Some Local Fish May Have Higher Mercury Content

By FRANK CARINI/ecoRI News staff

BRISTOL, R.I. — The federal government advises women who are or may become pregnant, nursing mothers and young children not to gorge on several marine species, namely swordfish, albacore tuna, shark, king mackerel and tilefish, because of the concentration in the tissue of these fish of methylmercury, a highly toxic organic compound of mercury.

But what about fish that are more commonly caught in Narragansett Bay, Rhode Island Sound and Block Island Sound, especially by recreational anglers? Since 2005, Roger Williams University marine biologist David Taylor has been studying the methylmercury content in the tissue of bluefish, striped bass, black sea bass, tautog, and winter and summer flounder.

And thanks to a recently awarded grant from Rhode Island Saltwater Anglers Foundation for $12,166, Taylor will expand his research to measure mercury levels in scup, a native fish found primarily in the Atlantic and frequently fished and consumed by local recreational fishermen. These seven species account for 99 percent of the Ocean State’s recreational fishery, according to Taylor.

“We are very pleased to offer this grant in support of Taylor’s important research into mercury levels in our local scup,” said Steve Medeiros, president of the Rhode Island Saltwater Anglers Foundation. “This is an important fish caught by local anglers and consumed by thousands of people. Our foundation believes that this research will aid everyone to determine if consumption of scup could lead to exposure to mercury.”

During the next year, Taylor and RWU marine biology student Sean Maiorano will analyze mercury levels of scup to enable the state Department of Health (DOH) to update fish consumption advisories, should a change in mercury risk be identified. The effort is aimed at encouraging safe, healthy consumption of scup, a fish Taylor anticipates will measure low in mercury levels.

Taylor and Maiorano began their research this month by collecting about 100 scup samples from Narragansett Bay, Rhode Island Sound and Block Island Sound. When their analysis is concluded, consumption advisories will be created for scup and the other six recreational fish being studied.

Taylor’s ongoing research soon will assist the DOH in establishing new guidelines for safely eating these seven popular local species. While swordfish and tuna are notably identified as fish that should be eaten in moderation because of high mercury levels, little information has been recorded on the mercury levels of native fish that are heavily fished and consumed by New Englanders.

State-issued fish consumption advisories generally are based on nationally aggregated data, but regional data is critical to more accurately assess mercury levels in local species. Based on eight years of research, Taylor has concluded that the mercury levels of local striped bass, bluefish and flounder don’t reflect nationally aggregated data and often underestimate the mercury risk.

“Since the current consumption advisories for local marine fish are based largely on nationally aggregated data, they may be overly or insufficiently protective in limiting mercury exposure,” Taylor said.

His research shows that recreational fishermen generally consume higher quantities of fish than the average American, and thus may be more susceptible to mercury poisoning, which can cause damage to the nervous system, the immune system and heart. To determine how much fish and what species area residents are consuming, Taylor surveyed eating habits of 280 local fisherman and their families and found that they eat 80 percent more fish relative to the national average.

Mercury is a toxic environmental contaminant affecting human health, and exposure occurs mainly through dietary consumption of contaminated fish. To minimize such exposure, federal public health officials and state agencies issue consumption advisories to inform consumers of the possible health risks associated with eating fish. While consumption advisories have been developed on a site-specific basis for fish inhabiting freshwater systems, advisories regarding the consumption of saltwater species lack geographic specificity.

Taylor has performed comprehensive research on mercury contamination in other recreational fish from Narragansett Bay, including striped bass, bluefish, tautog, black sea bass, summer flounder and winter flounder. The updated DOH advisories will be based on data from this new research in addition to Taylor’s previous research on these key species.

Avoid eating bass, pike, tilefish, king mackerel and pickerel, according to the DOH website. Swordfish, shark, bluefish, striped bass and freshwater fish, with the exception of stocked trout, that are caught in Rhode Island should not be eaten, according to the DOH. Although mercury levels in bluefish and striped bass are low, the Food and Drug Administration cautions against eating these fish because of the presence of other contaminants such as as polychlorinated biphenyls (PCBs). Limit black crappie and eel consumption to one meal a month, and eat smaller fish and vary the types of fish that you eat, according to the DOH.

Taylor said there is a higher mercury content in some locally caught species, such as bluefish and striped bass, compared to national data. The slightly higher averages here are likely due to Rhode Island’s prominent role in the Industrial Revolution — there’s a lot of legacy mercury in local sediment — and wind-blown pollution from Midwest power plants, Taylor said.

“You can get rid of mercury, but it’s a very slow process,” said Taylor, referring to the amount of mercury flowing through the food web. “You take it in much more quickly.”

That said, Taylor isn’t sounding an alarm regarding the consumption of local fish. “By no means is my message to not eat fish. It’s a super food and great for way to promote health. We just need a better understanding of the mercury in the local fish we are eating so we can make more educated choices.”