New research showing that that mercury levels are higher in some species of tuna could help consumers minimize their consumption of the silvery metal in their sushi and provide a powerful new tool for regulatory organizations. The new researchcombining DNA barcoding at that American Museum of Natural History with analysis of mercury content at Rutgers Universityis published in Biology Letters early online edition and shows surprisingly that tuna sushi purchased in supermarkets might be healthier than that from restaurants. The sushi made for supermarkets tends to be yellowfin tuna.
"We found that mercury levels are linked to specific species," says Jacob Lowenstein, a graduate student affiliated with the Museum. "So far, the U.S. does not require restaurants and merchants to clarify what species they are selling or trading, but species names and clearer labeling would allow consumers to exercise greater control over the level of mercury they imbibe."
"People who eat fish frequently have a particular need to know which species may be high in contaminants," says Michael Gochfeld, professor at Robert Wood Johnson Medical School. "Some agencies have been afraid that any mention of contaminants will discourage people from eating any fish.
Sushi samples for this research project were taken from 54 restaurants and 15 supermarkets in New York, New Jersey, and Colorado. The results are based on 100 samples, all of which were identified with DNA barcoding as either bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares), or bluefin tuna species (Thunnus maccoyii, Thunnus orientalis, and Thunnus thynnus). All samples were tested for relative mercury content.
Combining mercury content and species identification in this study shows that all species exceed or approach levels permissible by Canada, the E.U., Japan, the U.S., and the World Health Organization. Mercury levels are signific
|Contact: Kristin Elise Phillips|
American Museum of Natural History