Mercury accumulates in predatory fish over time, and most tuna sushi (except ours) comes from old, big fish

by Craig Weatherby

As reported by The New York Times yesterday, raw Tuna from several New York City sushi bars and supermarkets contains relatively high levels of mercury.

To anyone in the know, the Times' report by long-time food writer Marion Burros“High Mercury Levels Are Found in Tuna Sushi”comes as a penetrating glimpse into the obvious.

New study affirms purity of Wild Salmon

In an odd coincidence, a brand new study came across our internet transom today, and it shows, once again, that Pacific Northwest Salmon like ours is very low in mercury (Kelly B et al. 2008).

The researchers tested Salmon from British Columbia, Canada, whose wild harvest supplies most of our canned Sockeye (All of our premium frozen Sockeye comes from adjacent Southeast Alaskan waters).

Wild Salmon know no borders, and every one of the many studies conducted to date has found the same low mercury levels in Northwest wild Salmon, whether caught in Alaskan or Canadian waters.

As the authors wrote, “Human dietary exposure calculations indicate intakes… [of mercury]… via... wild BC Salmon are a relatively small percentage of total [mercury] intakes (0.05-32%) compared to other foodstuffs such as fruits, vegetables, chicken and beef (68-99%)… Our findings indicate… wild BC [British Columbia] Salmon remain a safe source of omega-3 intakes for cardio-protective and possibly other health benefits” (Kelly B et al. 2008).

Why were the Times' test results were entirely predictable?

Tuna and other predatory fish accumulate mercury from the smaller fish they eat, which contain low levels of mercury. And Tuna sushi typically comes from larger, older Tuna.

Unfortunately, the Times' coverage buried the fact that certain fishincluding Salmon, Sardines, and small, young Tuna like oursoffer the best of both worlds, being very high in omega-3s and very low in mercury.

Tuna is not inherently high in mercury. For example, we purchase only troll-caught Albacore Tuna that weighs 12 poundsor less, to ensure that it is very low in mercury compared with standard canned or fresh Tuna.

Our Albacore Tuna is caught by our down-the-street neighbor, Paul Hill, who custom-harvests these small, young, sustainable fish just for us (To learn more, see “Vital Choice Tuna: Safer and Tastier”).

(All flash-frozen fish is considered “sushi safe”, because solid-freezing kills any and all unwanted freeloaders in raw fish. But it's smart to select super-fresh premium seafood like ours, which is kept cold until it's flash-frozen within hours of harvest.)

To see the average mercury levels in many more fish species, and test results on Vital Choice tuna, shown in comparison with the FDA maximum safety level, click here.

As the Times' Marion Burros noted, in her accompanying article, titled Studies Link Other Ills to Mercury, Too, “No one is recommending that people stop eating fish, unless their blood mercury levels are dangerously high. In fact, health professionals and researchers encourage eating seafood selectively, choosing species, like Salmon and Sardines, that have high [levels of] omega-3 fatty acids and low levels of mercury” (Burros M, 2008).

Environmental and government agencies alike say that it's safe to enjoy as much wild Salmon as your heart desires (or needs). For more on this, see our Purity Page, and our sidebar.

The mercury debate

Of course, it's wise to minimize intake of mercury, excesses of which cause nerve damage and raise heart risks.

But there is a good deal of debate about the levels at which mercury is actually dangerous: a controversy caused by in part by conflicting research results. For more on this, see “Fight Over Mercury Risks Muddied by Bad Science.

In what is appears to be the most reliable study conducted to date, no harm was detected in 634 children in the Seychelles Islands, even though the children and their pregnant mothers ate far more fish than Americans do.

(The University of Rochester physicians behind the study followed the children at least through age nine, and the investigation is ongoing.)

Scientists who study the subject say the results from the long-term Seychelles study support the hypothesis that the selenium in ocean fish prevents much of the harm that relatively high mercury intake would otherwise wreak. (We covered this topic last year: see “Mercury-Fighting Mineral in Fish Overlooked in Heated Debate.")

Regardless of the debate over the details of mercury toxicity, we agree with those who urge avoidance of the metal, which is why we will only sell low-mercury seafood.

If you want to read more about the relative risk and rewards of eating seafood in abundance, we suggest these articles from our archives:

If you're seeking safe seafood and sushi, turn to Vital Choice… you can enjoy our fish in abundance, worry-free.


  • Kelly B, Ikonomou M, Higgs D, Oakes J, Dubetz C. Mercury and other trace elements in wild and farmed salmon from Britsh Columbia, Canada. Environ Toxicol Chem. 2008 Jan 22;:1 [Epub ahead of print]
  • Burros M. High Mercury Levels Are Found in Tuna Sushi. The New York Times. January 23, 2008. Accessed online January 23, 2008 at
  • Burros M. Studies Link Other Ills to Mercury, Too. The New York Times. January 23, 2008. Accessed online January 23, 2008 at
  • Gorman J. Does Mercury Matter? Experts Debate the Big Fish Question. The New York Times. July 29, 2003. Accessed online January 23, 2008 at