Your innocent tuna sandwich lunch raises an issue about which you may not be fully aware. The "dolphin-safe" label on your canned tuna raises questions about its true meaning and its impact on marine conservation.

One piece of information that stands out on a can of tuna is the "dolphin safe" label. But what does this label signify, and can one be sure of its truthfulness? According to a report by the United States Department of Agriculture, the "Dolphin-safe" label is a product of ongoing concerns about fishing procedures that harm dolphins. This problem mostly occurs in the eastern Pacific Ocean where dolphins and tuna cohabit. Fishermen encircle these dolphins using their nets to catch the tuna, a practice known as "setting on dolphins". This practice often results in dolphins getting entangled in the fishing nets leading to death or severe injuries.

In response to this, the U.S. ratified the Marine Mammal Protection Act in 1972, limiting the killing of dolphins by U.S. fishing operations, although foreign vessels are not restricted. In 1990, the U.S. also initiated the Dolphin Safe label law, which according to the International Marine Mammal Project, allows only a Dolphin Safe tuna label on tuna caught under conditions with no intentional harm or mortality to dolphins.

However, this label doesn't guarantee total safety for dolphins. As the National Oceanic and Atmospheric Administration (NOAA) pointed out, while a large portion of commercially sold canned tuna in the United States carry the dolphin-safe certification, certain federal regulations permit the sale of non-dolphin-safe tuna. This type of tuna may come from fishing operations where dolphins have been accidentally killed or seriously injured.

The question of whether dolphin populations are in danger is a complex one. The Inter-American Tropical Tuna Commission reports show a significant reduction in dolphin mortality, but other reports indicate that fishing activities still contribute to the deaths and serious injuries of over 650,000 marine mammals every year.

The authors of Net Loss: The Killing of Marine Mammals in Foreign Fisheries report, issued in 2014, provide a flicker of hope, stating that U.S. has managed to drop the figures of marine mammal bycatch by around 30% in 20 years, proving the possibility of turning this situation around. The hope lies in ensuring exporting nations comply with the same standards as domestic fisherman.

For consumers who wish to ensure they're making sustainable choices, tools like the Seafood Watch website can help them make informed decisions about what kind of canned tuna to buy. Labels like pole-caught, pole-and-line-caught, troll-caught, FAD-free, free school or school-caught indicate more sustainable practices. Websites like Save Dolphins also provide lists of dolphin-safe companies globally at savedolphins.eii.org.