The fish that were in Mr. Khon’s pond are known internationally by their genus name
Pangasius
and locally as tra. If records from Vietnamese growers and government officials are to be believed, tra may be the most productive food fish on earth. Whereas an acre of codfish net pens will produce about ten thousand pounds of cod in a good year, that same acre in Vietnam will churn out half a million pounds of tra. This incredible tendency toward abundance has made the fish into the fourth most common aquaculture product in the world. From 50 million pounds in 1997, annual production has grown to well over 2.2
billion
pounds, a large portion of which goes to Europe. Production is still growing, and no one can quite say where the upper limit will be.
Even so, many suspicions were raised when tra first entered the European marketplace not long after the cod crises reached their peak in the late 1990s. And much of that suspicion emanates from how they were found and why they were first farmed. To illustrate, it’s worth repeating a joke my translator told me while we were motoring across the Mekong.
Question: “How do you tell a farmed fish from a wild fish?”
Answer: “The farmed fish is cross-eyed from staring up at the hole in the outhouse.”
The
Pangasius
genus, as well as quite a bit of freshwater aquaculture, can in fact trace its relationship with humans back to the privy. Tra were first introduced several hundred years ago into “latrine ponds”—stagnant bodies of water that peasant families maintained adjacent to the Mekong.
Pangasius
in these ponds fed on . . . well, let’s call it “decaying organic matter.” In addition to managing human waste, an added advantage of these fish was that when they were large enough, they could be sold to one of the many floating markets that line the banks of the Mekong all the way up to the Cambodian border.
This was the state of things for many years while Southeast Asia remained war-torn, isolated, and dependent upon subsistence food production. But beginning in the 1970s, ethnic Vietnamese living on Lake Tonlé Sap in Cambodia began intensively culturing fish in floating cages underneath their houseboats. They tried many different fish at first but through a process of elimination gradually arrived at
Pangasius.
“When farmers first collected samples for farming,” Dr. Nguyen Thanh Phuong, dean of the College of Aquaculture and Fisheries at Can Tho University, told me, “they would collect juvenile fish randomly. They didn’t even know what kind of fish they had in their jars. But when the oxygen ran out in the jars, all the fingerlings died. Except the
Pangasius.
”
There were two species of
Pangasius
that survived the jar test—
Pangasius bocourti,
known locally as basa (meaning “three balls,” because when cut lengthwise the flesh has three globes of fat distributed evenly around the spinal column), and
Pangasius hypophthalmus,
or tra. Initially it was basa that looked as though it would become the fish of choice. It adapted well to a variety of cooking methods and had a higher fat content than tra, which Southeast Asians value more than a dryer, flakier consistency.
But when ethnic Vietnamese began returning to Vietnam from Cambodia after the war between the two countries subsided, they started refining their aquaculture techniques. By the 1990s they gradually realized that tra took better to conditions in Vietnam
.
Unlike the lake environment in Cambodia, the Mekong Basin in Vietnam floods intensely every year. The entire flow of the Mekong is replaced during flood season, and stranded ponds are created adjacent to the main channel of the river. In these ponds it was found that conditions for raising fish could be better controlled than in the main stem of the Mekong. Pond culture didn’t have the disease problems and the water pH shifts that occasionally killed off fish in the open river. But the more desirable basa needed flowing water to prosper and didn’t do well in the ponds. Tra, on the contrary, seemed to thrive in stagnation. And while basa would die if too many fish were stocked in a pond, tra didn’t mind close quarters at all. The only thing tra would do differently in these high-density environments when oxygen levels in the water dwindled was to occasionally rise to the surface and stick their alien-looking mouths out of the water.
Tra, it turned out, can breathe air.
T
he idea of using a farmed freshwater fish to substitute for a wild, oceanic gadiform has been something that seafood marketers had been considering for some time. And in Europe, where cod is used in a fairly diverse range of cookery, slipping a slightly different fish into the culinary slot was possible. Sautéed or baked, tra can for not-so-discerning palates seem like cod or at least like Mrs. Kurlansky’s “fish.” But in the more classic American use of cod, battered and deep-fried, tra lack the “mouth feel” of cod. The flesh is slightly oilier, slightly more substantial, more like a bass than a cod. In fact, in the jumbled-up world of seafood import and export, Vietnamese tra occasionally gets labeled as that other Vietnamese catfish species, basa, and is then slotted into the culinary niche where bass should be. Back in Greece, the sea bass farmer Thanasis Frentzos lamented to me one evening that the Vietnamese could potentially cause the death of the Greek sea bass industry. “Sometimes they mean to write ‘basa’ on a crate of Vietnamese fish, and then someone decides to replace the
a
at the end with another
s,
and then you have ‘bass.’ ”
But tra are not the only superproductive freshwater fish out there. One class of fish in particular has arisen that is capable of assuming cod’s role as an industrial fish both in texture and in quantity. Whereas the tra’s key to abundance is tolerance for ultrahigh stocking densities, another fish, called the tilapia, has made a name for itself in the abundance arena through its reproductive strategies.
Unlike cod and pollock, which hurl millions of small eggs far and wide (“broadcast spawners,” in fisheries-science parlance), tilapia are of a family of fish called cichlids who have a tendency to be “mouth spawners.” They lay fewer eggs than cod, but females typically gather up those eggs, once fertilized, in their mouths and protect them until they have passed the fragile early-larval stage. As a result the average tilapia produces many more adults in the end than the average cod, and tilapia have an ability to greatly multiply their numbers exceedingly fast. It is a reproductive strategy suited much better to a twenty-first-century human-dominated world than is the random “trust in nature” approach utilized by cod and other gadiforms.
Tilapia, like tra, saw a gradual buildup in abundance in the second half of the twentieth century, but, as with tra, its initial expansion occurred primarily in the developing world. Most tilapia hail from the Nile but were first spread beyond Africa when the Japanese army blockaded Indonesia during World War II. At the time, Indonesian fish farmers relied on a fish called milkfish for their aquaculture farms, but with the blockade they couldn’t access the milkfish broodstock, which became stranded behind enemy lines. American forces were able to get a few stray tilapia to the Indonesians, and they soon found that tilapia grew nearly twice as fast as milkfish.
After the war, when the Peace Corps was born and the United States Agency for International Development implemented hunger-relief programs in postcolonial countries around the world, tilapia were seen as a solution to the world protein deficit. Not only did they reproduce with great abandon and without any help from humans, they technically required no food whatsoever. Tilapia, like tra in their native state, are filter feeders, able to live solely off elements of human waste, algae, and other microscopic plankton. So with tilapia, poor farmers, whose only resource besides land might be a stagnant patch of muddy water, suddenly had the chance to add protein to their diet with very little effort.
Early Peace Corps volunteers became unabashed tilapia enthusiasts. And when they left the Peace Corps and moved into the for-profit world, they saw an opportunity to turn the fish into a moneymaker. “It was like this miracle fish,” a former Peace Corps worker-turned-tilapia entrepreneur named Mike Picchietti told me recently. “We thought we could make this fish into a major business. But it ended up taking a long, long time.”
Until the 1990s both tra and tilapia remained “development” fish—Third World menu items that would have no real market impact in Europe or the United States. Partly this was because the fish had no brand identity in First World nations. (One aquaculturist told me that when he first heard the word “tilapia,” he thought it was a stomach disease.) But another major factor had to do with a phenomenon that plagues all freshwater-fish farmers, something known as “off-flavor.” Off-flavor occurs in stagnant fresh water when certain varieties of blue-green algae bloom and emit a compound called geosim, from the Greek
geo,
meaning “earth.” Fish inhabiting these blooms temporarily take on the taste of geosim, a harmless but earthy flavor that most diners find unpleasantly muddy. In fact, off-flavor is one of the key reasons that many consumers have stayed resistant to farmed fish. Any fish can develop off-flavor, though freshwater species are more susceptible to it. Mastering the problem turns out to be the key to producing a widely acceptable product.
In the 1990s both tilapia and tra went through a revolution that transformed them from Third World to First World table fare. By 1994, tilapia, with their incredible fertility, had spread to Latin America. In a few instances, they were associated with the cocaine trade. South American Indians farming coca leaves in Colombia also came to farm tilapia. And while the coca crop was of paramount importance to drug lords operating in the region, tilapia could also serve their purposes. With millions of dollars of excess cash that needed to be laundered, they saw in tilapia an opportunity both to improve the lives of their growers and also to cleanse their drug take. There was an added benefit to coca growers. As one fish farmer told me, asking not to be identified by name for obvious reasons, “If you put a Gel-Pak of cocaine in a crate full of tilapia fillets, can a drug-sniffing dog find it? Nope.”
What both tilapia farmers in Latin America and tra farmers and Vietnam realized was that if they managed to secure a constant supply of clear, flowing water, devoid of algal blooms, and if they fed their fish a diet of corn and soy instead of letting them subsist on waste and algae, they were able to control the off-flavor in their product. Instead of tasting like mud, tilapia and tra, by the late 1990s, tasted like nothing.
“The thing people like about tilapia,” Picchietti told me, “is that it doesn’t taste like fish. We often like to say it’s the unfishy fish.” Which, if the example of cod is considered, might ultimately be what the world is looking for. In twenty years tilapia production has tripled from 2 billion to nearly 6 billion pounds annually and is anticipated to grow another 10 percent in the next year alone. It is a naturally abundant, flavor-neutral product that is versatile in the kitchen and easy on the wallet. Indeed, these very qualities (or lack of qualities) have now made tilapia scale the highest heights of cheap food. After developing a patent-pending marinade that gives tilapia a “taste like pollock,” HQ Sustainable Maritime Industries, a tilapia grower whose very robust production comes primarily from China, has concluded successful negotiations with one of the largest fast-food chains in the world. Although I cannot name the chain in these pages, suffice it to say it is likely that all of us will have the option of eating a fast-food tilapia sandwich in the not-too-distant future.
T
he Aquaculture Dialogues is a series of eight working groups convened by the World Wildlife Fund with the goal of creating standards for the fish-farming industry. In 2008 I sat in on a session of the Tilapia Dialogue in Washington, D.C. Early on in the discussion a motion was put before the gathered assembly of tilapia farmers, nonprofit organizations, various and sundry scientists and onlookers like myself that from here forward, people in the tilapia industry should “seek to prevent the global spread of tilapia beyond its already established range.” A chuckle rippled around the room. “Too late!” a farmer from Pennsylvania said with a laugh. “Already happened,” said another.
It is one of the great ironies of the modern-day seafood world that humanity is desperately trying to figure out a way to boost the numbers of one fish, cod, and, as an indirect result of the cod shortages, we are doing everything we can to keep another fish, tilapia, from multiplying and spreading too quickly. Tilapia is overstepping its ecological bounds in nearly every corner of the globe and is considered a most invasive species. The fish live mostly in fresh water, and freshwater bodies around the world are increasingly dominated by them. Tilapia can also adapt to more-saline conditions than most freshwater fish can tolerate, and as a result often find their way into brackish waters near river mouths.
There is now an active effort to try to put the biological tilapia genie back in the bottle. In Australia a $16 million campaign has been launched to keep tilapia out of the island continent. There are considerable obstacles. Chinese immigrants consider it good luck before sitting down to a meal of fish to release a live fish into the water. Because they are so hardy and require so little oxygen, tilapia are perfectly suited to take advantage of this cultural tradition. They are often delivered live to Asian markets throughout the United States, Europe, and Oceania, and when they arrive, it is not uncommon for Chinese immigrants to drop one or two into a local lake or stream. From there it is just a matter of time before they proliferate at frightening speed and reach a biological maximum.
In the United States and Europe, the ultimate range of tilapia has been restricted by a climatological zone. Tilapia die if water temperatures fall below fifty degrees Fahrenheit for more than a month, and so even when they are purposefully grown north of the Deep South in the summer, they die off when winter sets in. But winters are getting milder and shorter, and with each successively warm year tilapia inch a little bit farther north.