Tuna swim faster than almost any other fish in the ocean—but not fast enough to escape the fishing fleets and farming of humanity. As a result of global demand, the giants of the sea known as bluefin tuna are shrinking in size, or in some cases disappearing altogether. In fact, off the eastern coast of Nova Scotia, where enormous bluefin tuna used to be visible deep beneath the waves, populations have dropped by 90 percent, according to the consortium of countries that make up the International Commission for the Conservation of Atlantic Tunas.
This week, the consortium’s Pacific counterpart—the Inter-American Tropical Tuna Commission—is meeting in Panama City, Panama, to determine the fate of the yellowfin tuna, known as hamachi to sushi connoisseurs and chunk light to American grocery shoppers. Although the fish are not considered threatened, the average size of yellowfins caught has begun to shrink, in the first sign of a crashing population. Environmental groups such as the World Wildlife Fund are calling on the commission to adopt closures to protect the fish and allow stocks to recover.
Yet the 16 countries that make up the commission have found it difficult to agree on conservation measures due to a lack of consensus. And some nations, such as Peru and Japan, are seeking to increase the size of their fishing fleets.
Scientific American's David Biello spoke with Richard Ellis, author of Tuna: A Love Story, about the problems facing the chicken of the sea.
Scientific American: In light of the meeting this week, what is happening with the yellowfin tuna?
Richard Ellis: It's a popular food fish. It is probably, in [the U.S.], the most popular tuna for grilling and for sashimi. Yellowfin is what you get when you order tuna sashimi or sushi in most Japanese restaurants. It is heavily fished... It is yellowfin that is at the top of most lists of concern for fish because it's [the] most heavily fished.
Is it endangered?
They don't know. One of the real problems with ... endangered species, [in] regards [to] fish, is that it's very hard to count them. Usually the count is done via decreased catch. Why is the catch going down? Maybe there aren't many left. But doing an actual survey is virtually impossible. From fishery records, however, primarily Japanese longline [fishing] records, scientists [have] realized that about 90 percent of all big predatory fishes are gone. What they are fishing is the remaining 10 percent. That goes for every large predatory fish: sharks, tuna, sailfish, cod... It's only through fishing that we have any idea how many fish are out there.
What is happening to the tuna generally?
The biggest and most spectacular [tuna] is the bluefin, and it is also the one that is most in trouble. But there are many smaller species that are hunted very strenuously, [such as yellowfin, which are] in many cases overfished and in many cases they're not. Tuna in a can, for example, labeled white meat tuna, it's from a fish called an albacore. It's the only tuna that can be labeled white meat tuna and it's not in trouble. Light meat tuna is skipjack: it's the most popular food fish in the world, just think of the cans of tuna in the world. And it's also not in trouble... But the ne plus ultra of tuna is the bluefin and it's in trouble because it is probably the favorite food of the Japanese.
What is so special about the bluefin tuna?
The bluefin tuna is one of the fastest, largest, smartest, most highly evolved fish on Earth, and it undertakes epic migrations... Admire it as I do, after all my book is called Tuna: A Love Story, I still eat it. And other people love it, not because it's fast or beautiful or intelligent, but rather because they like to see it on a plate...