Mercury in Fish: When Catch-and-Release Is Good for You

 By Amy Dickey

Summertime in Utah means hiking, biking, barbecues, fireworks and…fishing! Warm summer days mean more folks are out fishing at Utah’s blue-ribbon streams, high-alpine lakes, reservoirs and urban ponds. Many anglers eat what they catch, which is a good thing, since fish provides important vitamins, minerals and Omega-3 fatty acids that people need for a healthy diet.

Unfortunately, when fishing spots become polluted, your catch may also become contaminated with high concentrations of mercury and other harmful chemicals. Fortunately, Utah has a statewide program that monitors mercury levels in fish and issues advisories to let people know when fish at a particular location are unsafe to eat.

Mercury is a naturally occurring element in our air, soil and water. Atmospheric mercury makes its way into water bodies through rain or snow (wet deposition), or the settling of gases and particles from the air (dry deposition). Other sources of mercury include storm water and industrial discharges. Bacteria in the soils and sediments at the bottom of lakes and streams convert naturally occurring mercury into a more toxic form known as methylmercury. Unlike elemental mercury, methylmercury bioaccumulates in organisms, becoming more concentrated in their bodies the more they ingest. Methylmercury also biomagnifies, meaning organisms contain more of the toxin the higher up they are in the food chain.

Mercury acts as a neurotoxin and has the potential to damage the brain, heart, lungs, kidneys and immune system. Pregnant women and nursing mothers are at risk because methylmercury impacts fetal development and passes from mother to child through breast milk. Young children are also at higher risk because their nervous systems are still developing.

Public health officials in Utah issue fish advisories when mercury levels in fish reach unsafe levels. These advisories provide recommendations on how much of a particular type of fish is safe to eat. Anglers can look up this information by county, water-body, or fish species on the Utah Fish Advisory website.

The Division of Water Quality (DWQ) has teamed with the Division of Wildlife Resources (DWR) and Utah Department of Health (UDOH) to develop collection plans, catch and sample fish, analyze the data, and determine consumption values. Since the Utah program began, more than 3,500 fish have been collected from 280 sites throughout the state, with consumption advisories issued at 23 locations for 13 different fish species.

It’s important to keep in mind that just eight percent of the sites sampled warranted consumption advisories. So remember: You can eat fish—just choose wisely. Know the locations of advisories and the species they include. And enjoy yourself at your favorite lake or reservoir—there are no known health risks associated with swimming and boating in water-bodies with advisories.

Going fishing? Check out the state’s fish advisory website for more information on advisory locations, fish species and recommended consumption amounts. EPA’s Mercury website has additional information about fish consumption, health effects and the ways people can be exposed to mercury. In addition, the Food and Drug Administration recently issued Draft Advice on mercury levels in fish that can help you make informed choices before you purchase fish at a grocery store or restaurant.

I have worked with the Utah Division of Water Quality for 13 years. I Amy Dickeyhave a Bachelor’s degree in Biology and Environmental Studies. When I’m not working, I love to get outside and enjoy all that Utah has to offer. I especially enjoy camping with my husband and two kids.