From wild-caught to dolphin-safe: Here are the different types of canned tuna and what their labels mean

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Terms like "wild-caught" and "MSC-certified" are all over canned tuna labels, but what exactly do they mean? (Photo: Getty Creative)

For most, canned tuna is a pantry staple. This non-perishable canned good not only has a long shelf-life, but it's also great to have on hand for emergencies, like when there's no electricity or access to a refrigerator. But how does the canned tuna we consume make it onto grocery store shelves?

According to the National Fisheries Institute, canned tuna is the second-most popular seafood product in the U.S., behind shrimp. Americans eat about one billion pounds of canned and pouched tuna each year, and at least 88% of U.S. households consume it, with almost half the households in the U.S. opening a can at least monthly.

"Canned tuna is a good food," Richard LaMarita, a chef-instructor at the Institute of Culinary Education, tells Yahoo Life. "It's convenient, easily accessible and in no time, you can come up with a great tuna salad, put it on toast and enjoy a great lunch."

Despite the volume consumed each year, many still do not know how canned tuna is caught and what the words on canned tuna labels — like "wild caught" and "pole and line caught" — mean. To make sense of the labels seen on grocery store shelves, Yahoo Life chatted with experts to find out what to look for next time you opt for a can of this popular protein-packed food.

How is canned tuna caught?

When it comes to catching canned tuna, sustainable practices are important for maintaining aquatic ecosystems and keeping the fish industry thriving. However, Bill Carvalho, founder and president of Wild Planet Foods, says not everyone in the commercial fishing industry makes sustainability a priority.

"Unfortunately, overfishing and wasteful fishing methods plague the industry and are leading to a depletion of fish stocks and negative environmental impacts," says Carvalho. "Large industrial fishing organizations utilize fish aggregating devices (F.A.D.s) that attract a wide variety of sea life to an area and then indiscriminately scoop them up in a purse seine net. Too often, the non-targeted fish are left to die and then tossed overboard as waste."

However, there are more sustainable methods like "pole and line" fishing that can be used to catch tuna. For this method, skilled fishermen stand on a boat and utilize one pole and one line with the intention of selectively catching tuna. When a school of tuna is located, the fishermen use bait to bring younger, migratory tuna to the surface of the water. They then cast their line into the ocean where fish are attracted to the feathered, barbless lure. When the tuna bites, the fishermen quickly pull the fish out of the water one at a time, onto the boat, where they easily release themselves from the hook.

Why is this method best? "Catching one fish at a time rather than casting a giant net which captures unwanted species not only helps protect fish populations, but also eliminates large volumes of wasted seafood caught in commercial fishing nets," says Carvalho.

What's inside canned tuna?

Which types of fish can potentially make it into a tuna can? "There are over 15 species — skipjack, yellowfin, bluefin, bigeye and albacore for example — of saltwater fish that can be labeled tuna," says LaMarita. "Usually, canned tuna can be a mix of species or, when it is cooked several times over as it is for canned tuna, it is harder to distinguish what the actual species of fish is."

For many foods, canned tuna included, it's up to the packaging to tell consumers what's inside. Lisa McManus, executive editor at America's Test Kitchen Reviews, shares the meanings of some of the common terms seen on a packages of canned tuna, from "dolphin-safe" to "troll-caught."

Terms to look for:

MSC-Certified: Marine Stewardship Council–certified products must meet rigorous standards for sustainable fishing practices, such as limiting bycatch (unwanted fish), avoiding overfishing and protecting marine environments.

Pole and Line Caught: This tuna is caught one-by-one on traditional fishing lines, each held by a person. This claim often appears on cans of tuna and is considered one of the most sustainable methods because it leads to no destructive bycatch of unwanted species.

Dolphin-Safe: This tuna is harvested using fishing methods that are not harmful to dolphins. This claim frequently appears on cans of tuna, but there are disputes about how meaningful it is and whether it is widely enforced

Troll-Caught: Not often seen on labels, this refers to a system whereby many baited individual fishing lines are attached to a boat and dragged slowly through the water. The practice is similar to pole caught, but without individual fishermen holding the lines.

Terms to avoid:

Wild-Caught: While this looks like a good claim to make, nearly 99% of tuna is wild-caught; tuna farming is in its infancy and mostly focuses on bluefin tuna eaten fresh, not canned.

Purse Seine: A cylindrical net that can be closed at the bottom to trap a school of fish drawn to a spot by bait. This method is criticized for the high amount of destructive bycatch it can yield, along with the intended tuna. This common method is not usually mentioned on cans, and where no other method is listed, is likely how the fish were caught.

F.A.D.: Fish Aggregating Devices are man-made floating objects made to resemble floating seaweed and logs that attract fish, which are then netted. F.A.D.s are criticized by environmental groups for a high amount of destructive bycatch, as sea turtles and other species that are not tuna are swept up with the tuna and killed. This method is not usually mentioned on cans, and where no other method is listed, is another likely way the fish were caught.

While it's normal to think your one can of tuna will not have an impact on the environment, experts say that's not the case. Consumers can each do their part, extending more caution the next time they're at the grocery store.

"Consumers can seek out brands that catch tuna in sustainable ways that don't damage a lot of other species along the way or overfish to the point of damaging the tuna population," says McManus, "or that are not harmful to marine environments."

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