Toxic tuna

The mercury problem isn't contained to New York City's sushi restaurants and markets

Posted by Andrew Sharpless (Guest Contributor) at 1:12 AM on 25 Jan 2008

Read more about: food | toxics | mercury | fishing | New York City

In case you needed another reason not to consume the dangerously overfished bluefin tuna: This week, The New York Times had a story about a study of mercury contamination, conducted by the newspaper, of leading sushi restaurants in New York. Guess which species showed the highest level of mercury? In the study, the Times collected samples of tuna sushi from leading restaurants like Blue Ribbon Sushi and Nobu Next Door. The results "found so much mercury in tuna sushi from 20 Manhattan stores and restaurants that at most of them, a regular diet of six pieces a week would exceed the levels considered acceptable by the Environmental Protection Agency."

In addition, the Times noted that "sushi from 5 of the 20 places had mercury levels so high that the Food and Drug Administration could take legal action to remove the fish from the market." In a sidebar about the health risks related to mercury, the Times noted that "several studies have concluded that elevated mercury levels may be associated not only with neurological problems but with cardiovascular disease among adults as well."

Sushi made from bluefin showed the highest level of mercury. As the Times report noted, their findings "reinforce results in other studies showing that more expensive tuna usually contains more mercury because it is more likely to come from a larger species, which accumulates mercury from the fish it eats." In addition to the high levels of mercury found in bluefin tuna, there is also the consideration that the population of the mighty fish is under such pressure that many are calling for an Atlantic-wide moratorium on catching bluefin.

The findings prompted famed restaurateur Drew Nieporent (owner of Nobu, Nobu Next Door, and Tribeca Grill) to comment: "I'm startled by this. Anything that might endanger any customer of ours, we'd be inclined to take off the menu immediately and get to the bottom of it."

This is not just a problem in New York's sushi bars. Today, in a bit of serendipity, Oceana released a study showing high mercury levels in fresh tuna, other sushi, and swordfish from sushi bars and grocery stores from cities across the country. I hope that others who sell sushi and other fish also take the FDA warnings on mercury and seafood to heart, and also get on board and support efforts to reduce the amount of mercury that finds its way into our oceans (and ultimately our diets).

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11 Comments | Post a Comment

Toxic Tuna

Thank you, Andrew Sharpless, for reminding people that the slivers of sushi on their plate comes from a creature that lived in the sea, sometimes for many years, and is now dangerously overfished. Thank you for bringing the fish to the table in the discussion of mercury and fish consumption. Healthy, tasty and ethical alternatives to consuming animals and their by-products are now widely available, leave the fish in the ocean !
Dale Ball

by dale ball at 4:13 AM on 25 Jan 2008

tuna grades

The reason why those sushi samples were so high in mercury was because they were very old, large, and fatty bluefin. Methyl mercury takes a long time to bio-accumulate in fatty tissue. So one would expect the most expensive grades of sushi to have the highest methyl mercury levels.

Thus it is erroneous to say all bluefin tuna or that all pelagic fish have high mercury levels. This is simply not true.

Onward through the fog

by Sam Wells at 9:43 AM on 25 Jan 2008

Maybe not all bluefin are contaminated, but...

...there are very few "old, large" bluefin left. It's most likely at least some, if not all, the bluefin sushi was from smaller fish. The population is in severe decline and most fish are caught before they get the chance to be old and large. The WWF has a good summary of the growing bluefin crisis.

Oceana: Protecting the world's oceans.

by suzannah at 10:19 AM on 25 Jan 2008
[ Parent ]

support your claim

Do you have a link that shows the bio-accumulation of methylmercury in fatty tissues is slow and not all fish have it?

Here's a link that says that many variables determine mercury levels, in any fish:

http://www.ec.gc.ca/MERCURY/EH/EN/eh-ec.cfm

"In general, levels of mercury increase with fish size and age, although not always. Levels also vary by species and location. Bioaccumulation in fish is influenced by the amount of methylmercury present, which is in turn affected by local biogeochemical processes and by mercury inputs from atmospheric pollution."

by freeztar at 11:57 AM on 25 Jan 2008
[ Parent ]

We make it easy...

Making fish choices based on sustainability is one thing but having to factor in mercury contamination makes eating seafood a bigger ordeal than it has to be. Environmental Defense has done this research for you, though, so don't despair yet. Along with a handy pocket version, our seafood selector will tell you the best fish choices for you and the ocean. Check it out at http"//EnvironmentalDefense.org/seafood

Lauren Guite
Environmental Defense

finding the ways that work

by Lauren Guite at 12:25 PM on 25 Jan 2008

Correction

The seafood selector is at http://EnvironmentalDefense.org/seafood

Lauren Guite
Environmental Defense

finding the ways that work

by Lauren Guite at 12:27 PM on 25 Jan 2008

60 Minutes Piece on Bluefin Tuna processing

60 Minutes did a pretty decent story on the world wide trade of Bluefin tuna, and how a once traditional fishing method has become industrialized. The full segment can be seen online.

grist.org

by Jerome Woody at 1:02 PM on 25 Jan 2008

you're both right

Larger fish species, like the bluefin, tend to accumulate more methylmercury because they 1) are a longer lived species comparatively and 2) eat other fish (which have themselves accumulated the CH3Hg).

"Comparatively" is the operable word. It's true that bluefin species are in pretty dire straits the world over. They're overfished, and they're getting smaller and smaller (see the oft-cited "90% fished out" study published in Nature May 2003 for starters). However, they're still the largest tuna species by size, and they still feed at the top of the food chain. Thus, any bluefin will likely have more methylmercury than, for instance, sardines (which are much lower on the food chain) or a species whose diet consists solely of plants.

And if that isn't complicated enough, some fish stand still while others widely roam. Mercury concentrations, like some other pollutants (e.g., PCBs) can vary by geography as another comment noted. Bluefin are highly migratory, transversing wide areas of the ocean; for this reason, I would think it to be a pretty good indicator of the prevalence of methylmercury in our global oceans. It might be interesting to note whether the Southern Bluefin (in the Pacific Ocean) has more/less mercury on average than the Northern Bluefin (in the Atlantic and Mediterranean), but now we're splitting hairs.

Bottom line, bluefin is overfished and so, for those seafood lovers who care about their choices (shouldn't we all?), you probably want to avoid it regardless of the mercury issue!

Several groups have gotten savvy and developed seafood guides geared specifically to sushi lovers - see for example the NRDC guide, and the Monterey Bay Aquarium is apparently getting ready to launch its own version this year. The Environmental Defense seafood selector posted already does a good job of providing the eco- and health-conscious impacts. Consumer guides and cards are also becoming more prevalent in other countries - there are cards in the UK, Netherlands, Switzerland, Germany South Africa, Australia and now one in Hong Kong.

For the 411 on all of these cards by geography, visit www.seafoodchoices.org (and click on "Resources" to see the links)

Joey Brookhart
Seafood Choices Alliance - an international non-profit bridging the conservation and seafood communities

by joeybrookhart at 2:25 PM on 25 Jan 2008
[ Parent ]

the mercury cycle

I'd also like to add that many pseudo and self-styled "consumer advocacy" groups take issue with the Times story because, they claim, mercury in the ocean comes from natural sources. Let's review some facts, as established by government and scientific sources:

It's true that there are both natural (e.g, volcanoes) and man-made sources for mercury in the environment. Man-made sources include mining operations, coal-burning (as in, from power plants) and incineration of medical waste among others.

We've been burning fossil fuels for 150 years now, since the industrial revolution (and burning coal far longer).

Furthermore, our own US government acknowledges that "atmospheric deposition is the dominant source of mercury over most of the landscape." This covers both natural and man-made sources.

Something is... well something is just downright fishy with the claim that volcanoes are to blame for mercury in the ocean. It stands to reason that man-made sources would be contributing greatly to the accumulation of mercury currently in the environment.

And consumers, take note! Any organization that truly puts consumers' interests first would not raise this smoke screen or play such a 'blame game' - regardless of where the mercury comes from, the fact is that whether we like it or not mercury IS present in our seafood and environment. Just because it occurs naturally doesn't mean it's safe. Arsenic occurs naturally, too, but I wouldn't recommend chowing down.

At the same time, there are many wonderful seafood options to choose from that aren't contaminated with mercury - so neither should we stop eating seafood altogether.

A good overview of the natural (and unnatural) mercury cycle can be found at the USGS website - with a graphic for those so visually inclined.

USGS Mercury Fact Sheet
National Academy of Science, Institute of Medicine
US government websites, including FDA and EPA

Joey Brookhart
Seafood Choices Alliance

by joeybrookhart at 2:54 PM on 25 Jan 2008

Estimate your mercury intake

There's an easy way to estimate your mercury in-take from consuming seafood with a free on-line seafood mercury calculator.

Just go to http://www.GotMercury.com and list the fish you eat and your put in your weight.

by Mike Milne at 4:05 PM on 25 Jan 2008

stopped eating tuna years ago...

...but for the wrong reason, apparently.

I noticed that whenever I ate tuna (steaks), my tongue would get sore. I figured it was a Sign. Tuna had changed: there was a trace of something in modern tuna not good for me and my sore tongue was signalling that. I guess I have inadvertently saved myself from years of exposure to mercury.

It's not just tuna...

I have developed lots of sensitivities to consumer products that I had not had a problem with before in the last 20 years. In nearly every case, I have been able to track my sudden sensitivity to the product to a change in its contents. (I check out the contents on products I use on the EWG site nowadays -- Environmental Working Group.)

cmello

by cmello at 11:02 AM on 29 Jan 2008

ADVERTISING POLICY

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