The frozen shipment arrived in ordinary, white cardboard boxes. Grainy, black sketches on the labels depicted what anyone would identify as a catfish—long whiskers, fins, a wide flat head. Inside were stacks of pre-made fish filets. The filets were battered and fried. Then, they were thrown on a bed of golden hush-puppies and served hot as the crunchy delicacy that graces dinner tables across America—fried catfish.

But something about these filets seemed a little off. A latin word on the bottom of the box drew attention from a young, Tennessee restaurant cook. “It seemed strange,” he remembered thinking, “I’ve been around fishing my whole life and I had never seen catfish called by that. So I Googled it.”

That word was “pangasius hypopthalmus.” And the search result reveals something shocking about the US food industry—this fish is an endangered species.

Marketed in America as swai, the fish on your plate is native to the Mekong River of Southeast Asia. It’s a cousin of the famous Mekong giant catfish, which can grow to an astonishing 660lbs. And though swai are dwarfed by their giant cousins, they can still tip the scales at 97lbs, nearly double the size of the American channel cat.

Swai was once an abundant food source for people living on the Mekong. Now, it resides on the IUCN Redlist of endangered and threatened species.

So why are you being fed an endangered species? We talked to a food distribution sales rep to find out.

Turns out, the Mekong catfish are cheaper—much cheaper—than their yankee counterparts. Currently, a 15lb case of US-raised catfish from an American food distributor can cost restaurants as much as $82.00. That same 15lb box filled with pangasius is just $33.90.

According to our source, since pangasius were introduced to the US, “The price hasn’t moved five dollars. If anything, it may have dropped.” That amounts to big savings for the struggling dining business.

Food distributors are pushing the fish. Restaurant owners are buying it. And the public is eating it.

The IUCN Red List doesn’t automatically confer protection to any species, and the demand for swai is only growing.

Dr. Gary Burtle, an aquaculture specialist at the University of Georgia, says restaurants aren’t just marketing swai as catfish.

“Swai is a popular fish in the US due to its mild taste and firm texture,” states Burtle, who believes the fish is gaining in ground in the American food industry. “It has sometimes been sold as grouper or other fish that usually sell for a higher price than swai.” And recently, he says a market has started to emerge for the fish branded as itself.

“There is definitely a market now for swai as swai in the US.”

That’s grim news for the ecosystem of Southeast Asia, where swai have nearly vanished from their natural habitat.

Swai breading grounds in the Mekong River are characterized by sandy bottoms and large rock pools. The rock pools are under threat from blasting. Photo: Shannon O’Donnell, alittleadrift.com. Trade and fishing boats rest on the banks of the Mekong River near Luang Prabang, Laos. Photo: Shannon O’Donell, alittleadrift.com Despite regulations, swai are often sold as catfish or grouper in the U.S.

Where Did They Go?

9,000 miles from the mouth of the Mississippi River, the Mekong cuts a muddy swath through Laos, Thailand, Cambodia and Vietnam on her 2,700 mile journey to the South China Sea. Around the great river’s waters, a biologically diverse ecosystem second only to the Amazon Rainforest is adapting to pressures from the outside world: new damming projects from China, growing cities on her banks and exploitation of her wildlife.

An estimated 850 freshwater fish species live in the river, nearly four times the number found on the Mighty Mississippi. But the Mekong is home to dai-fishing, a method that casts large, gapping nets from flotillas spanning the river channel. The dai bring up some of the largest freshwater fish in the world—giant 150lb carp, freshwater stingrays up to 14ft in diameter as well as the iconic giant Mekong catfish.

Dai nets create a gauntlet for fish heading to and from their breading grounds, including swai, whose catch has reportedly decreased by 99% over the past 34 years.

Jeremy Wade knows these waters. As a journalist and television host of Animal Planet’s “River Monsters,” the 57-year old Brit has seen dai nets and fished for big cats on the Mekong. Wade says, thanks to over-fishing, swai and the giant Mekong catfish now share a similar fate, “Good numbers exist in commercial catch-and-release lakes,” he told us, “but there are very few left in the wild.”

Wade’s experience is backed by a 2001 study from the Mekong River Commission (MRC). That study pinpoints the natural breeding ground of swai to a sensitive, 60 mile-stretch of the river in Cambodia. And that breeding ground, according to the MRC, is under attack from rock blasting and overfishing.

It’s a problem that Cambodian authorities have tried but failed to control.

Thanks to this, if you’re looking for swai in the Mekong River, you won’t find them.

But you can find them—and the source of your dinner—nearly 100 miles south of their breading grounds in the Mekong Delta of Vietnam.

Americans may remember the Mekong Delta of the 1960s; a home to deadly jungle warfare and a stage for global politics.

But today’s Delta has changed. Here, you find a peaceful, burgeoning industry encapsulated by 23 square miles of pangasius-filled aquaculture ponds. 90% of the world’s pangasius are farmed here. They’re labeled as swai exported to dinner tables in the United States.

This aquaculture—fish farming—is something Jeremy Wade first witnessed in the region nearly 20 years ago in Thailand, and it’s fueled by international fish markets.

It’s fueled by restaurants in more than 130 markets worldwide. It’s fueled by months like June and July of 2011, when Vietnam alone exported more than $828 million worth of swai.

That’s big money. And it comes with big ecological risks.

Information from the World Wildlife Fund shows a 50-fold increase in swai aquaculture since the MRC study in 2001. In Vietnam, where safety regulations have come under scrutiny, the farms need careful regulation to avoid an ecological disaster. Native fish species near the farms are struggling as indigenous food sources get processed into swai-feed. Fish who escape from the farms can devastate local fish populations.

Swai farms have also raised health concerns among consumers. They are often thought to use toxic chemicals or contaminated water in their production process.

To combat consumer fear, Vietnam wants to certify 50% of swai production through the Aquaculture Stewardship Council by 2015; and trade companies are producing promotional videos of the farms, which provide insight into the life of a farmed pangasius.

Americans, for the most part, don’t seem to be aware that their food could be causing ecological harm on another continent.

Health risks, too, appear nearly unheard of. When FTR approached cooks and restaurant owners, many knew where their swai came from but were shocked to discover what it was. The most universal comment from restaurant employees was simply, “It’s cheap and it tastes like whatever you cook it in.”

Back at the University of Georgia, Dr. Burtle tells us the swai market has become so popular in the states that counterfeiting operations are now occurring.

The counterfeiting of a counterfeit—it’s another new industry that will affect fisheries around the globe. And it now seems certain that the ecological impact of pangasius hypophthalmus will not end at the shores of the South China Sea.