Greenest of the Green: Sustainable, Low Mercury, Rich-in-Omega-3 Seafood

What seafood is sustainably caught or farmed? What fish and shellfish are safe to eat? What seafood is the healthiest? We get these questions from consumers all the time! So here’s our answer— a list of seafood recommendations called Greenest of the Green.

Greenest of the Green Infographic. Click on the image to enlarge it! Graphic by John Blanchard, 2015

Greenest of the Green Infographic. Click on the image to enlarge it!

These seafood species are:

rated green, which means sustainably caught or farmed (rated by either The Safina Center or by our partner, Monterey Bay Aquarium Seafood Watch®.)

a good source of healthy omega-3 fatty acids (at least 600 milligrams of omega-3s per 4 ounce serving. Thats 1/3 of the recommended weekly consumption level.) and

low in mercury (less than 0.1 part per million of mercury, which means they are safe for everyone to eat 2-3 times per week. YES, even pregnant or breastfeeding women can eat these species. They are safe for children too, but portions should be smaller.)

Seafood rated “Green” means that the fishing or farming practices are well-managed. And it means that the species was caught or farmed in a way that causes little harm to the environment or other wildlife. By choosing seafood from the “Green” list you are helping to ensure healthy oceans and fish populations for many generations to come. And sustainable practices help prevent needless killing of ocean wildlife (such as sea turtles, sharks, marine mammals, and seabirds).

By choosing seafood that has high omega-3s but low mercury, you help guarantee that you get the greatest nutritional benefits, while minimizing health risks.

You have probably heard that seafood is a healthy choice because it contains beneficial omega-3 fatty acids (as well as many other nutrients). Some of the benefits of omega-3s include reducing blood pressure, improving heart health and aiding in fetal brain development. But it is important to realize that not all seafood contains an abundance of omega-3s. In fact, several of the common seafood species that U.S. seafood consumers eat are actually low in omega-3s, including shrimp, tilapia, cod, catfish, and scallops.

It is also important to understand that eating seafood can come with health risks. When we eat seafood, we get a dose of mercury. And too much mercury is bad for us. Scientists have found that high levels of mercury in humans can cause brain and nervous system defects.  This is of particular concern in young growing children and for women who are pregnant, plan to become pregnant, or who are breastfeeding, since the mercury the mother consumes can affect the fetus or infant. Some seafood contains very high levels of mercury (typically large, predatory fish like tuna and swordfish), while other seafood contains very little mercury (smaller fish, lower on the food chain).

The purpose of our “Greenest of the Green” list is to make it easy to choose seafood that you can feel good about eating and that is good for you. So let’s take a look—from mussels to mackerel.


Farmed mussels and oysters are about as sustainable as it gets. They are grown in coastal waters in a similar manner to the way their wild counterparts grow. Raising them requires no food input or chemical use (antibiotics, pesticides, herbicides, fertilizers). Mussels and oysters feed by filtering phytoplankton (or free-swimming algae) right out of the water. And in doing so, they actually improve the water quality in coastal systems! Mussel and oyster beds can also provide structural habitat for other species and help prevent erosion of the shoreline.

Mussels and oysters may provide anywhere from 800-1,500 mg of omega-3s per 4 ounce serving. That’s on par with canned albacore tuna. But unlike albacore tuna, mussels and oysters have only minute levels of mercury.

SHOPPING TIP: Look for mussels and oysters grown in your local or regional area.


Wild Alaska salmon is the best source of salmon available to us. There are five species of Alaska salmon: Chinook (king), coho, pink, chum, and sockeye. Chinook and coho salmon have the highest omega-3s (1,000-2,000 mg per 4 ounce serving) but other salmon species are excellent sources of omega-3s too. Alaska salmon populations are relatively abundant and the fisheries are well-managed. This is not the case with many other wild salmon populations.

What about farmed salmon? Consider this: We export much of our healthy, delicious, sustainable salmon overseas and import questionable sources of farmed salmon from other countries. While some farmed salmon practices are improving, much of it remains unsustainable. Raising farmed salmon typically requires feeding the salmon wild fish. In fact, 2-3 tons of wild fish are used as feed for every 1 ton of salmon produced, which is not very efficient. Plus salmon feed often contains chemicals and antibiotics that are a threat to human health.

SHOPPING TIP: Next time you are looking for salmon, make sure to choose wild Alaska salmon (its well worth the few extra bucks!).



—U.S./Canada Pacific Sardine

—U.S. Atlantic Herring (Purse Seine) or Pacific Herring (California)

—U.S. Atlantic Mackerel (Purse Seine)

These small, low on the food chain fish are not very popular among U.S. seafood consumers. We typically export them to other countries that enjoy them more or we use them as bait to catch higher-on-the-food-chain-fish that have more mercury. Or we grind them up to use as fishmeal and fish oil to feed to farmed fish. This is unfortunate because consuming sardines, herring and mackerel directly could provide U.S. seafood consumers with a very high dose of omega-3s (1,000-2,000 mg per 4 ounce serving).

It is also important to note that these little fish play a very important role in ocean ecosystems, providing food for many large fish and other ocean animals. Because of this, we need to ensure we leave enough of these fish in the ocean to feed their predators. We are not advocating for catching more of these fish. Instead we are recommending that we use these fish in a much better, more direct way!

SHOPPING TIP: Try to find Atlantic Mackerel and Atlantic Herring caught by purse seines rather than mid-waters trawls. Purse seines are a more environmentally friendly catch method.

Next time you are planning to eat seafood, remember not all seafood is equal in terms of sustainability or health. Take a pass on the tuna and shrimp, which generally come from unsustainable sources and are not as healthy for you. Instead, try one of the “Greenest of the Green” species. You will be doing the oceans and yourself a favor!

–To find more sustainable seafood options check out our online seafood ratings. And to learn more about mercury in seafood, visit our Mercury in Seafood web section.

–For a printer-friendly version of our “Greenest of the Green” illustration, click here.

–For further information on omega-3s in seafood, see these sources: Harvard School of Public Health, U.S. Food and Drug Administration, and Environmental Working Group.





4 Comments on “Greenest of the Green: Sustainable, Low Mercury, Rich-in-Omega-3 Seafood

  1. Have you heard of Verlasso Salmon? It is produced (farmed) by AquaChile, in partnership with DuPont. Its feed is enriched with Omega 3 produced by fermenting sugar through a sophisticated fermentation process. The yeast used in the process replaces part of the wild fish protein in the feed and the omega 3 from this sustainable source allows most of the fish oil to be replaced by vegetable (canola) oil. This means that only 1 ton of wild fish is consumed to produce 1 ton of Verlasso Salmon.

    • Hi Eduardo. Thank you for your comment. I have heard of Verlasso salmon and I am aware of the efforts that have been made to reduce reliance on wild fish for this particular farmed salmon product. The Safina Center does not rate farmed species, but our partner, Monterey Bay Aquarium Seafood Watch, rates Verlasso farmed salmon as “yellow”, which means there are some concerns with the farming practices. One of the largest concerns is the use of antibiotics and pesticides, which can be harmful to the environment and human health. Wild-caught Alaska salmon is a healthier and more sustainable choice. I hope you will check out our website to learn more about choosing sustainable and healthy seafood!

  2. Many Alaskan Pink and Chum Salmon is from questionable sustainability. The “artificial production” of hundreds of millions of hatchery released salmon is causing major problems with our ecosystem and wild fish species. Hatchery fish in Alaska are mistakenly called “enhancing” wild stocks. In reality they are replacing these valuable pristine wild salmon through “artificial Production”

    When hatcheries release hundreds of millions of young salmon they out-compete the wild natural stocks… this is not “enhancement”. In Prince William Sound the Marine Stewardship Council refuses to certify those hatchery fish as sustainable. Big processors send over a third of these artificially produced Pink Salmon to China to be processed then sent back to us. Yert they are still labeled Wild Alaskan Salmon!

    Hatchery fish at this magnitude out compete replace and weaken wild salmon crab shrimp and herring. Hatchery fish “ranching” have become like invasive species. The oversight agencies like Alaska Department of Fish and Game are failing to uphold Alaskas strict Wild Salmon Policies designed to protect wild salmon stocks. They have been infiltrated by hatchery personnel and do not take into consideration the ecosystem. Purely money. Our wild native stocks need to be protected from these huge releases.

    Please google Problems with salmon hatcheries. There is a lot of literasture and research explaining this deep relatively unheard of problem affecting the health of the Pacific Ocean ecosystem.

    • Hi Nancy. Thank you for your comment and for raising concerns about the hatchery fish being used in some Alaska salmon fisheries. I am aware of these issues and it is something we are working on addressing. We partner with Monterey Bay Aquarium Seafood Watch, and they are working on new criteria standards for salmon fisheries that use hatchery production. The updated criteria will better account for the effects of hatchery production on wild populations. The targeted completion date for the new salmon criteria is the end of 2016.

      You are correct that the Marine Stewardship did not certify the Prince William Sound salmon fishery (the fishery withdrew from assessment), but all other Alaska salmon fisheries were certified by the Marine Stewardship Council. Currently, The Safina Center and Monterey Bay Aquarium Seafood Watch consider Alaska salmon to be “green”, but if this changes in the future we will update our website.

      I do believe that wild Alaska salmon is the best source of salmon available to us, and I completely agree that we need to ensure we are doing everything we can to protect this valuable wild resource and our ocean ecosystems.

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