canned tuna fish

World Tuna Day is May 2. It sounds kind of silly to have an observance day for a fish, but tuna plays a significant role in ocean ecosystems and global economics. Canned tuna is the third most commonly consumed seafood, and arguably the healthiest animal protein. Without careful management of this important species, your tuna sandwich may contribute to the collapse of ocean ecosystems. Do you know how sustainable your tuna is?

A Big Fish

There are about 40 species of tuna and tuna-like fish swimming in the Atlantic, Indian, and Pacific Oceans as well as the Mediterranean Sea. Most tuna is caught for two markets – canning and sushi. Light meat species like skipjack and yellowfin are primarily canned. Bluefin, ahi, and other red meat species are preferred for fresh fish markets. Tuna are apex predators that regulate populations of many other species, including squid, herring, and sardines.

Worth almost $10 billion per year, tuna accounts for 20% of the value of all marine capture fisheries and over 8% of all globally traded seafood. Approximately 7 million metric tons of tuna fish are caught each year. That amount threatens the long-term viability of tuna stocks. More than 96 countries are involved in tuna conservation and management. The Common Oceans ABNJ Program has reduced the number of major tuna stocks experiencing overfishing from 13 to five, reduced bycatch and pollution, and closed 18 vulnerable marine ecosystems to fishing.

Bluefin tuna Thunnus thynnus saltwater fish
Bluefin tuna

Dolphin Safe

For many of us, environmentally responsible shopping began with the dolphin-safe label on canned tuna. The label was never intended to guarantee sustainability. It only relates to minimizing dolphin bycatch (capture of non-target species). Dolphins are not the only unintentional casualties of tuna fishing, but there is a unique association between tuna and dolphins in certain fisheries that puts them at particular risk.

Dolphin safe label

Tuna companies use numerous dolphin-safe label variations, including the official Department of Commerce seal and Earth Island Institute’s logo. Dolphin safe labels have repeatedly been subject to criticism (most recently, the documentary Seaspiracy cast doubt on whether Earth Island Institute verifies claims). Although tuna fisheries are increasingly transparent, onboard human observer coverage and electronic monitoring systems are not universal, nor are they mandated anywhere in the world.

U.S. Dept. of Commerce Dolphin Safe label

For tuna to qualify as “dolphin-safe”, U.S. regulations require a written statement from the vessel captain certifying that fishing gear was not intentionally used to encircle dolphins and that no dolphins were killed or seriously injured in the process of catching the tuna. The Tuna Tracking and Verification Program spot checks tuna products in retail stores. It verifies the authenticity of the dolphin-safe label and the legal importation of the product into the United States. The brands that pass the check are listed online.


Dolphins are not the only bycatch of tuna fishing. Juvenile yellowfin and bigeye tuna school with adult skipjack. When juveniles are caught as bycatch, they never get to spawn, and stocks decline. In Fiji, sharks have presented a problem. To be sustainable, tuna fisheries must employ proven strategies to minimize all bycatch, not only dolphins.

Sustainable Tuna

As always, study the Monterey Bay Aquarium’s Seafood Watch recommendations. Avoid tuna caught using purse seines with floating objects (a.k.a. “FAD purse seines”). Currently, five of the 13 major tuna fisheries are overfished: these include all bluefin tuna; Indian Ocean yellowfin, bigeye (ahi), and albacore; and Atlantic Ocean bigeye (ahi).

Most tuna caught by U.S. fisheries are “Best Choices” or “Good Alternatives” except for Atlantic-caught bluefin and bigeye (ahi). Preferred fishing methods include harpoons, pole-and-line gears, or purse seines that don’t use floating objects (a.k.a. “non-FAD purse seines” or “FAD-free”).

Marine Stewardship Council Certification label

Look for the Marine Stewardship Council Certification. MSC is a third-party, science-based certification that includes standards for chain of custody, minimization of bycatch, and species population levels.

Reading Labels

If you can’t find MSC-certified tuna, how do you find the next best choice? Decoding tuna labels is tricky, but tuna should be labeled with the country of origin. Some tuna cans will identify the fishery or fishing method. Since canned tuna, like most chocolate, is not “single origin,” this may include a list such as “Indian Ocean (51,57) Pacific Ocean (71, 77, 61).” The numbers refer to United Nations area designations and can be found on the MSC “Track a Fishery” website. Chicken of the Sea allows you to trace your tuna based on codes on the can (although these searches sometimes come up blank).

That’s a lot of work for a can of tuna, but this is one situation where brand loyalty makes sense. Study the tuna available at your local grocery store. When you identify the most sustainable choice, stick with it. Then, like the certification systems, you only need to spot-check over time to ensure your tuna still meets standards.

Order Online

Most tuna sold in groceries is private-labeled, meaning the grocer applies their own brand, which makes finding a sustainable option harder. Here are three options we know to be among the most regulated sources of tuna. If they are not available locally, please consider ordering them using the links below. Earth911 will earn a small share of the sale to support our recycling search database.

By Gemma Alexander

Gemma Alexander has an M.S. in urban horticulture and a backyard filled with native plants. After working in a genetics laboratory and at a landfill, she now writes about the environment, the arts and family. See more of her writing here.