only 24 samples from the 1990s3, and the species is only identified for a few of those samples4, even though several different species of shrimp are available to consumers. Most shrimp consumed in the US is imported from farms in , but Maine has its own wild shrimp , for Pandalus borealis or Northern shrimp. This is a small but that employs fishermen in the winter months. Maine shrimp are typically available fresh from December through April and frozen year-round.

1. Some people do cook and/or consume shrimp whole with the shell, however we analyzed them headless and without shells, as most consumers prepare them. 2. One study found that shrimp do accumulate mercury rapidly when they are in a high mercury environment (Palmer and Presley 1993); another study in (which did not say which species/origin shrimp they used) found low-mercury in shrimp and noted that bigger shrimp tended to have less mercury (Burger et al. 2005). We are not aware of any studies that determined mercury in commercially available Maine wild-caught shrimp. 3. http://www.fda.gov/Food/FoodSafety/Product-SpecificInformation/Seafood/FoodbornePathogensContaminants//ucm115644.htm 4. http://www.fda.gov/Food/FoodSafety/Product-SpecificInformation/Seafood/FoodbornePathogensContaminants/Methylmercury/ucm191007.htm Average and maximum mercury concentrations in shrimp and other seafood

This Study All samples were very low in mercury, in agreement with the existing FDA data. Mercury in commercially-available shrimp Mercury in shrimp for all samples taken together (“All Mercury in commercially-available shrimp shrimp” bar) averaged 21 ppb, ww (parts per billion, wet weight). The range of values in our study was 4 – 66 Maine EPA ppb, ww. Although there were statistically significant Gulf of MexicoMaine Maine mercuryEPA guideline differences among the three types of shrimp we Gulf of MexicoThai mercuryMaine mercury guideline studied, these differences are not meaningful for Thai mercury guideline consumption because the levels of mercury All shrimp guideline All shrimp are so low. The differences among the types of shrimp 0 100 200 300 raise interesting research questions, such as, Does 0 100 200 300 shrimp size matter? What is the difference between Total mercury, ppb ww farm raised and wild shrimp? Total mercury, ppb ww

Mercury in commonly-eaten seafood (FDA data) Mercury in commonly-eaten seafood (FDA data) Shrimp EPA mercury guideline ShrimpClam EPA mercury guideline (fresh/frozen) Maine mercury Salmon (fresh/frozen) guidelineMaine mercury HaddockCrab guideline Freshwater troutCrab FreshwaterFreshwater Average CannedFreshwater light perch Average Canned lightLobster tuna Maximum (saltwater, striped, black) Maximum Bass (saltwater, striped, black) Canned albacoreHalibut tuna Canned albacoreSword sh tuna Sword sh 0 300 600 900 1200 1500 1800 3000 3300 FDA Data 0 300 600 Total900 mercury,1200 ppb ww 1500 1800 3000 3300 Total mercury, ppb ww The Maine Center for Control and Prevention and the Environmental Protection Agency set limits on the level of that is considered safe to eat. Maine’s guideline is stricter, to protect sensitive like children and pregnant women. The average mercury concentration in shrimp in this study (21 ppb) is 10 times lower than Maine’s fish tissue action level of 200 ppb. Even the one shrimp with the highest mercury concentration (66 ppb) still had three times less mercury than Maine’s action level. By comparison, EPA recently found that approximately half of the sampled from 76,559 across the US had mercury concentrations that exceeded the EPA’s recommended safety level of 300 ppb (US EPA 2009).

References Burger J., A.H. Stern, M. Gochfeld. 2005. Mercury in commercial fish: optimizing individual choices to reduce risk. Environmental Health Perspectives 113:266-271. Fisheries Statistics Division. 2010. Fisheries of the United States 2009. Silver Spring, MD: National Marine Fisheries Service. http://www.st.nmfs.noaa.gov/st1/fus/fus09/index.html Palmer, S.J., B.J. Presley. 1993. Mercury by shrimp (Penaeus aztecus) transplanted to Lavaca Bay, Texas. Bulletin 26:564-566. US EPA. 2009. The National Study of Chemical Residues in Fish Tissue, EPA-823-R-09-006. Washington, DC: US Environmental Protection Agency Office of . Conclusion Balancing safety, nutritional value, affordability, and environmental concerns when making food decisions is challenging for many Maine families. This study provided more data to support the assertion that people who are concerned about mercury should feel comfortable shrimp, including Maine shrimp. Shrimp are a low- fat, healthy protein source, and Maine shrimp are a local, affordable, and sustainably managed seafood choice. Maine Safe Eating Guidelines According to the Maine Department of Environmental Protection, mercury levels in Maine fish, loons, and are among the highest in North America. This has led the Maine Center for Disease Control and Prevention to issue a statewide advisory recommending that pregnant women, women of childbearing age, and young children limit their fish consumption based on the type of fish they consume. The advisories have been in place since 1994 and remain in effect today because mercury levels in fish have not decreased. Currently 49 states, including Maine, have fish consumption advisories due to mercury . http://www.maine.gov/dep/mercury/ The Maine Safe Eating Guidelines set fish consumption limits to protect everyone. http://www.maine.gov/dhhs/eohp/fish

The Maine Family Fish Guide: Advice from the Maine Center for Disease Control and Prevention Healthy Fish for Pregnant Women and Families Fish: 2 Meals a Week for Good Health Eat 2 Meals a Week of Different Fish for pregnant women, children, and adults Fish low in mercury and high in Omega 3 fish oils Fish low in mercury Find the Facts Fast Buy HealthyCook Fish for Pregnant Women and Families: Best Fish to Eat and Fish to Avoid Eat 2 Meals a Week of Different Fish • Family-Friendly Fish: Eat 2 Meals a Week of Different Fish...... Page 3 • High Mercury Fish to Limit or Avoid ...... Page 4 Best Choices Light and Haddock, , How to Buy, Cook, Eat Fish Out Seafood High in Omega 3 Oils and Low in Mercury Fresh Salmon Smelt Atlantic Canned Tuna and • Salmon – fresh and canned • Don’t Buy Smelly Fish! ...... Page 5 Try budget friendly canned salmon. See recipe on page 10. • Pull-Out Poster: Healthy Seafood 2 Meals A Week ...... Page 6 High Mercury• Fish and to Limit or Avoid Don’t Buy Smelly Fish! • Fish for Dinner: Cook In or Eat Out...... Page 8 • Smelt Buy Fresh Fish Advice for• Pregnant and Nursing Women, Tuna, Fish Sticks, Salmon, and Fish You Catch Women Who• May Get Pregnant, and • Buy fish in places you trust. Ask when the fish you plan to buy • OK to Eat Tuna, Fish Sticks, Farm-Raised Fish ...... Page 9 Children Under Age 8 came in. If Cannedit’s more than Salmon a day or two old, choose Sardines another kind. Mussels Lobster Imitation Shrimp • Salmon: 3 Choices for Taste, Health, and Budget ...... Page 10 More Great Choices • Check that fish has been properly iced or kept in a refrigerator. and and Lobster Fish to Avoid: Pregnant and nursing women, women who may get Ask to smell it. It should smell fresh and mild, not strong or “fishy.” • Fish You Catch in , Lakes, or the ...... Page 11 pregnant, and childrenOther underSeafood age 8 shouldLow NOTin Mercury, eat these 4 fish. but Not as High They’re too highin in Omega mercury: 3 Fish Oils • Ask for recipes. For more information: •• SwordfishLight Canned Tuna Don’t Eat These Fish! • Buy Frozen Fish General information: http://www.maine.gov/dhhs/eohp/fish/ • Scallops and Clams If you are pregnant, nursing, may get pregnant or a child under 8 •• KingShrimp Mackerel – fresh, frozen, canned, from Maine and away Cooking fish: www.deliciousdecisions.org/cb/rec.html • Frozen seafood is just as healthy as fresh. Just make sure the packages (under Main ingredients, check seafood, scroll to bottomC andatch click submit) •• TilefishFlounderEat Out and Sole are sealed tight, not torn or crushed on the edges. Also don’t buy • Shark • • These fish are high• Haddock, in mercury Hake, because Pollock, they and eat Cod other fish or live packages covered in frost or ice crystals. This could mean the fish has Buying fish: www.ocean.udel.edu/mas/seafood/handling.html been stored a long time or thawed and refrozen. Everyone else can eat 2 meals a month of these 4 fish a long time. Mercury• Imitation can damage Crab or a Lobsterbrain starting (This is to made form from or grow. various fish.) For health information about mercury in fish or omega 3 oils, call Maine CDC If you’re pregnant,That’s this why sign babies means in the womb, caution nursing babies, and young children • If you see the letters FAS, they mean Frozen At Sea. toll-free in Maine: 1-866-292-3474 • Lobster – but do not eat tomalley, the green stuff inside the body are at most risk. When you buy FAS fish, it may still be frozen or it may be thawed. It’s safe to buy either way. Fish to Limit: Pregnant and nursing women and children under age Questions? Call the Maine CDC toll free in Maine: 1-866-292-3474 Environmental and Occupational Health Program, This brochure was produced with funding from the U.S. 8 may safely eat one meal per week of one of these fish. Choose Maine Center for Disease Control and Prevention, DHHS Environmental Protection Agency Cooperative Agreement Why are Omega 3 fish oils important? Omega 3 fish oils are “brain (formerly Bureau of Health} #CR82628301-0 other fish listed on page 3 for the 2nd that week. Store Fish Safely 11 State House Station, Augusta, ME 04333 food” for babies in the womb and babies who are nursing. These oils also • Tuna TTY: (800)606-0215 In accordance with Federal laws, the Maine Department of help protect adults from heart attack . Fish is also a great source of • Best to cook and eat, or freeze, fresh fish (and thawed FAS fish) Produced December 2005 Gov. John Elias Baldacci Health and Human Services does not discriminate on the basis of sex, age, color, national origin, or disability in admission or •protein, White zinc canned and tuna and (see is low page in saturated 9) fat. within 2 days of purchase. You can safely keep fresh fish that you In collaboration with: AHEC Health Literacy Center, access to or treatment or employment in its programs and buy or catch in the freezer for up to 3 months. Mark the date on University of New England, Biddeford, Maine activities. The Department’s Affirmative Action Coordinator has • Halibut steak Design: Campbell Creative been designated to coordinate our efforts to comply with and Most farm raised fish are safe to eat. See page 9. For farm raised salmon, the package! Thanks to these community partners who helped decide and test content, language, implement these Federal laws and can be contacted for further see page 10. and graphics: Franklin County Children’s Task Force, York County Alliance for information at: 221 State Street, Augusta, Maine 04333, (207) • Fish that you buy frozen should go right into your freezer when Healthy Families, Knox County Parents as Teachers, Maine Nutrition Network 287-2567, or Hearing Impaired call 1-800-606-0215. Advice for Everyone Else you get home. Don’t let it thaw3 until ready to cook. Fish to Limit: Other adults and children over age 8 may safely eat It can stay in the freezer for up to 3 months. up to 2 meals per month of swordfish, shark, king mackerel, and tilefish. These fish are high in mercury because they eat other fish or • If fish smells strong or feels slimy, throw it out. Don’t cook it live a long time. Too much mercury lowers the heart healthy benefits of or eat it. Omega 3 fish oils.

Limits on Fish You Catch: See eating limits for sport caught fish (fish from Maine rivers, lakes, ocean) on page 11.

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Acknowledgements Maine Sea Grant provided funding and support for this research. The Senator George J. Mitchell Center at the University of Maine provided support to S.J. Nelson for participation in this work. M. Lagerklint and C. Devoy at the Sawyer Environmental Chemistry Research Laboratory at the University of Maine analyzed samples. K. Johnson of Husson University and staff from the Maine Center for Disease Control and Prevention provided constructive comments and information about Maine’s human health guidelines.

Funding provided by:

Maine Sea Grant supports marine science research and outreach activities. Based at the University of Maine, our coastwide program works in partnership with marine industries, scientists, agencies, private organizations, and a wide range of marine resource users. For more information on the activities of the Maine Sea Grant College Program at the University of Maine, please call 207.581.1435 or visit our website at www.seagrant.umaine.edu.

Edited by Catherine Schmitt, Maine Sea Grant; Design by Kathlyn Tenga-González, Maine Sea Grant. Photos—Cover, shrimp: NOAA; seafood: Kathlyn Tenga-González. Page 2: Ken La Valley. In complying with the letter and spirit of applicable laws and pursuing its own goals of diversity, the University of Maine shall not discriminate on the grounds of race, color, religion, sex, sexual orientation, including transgender status or gender expression, national origin, citizenship status, age, disability, or veteran’s status in employment, , and all other areas of the University System. The University provides reasonable accommodations to qualified individuals with disabilities upon request. Questions and complaints about discrimination in any area of the University should be directed to the Director of Equal Opportunity, the University MSG-E-10-16 of Maine, 5754 North Stevens Hall, Room 101, Orono, ME 04469-5754, telephone (207) 581-1226, TTY (207) 581-9484. NA06OAR4170108