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For the conscious consumer, a variety of species and fishing methods can muddy the waters, but there’s no need to swear it off altogether.
The Old Man and the Sea, Hemingway’s fable of man versus fish, could have been written about an Atlantic bluefin tuna. These apex predators grow about 7 feet long and weigh in at about 500 pounds. The biggest on record, caught off Nova Scotia, an area known for behemoth bluefin, was 12.6 feet long and weighed nearly 1,500 pounds. If Hemingway’s lone hero had hooked that one, there wouldn’t have been much of a fight to write about. In 1934, six men in Nova Scotia took turns fighting a massive tuna for 62 hours.
Bluefin tuna have longer lifespans than most fish — about 15 years, although the biggest can live as long as 50 years. Their relatively long development equips them with an efficient circulatory system and a ferocious muscular strength that makes them one of the ocean’s fastest swimmers and a frightening predator for sardines, mackerel, eel, squid, and more.
But this strength is no match for increasingly destructive fishing methods. In 2016, the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean found that overfishing had decimated Pacific bluefin tuna stocks by 97.4%. Since then, Pacific stocks have rebounded somewhat, exceeding international targets, but their precarious status raises questions about the ethics of eating bluefin.
Luckily for fish lovers, bluefin isn’t the only edible tuna. Five tuna species are typically consumed as food, which can cause confusion at the fish counter. Throw in a slew of fishing methods, each with their own environmental impacts, and choosing sustainable tuna can become downright daunting. Here are the basics.
Americans eat an average of 2.2 pounds of tuna every year, but Seafood Watch, a Monterey Bay Aquarium watchdog that monitors and rates seafood sustainability, has deemed that more than 50% of the most popular kinds of tuna are unsustainable.
More than a dozen species of tuna live in oceans around the world. They’ve evolved an ability, unique among fish, to regulate their body temperature, which means they can thrive in warm and cool waters, from equatorial to subpolar latitudes. They must swim constantly to oxygenate their blood and migrate often.
Skipjack tuna (Katsuwonus pelamis), often sold as “chunk light” or “light” tuna (or cat food), swim in schools and are the smallest commercial species, growing to between 15 and 30 inches long. Found mainly in tropical waters in the Atlantic, Indian, and Pacific oceans, skipjack comprised about 57% of the global tuna harvest in 2023, and their global populations are healthy.
Because they sometimes form schools around floating objects, they’re a prime target for fish aggregating devices, or FADs. These manmade objects are deployed in deep water to attract pelagic species like tuna, billfish, and mahi-mahi. Their ropes and lines collect marine vegetation, crustaceans, and mollusks, which in turn attract bigger and bigger fish. Electronic FADs transmit their locations and information about how many fish are nearby. Fishermen, following the data, can then catch target species with seines (nets), hooks, or longlines. While some FADs are anchored, others float freely. If they drift out of legal fishing areas, they’re often deactivated — and become “ghost nets,” litter that entangles coral reefs and sea life and washes up on distant islands.
Seafood Watch recommends avoiding imported skipjack caught with FAD-equipped purse seines due to concerns about bycatch and ineffective fishery management, especially in the Indian Ocean. Instead, Seafood Watch recommends domestic Pacific skipjack and Atlantic or Pacific skipjack caught with pole-and-lines or trolling lines. Skipjack caught in the Pacific with dolphin-set purse seines gets the go-ahead, too.
Albacore tuna (Thunnus alalunga) live in temperate and tropical waters in all of the world’s oceans and made up about 4% of 2023’s global tuna catch. Slightly larger than skipjack, with paler and more delicate meat, albacore tends to be firm and fishy. It’s another prime candidate for canning and is often sold as “white” tuna. The Pacific and Atlantic albacore fisheries are in good shape. That’s not the case in the overfished Indian Ocean. Steer clear of imported and longline-caught albacore, particularly from the Indian Ocean. Seafood Watch recommends albacore caught with pole-and-lines or trolling lines in U.S. Atlantic and Pacific fisheries.
Compared to skipjack and albacore, yellowfin tuna (Thunnus albacares) are likewise found in tropical and temperate waters around the world but they’re slightly bigger and more expensive. Firm and meaty with a mild flavor, yellowfin is popular grilled or in sushi and sashimi. Both bigeye tuna and yellowfin are also known as ahi. (Sushi connoisseurs may want to consult Seafood Watch’s handy print-and-fold sushi guide.) As with other varieties, stocks are healthy in the Atlantic and Pacific but not in the Indian Ocean. Follow the same guidelines as with albacore — avoid fish sourced from the Indian Ocean and imports caught with drifting longlines or in the western central Pacific with FADs.
Luckily for fish lovers, bluefin isn’t the only edible tuna. Five tuna species are typically consumed as food, which can cause confusion at the fish counter.
True to their name, bigeye tuna (Thunnus obesus) boast sizable lookers — and price tags. The tropical and subtropical species can grow up to 10 feet long and has rich, fatty meat, making it a sushi star. It’s typically sold fresh rather than preserved in cans or pouches. Many seafood sustainability guides recommend that consumers opt for other species because of the high likelihood that the bigeye in restaurants and supermarkets come from unsustainable fisheries. In 2010, Greenpeace put bigeye on its seafood red list. They’re holding out in the Pacific but are overfished in the Atlantic and Indian oceans. Seafood Watch gives the all-clear to Atlantic and Pacific bigeye caught with pole-and-lines or trolling lines, or caught in the eastern Pacific with FAD-equipped purse seines, along with domestic bigeye caught in the Pacific — but warns against domestic bigeye caught in the Atlantic with drifting longlines. That’s a lot to keep in mind at the seafood counter. It may be easier to simply avoid bigeye altogether.
The same advice holds for Atlantic, Pacific, and Southern bluefin tuna (Thunnus thynnus), the king of tuna. Bluefin are severely overfished around the world, and it’s best to choose something else. In Seafood Watch’s estimation, the only acceptable bluefin comes from U.S. Pacific fisheries, caught with pole-and-lines, or from California and Mexico with FAD-free purse seines, and even those don’t get the group’s most sustainable green rating. Farmed bluefin isn’t a safe alternative because they’re sourced from the wild. Keep an eye out for kuro maguro or hon maguro on sushi menus — those refer to bluefin.
Got all that? Even with guidance, tuna purchases can be confounding. Your best course may be to verify sourcing and fishing methods, find retailers and brands you can trust, then sticking with those. If you’re buying canned, check the label for terms like pole-caught, pole-and-line, troll-caught, FAD-free, free school, or school-caught, which indicate more sustainable harvesting practices. Brands like American Tuna, Fishing Vessel St. Jude, Ocean Naturals, Safe Catch, Wild Planet, and Whole Foods 365 sell sustainable options. Beware of terms like dolphin-safe, which doesn’t guarantee that the tuna is sustainable, and line-caught, which can refer to harmful longlines. You can bypass the can-reading at retailers like Whole Foods and mid-Atlantic chain MOM’s Organic Market, which have sustainable-seafood policies that encompass their canned and pouched tuna. “Look for American tuna,” says Corbett Nash, outreach manager at Seafood Watch. “The biggest things you want to look for on that can is ‘troll’ or ‘pole-and-line.’ Those mean bycatch is reduced.” FADs and purse seines, on the other hand, increase the likelihood of harmful bycatch and other destructive effects. Be sure to ask at restaurants about their sourcing, and when you inevitably forget the finer points, refer to Seafood Watch’s buying guide or Greenpeace’s tuna retailer scorecard.
In The Old Man and the Sea, the fight between Hemingway’s hero, Santiago, and the giant marlin he hooks destroys them both. Global tuna demand is likewise taking a catastrophic toll. By taking the time to decipher and pursue sustainable options, you can help chalk up wins for fisheries, ocean health, and all types of tuna — but especially the beleaguered bluefin, one of the undisputed lords of the sea.
Key Takeaways
- Prioritize sustainable fishing methods. When buying canned tuna, look for labels that explicitly state “pole-caught,” “pole-and-line,” “troll-caught,” “FAD-free,” “free school,” or “school-caught.”
- Try something other than bluefin and bigeye tuna. Bluefin tuna is severely overfished globally, so it is best to choose something else. Many sustainability guides also recommend avoiding bigeye tuna because of the high likelihood that the fish comes from unsustainable fisheries.
- Pay attention to origin. For skipjack, albacore, and yellowfin tuna, stocks are often overfished in the Indian Ocean, so steer clear of fish imported from that region.
- Stick to trusted retailers and brands. Since tuna purchases can be confusing, your best bet may be to find retailers (like Whole Foods or MOM’s Organic Market) and brands that you trust and that have strong sustainable-seafood policies. If buying fresh or at a restaurant, be sure to ask about their sourcing.
- Beware of misleading terms on labels. Vague terms like “dolphin-safe” do not guarantee that the tuna is sustainable, and “line-caught” can refer to harmful longlines.
