Test of record-breaking tuna confirms correlation between size and mercury levels
by Craig Weatherby and Randy Hartnell
As we’ve reported in several past articles, government and independent tests show a consistent correlation between the size of a tuna and the amount of mercury it contains. Now, the results of tests on a huge, record-breaking tuna confirm those findings, in spades.
Last month, sport fisherman Dan Dillon landed an 873-pound tuna off Delaware. In addition to breaking the size record for Delaware-caught tuna, the enormous fish also broke a record for mercury content.
Mercury levels in the behemoth bluefin—2.5 parts per million (ppm)—were two-and-one-half times higher than the one ppm limit set by the Food and Drug Administration for commercial fish, above which fish cannot be sold. And, they were nearly twice as high as the highest level of mercury ever found in fresh or frozen tuna steaks.
Bigger fish pose bigger risks
Mercury becomes more concentrated as it rises up the ocean food chain, from microscopic organisms to fish. Because tuna, king mackerel, swordfish, sharks, and other predator species occupy the top rungs of the food chain, they contain far more mercury than the smaller fish they prey upon (e.g., herring, sardines, snapper, menhaden).
This is why we select only the smallest, troll-caught Pacific albacore tuna, all of which come from fisherman and nearby Vital Choice neighbor Paul Hill.
As a result, Vital Choice minimal-mercury albacore tuna contain 76 percent less methyl mercury than standard canned albacore (0.08 ppm versus 0.34 ppm), whose processors typically use much larger, older fish.
The mercury levels found in our albacore tuna are 12 times lower than the allowable limit (1 part per million) set by the U.S. Food and Drug Administration (FDA), and six times lower than the recommended limit (0.5 ppm) set by the U.S. Environmental Protection Agency (EPA).
Our perspective on mercury in tuna
A recent analysis by Harvard researchers concluded that the rewards of fish rich in omega-3s outweigh the risks of mercury exposure quite substantially (see "Fish Health Rewards Seen Outweighing Risks").
That said, it makes sense to minimize mercury intake while getting as much uniquely valuable marine omega-3 fat as you can.
Because the mercury levels in Vital Choice albacore are about as low as they get in any tuna, you can enjoy it in moderation with peace of mind.
- FDA Center for Food Safety & Applied Nutrition. Mercury Levels in Commercial Fish and Shellfish. Accessed online August 26, 2005 at http://vm.cfsan.fda.gov/%7Efrf/sea-mehg.html
- Foulke JE. Mercury In Fish: Cause For Concern? FDA Consumer, September 1994. Accessed online August 26, 2005 at http://www.fda.gov/fdac/reprints/mercury.html
- Murray M. Del. tuna breaks another record. The News Journal. August 25, 2005. Accessed online August 26, 2005 at http://www.delawareonline.com/apps/pbcs.dll/article?AID=/20050825/NEWS01/508250360/1006
- Western Fishboat Owners Association. Raw mercury data from 91 samples of younger, 3-5 year old albacore tuna caught by US jig boats in 2003. Accessed online August 26, 2005 at http://www.wfoa-tuna.org/files/general/amtest_idrawdata2004-fixed.pdf