The Dirty Truth Behind America's Obsession With Shrimp

Most Americans don't know the ugly backstory of the shrimp on their plates: destroyed mangrove forests, toxic sludge, and displaced lives.

April 1, 2011  |  

Shrimp and mangroves. Mangroves and shrimp. The two are intertwined, ecologically and economically. They are like a pair of orbiting stars, though one shines at the expense of the other. The bitter irony is that without mangroves, there would be no shrimp. Mangroves are the natural nurseries of the shrimp species that are farmed commercially, just as they are for so many other marine creatures. In the wild, shrimp begin their lives in offshore waters, where the adults spawn. Then, carried inshore by currents, and perhaps aided by their own swimming, the larvae take up residence in sheltered inshore habitats where mangroves flourish. There, living and feeding in the shelter of the tangled limbs of the mangrove forest, they grow and molt until they are ready to migrate back out to sea.

Technology has short-circuited this ecological connection. Industrial shrimp hatcheries have taken the place of mangrove nurseries. From the viewpoint of commercial shrimp farming, mangroves are superfluous. And that is exactly what they have become on the ground. In most developing countries, it is not possible to visit mangroves without seeing the hobnailed bootprint of a rapacious industry. How did aquaculture come to be such a destructive force, and shrimp the mangroves' nemesis?

Let's go back to the origins of the industry. The oldest known guide to aquaculture was written in 475 BC and consists of advice from a Chinese administrator named Fan-Li to the ruler of a neighboring kingdom on how to get rich by culturing carp. The document contains information about pond size, stocking rates, nutrition, and predator control. (To ward off fish-stealing birds, writes Fan-Li, turtles should be deployed as "heavenly guards.") Follow his instructions, Fan-Li tells the king, and by the third year "the increase in income is countless." Aquaculture is pitched as a get-rich-quick scheme--just as it is today.

Remarkably, by the time Fan-Li's paean to piscicultural profits came to be written the Chinese had already been practicing aquaculture for 2,000 years, and today China is the world leader, responsible for two-thirds of global production. The industry has come a long way from the rearing of carp in ornamental ponds. Now dozens of freshwater and marine species are farmed, from tilapia to tuna, scallops to seahorses. Geneticists produce superhybrid varieties that are disease-resistant and have faster growth rates, higher nutritional value, shorter life cycles (in the case of shellfish), and longer harvest periods (in the case of edible seaweeds) than their wild progenitors. Oceanographers scour the seas for microbes with potential for use as feedstocks, and aquaculture entrepreneurs design multistory "pondominiums" -- whole cities of sea creatures.

Shrimp aquaculture (more accurately called mariculture, because most farmed shrimp are marine species) has a somewhat shorter history. It was not until the early 1960s that Japanese ichthyologist Motosaku Fujinaga, after 30 years of painstaking research and experimentation, succeeded in raising commercial quantities of the esteemed kuruma sushi shrimp, Penaeus japonicus, in captivity. Word of the breakthrough spread quickly, and Fujinaga's success was followed by further breakthroughs in hatchery techniques, feeding, and disease control. By the 1970s, farmed shrimp -- "pink gold" -- was the star of the Blue Revolution, the anticipated great leap forward in aquatic productivity that many hoped would rival the Green Revolution's surge in grain yields in the 1950s.

That dream has been realized. From contributing 8 percent of the world's seafood harvest in 1975, aquaculture now provides more than half. "Aquaculture ranks as a phenomenal story in global food production," says Jurgenne Primavera, a Filipino fisheries scientist who was named one of Time magazine's "heroes of the environment" in 2008.

Part of the commercial success of shrimp aquaculture arises from Primavera's own work on Penaeus monodon, the giant tiger shrimp, largest of the world's 2,000-some shrimp species, which attains lengths of more than 30 centimeters (12 inches) and a body weight of more than half a kilogram. In the 1970s, Primavera's groundbreaking studies on the growth and survival of tiger shrimp in the Philippines helped make P. monodon the most widely cultivated shrimp in the world.

It was only later that she realized she had a tiger by the tail. The industry she helped foster has bitten her own country hard, wreaking destruction on the mangroves that are a source of food and livelihood for millions of coastal dwellers. Between 1950 and 1990 the Philippines lost 66 percent of its mangrove forests. More than half of the losses were through conversion to shrimp ponds. A similar trail of destruction followed shrimp farming in Thailand and Vietnam.

"All across Southeast and South Asia, residential, agricultural and forest lands are being converted into shrimp farms," Primavera wrote in 2005. "Indian fishing communities who once were called pattapuraja, meaning kings of the coastline, now find themselves refugees of aquaculture development."

The damage didn't stop in Asia. As developing countries in the Americas and Africa staked their claim in the pink-gold bonanza, the mangrove decline accelerated. In 2001, it was estimated that aquaculture had been responsible for 52 percent of global mangrove loss, with shrimp farming alone accounting for 38 percent of the destruction.

The conflict between mangroves and shrimp farming arose from a simple geographical fact: prime pond location was in the shore zone occupied by mangroves. In its simplest form, shrimp farming involves building ponds in the upper intertidal zone, where mangroves live, and letting the tide fill them with water. This was the style of shrimp farming I witnessed in the Sundarbans. 

With the moon as a pump and the sea as a hatchery, there is little cost involved, but productivity is low.

As aquafarmers ratchet up the intensity, stocking their ponds with hatchery-spawned larvae, growing them with high-energy feeds and supplements, filtering, circulating, and aerating the water, and countering disease outbreaks with antibiotics, proximity to the sea, though not essential, is still an asset. Seawater can be pumped into the ponds from a short distance away, and transport of feeds and harvested shrimp by boat is practical and economical.

For the pioneering shrimp farmers of Asia and Latin America, there was an even more attractive reason to site ponds in mangroves: the land was available and cheap to lease. In most countries, tidal lands are state owned and cannot be bought or sold. Shrimp entrepreneurs found that governments were willing to grant them concessionary use of this land for peppercorn rentals. Governments were keen on shrimp because they were a desirable export commodity that brought in valuable foreign exchange. The World Bank and the International Monetary Fund promoted aquaculture because it helped developing nations diversify their exports and spread risk, and it kept the wheels of debt repayment turning. During the 1980s and '90s the World Bank, IMF, and other international lenders were enthusiastic backers of shrimp farming in the Third World.

The fact that mangroves occupied the preferred shrimp zone was inconvenient but of no great concern. The land was considered underutilized, and mangroves were easily removed. Predictably, any concerns about environmental damage were quickly overwhelmed by the irresistible force of commerce. The situation wasn't helped by the fact that jurisdiction over mangroves was often held by two or more government agencies with differing agendas. In the Philippines, for example, the mandate of the Department of Environment and Natural Resources was to protect and manage mangroves, while that of the Department of Agriculture was to promote aquaculture -- at the expense of mangroves.

And so began two decades of concerted deforestation. Mangroves fell to ax, match and bulldozer at a rate of between 1 and 2 percent per year -- the same rate at which inland rainforests were being felled to make way for cattle and soybeans. It was a devastating double whammy for the forests of the Third World: slash-and-burn agriculture in the terrestrial rainforests, bulldoze-and-fill aquaculture in the mangroves. But while rainforest destruction quickly attracted urgent and vociferous opposition, the removal of mangroves was off the public radar. For most people, it still is.

Perhaps the most ecologically grotesque aspect of the shrimp industry in its early days was the practice of farmers abandoning their ponds after a few years and moving to new sites. A pond dug on a freshly felled mangrove forest receives a built-in nutrient subsidy in the form of organic matter stored in the soil. The nutrients boost plankton growth and increase pond productivity. But after a few years, the nutrients are exhausted and productivity declines. 

Wastes, chemical treatments, and unconsumed shrimp feed build up a contaminating sludge on the bottom of ponds, and if a viral disease should break out, future crops will be at risk in the affected ponds. Such problems can be solved with careful pond management, but with mangrove land undervalued, concessions cheap, and governments supportive or compliant, many shrimp farmers found it easier to cut and run than to stay and manage.

Pond abandonment is a double tragedy for the environment. Not only are additional mangroves sacrificed in the construction of new ponds, but the old pond land, rather than becoming available for agriculture or for replanting in mangroves, often ends up a toxic dead-end. Ponds can be successfully rehabilitated, but it takes time and money. So far, the shrimp industry has shown little inclination to address, let alone repair, past damages.

Aquaculture is often linked to the issue of human food security, and rightly so. As capture fisheries continue to decline, aquaculture has the potential to meet the shortfall. This has always been one of the tenets of the Blue Revolution. But shrimp aquaculture has never been about food security. Farmed shrimp is a gourmet product, not a dietary staple. It is, as Elaine Corets remarked to me in Brazil, "an exotic species farmed in ponds created by destroying local ecosystems and exported to wealthy countries for the consumption of overweight people who don't need any more protein or cholesterol in their diet." In the places where shrimp is farmed, food security does not increase, it decreases.

Shrimp-farm expansion in the developing world has been driven by a burgeoning appetite for shrimp in the West. Shrimp consumption in the United States nearly tripled between 1980 and 2005, while the price halved. Those decades saw a seafood delicacy unknown to the majority of diners become a ubiquitous item on fast-food restaurant menus and in suburban kitchens. Cheap price, availability, perceived health benefits, and high culinary status all contributed to shrimp's popularity. In 2002, shrimp elbowed aside tuna as the number-one seafood in the United States, and has held that position ever since. Americans now eat roughly four pounds of shrimp per person per year.

What most American consumers don't realize is that almost 90 percent of shrimp is imported, and two-thirds is farmed product, mostly from Asia. Diners, sitting down to a platter of grilled, battered, or breaded shrimp, wouldn't be aware that what they're eating is most likely a farmed commodity rather than wild fare harvested by shrimpers in the South Atlantic or the Gulf of Mexico. They wouldn't know that U.S. shrimp-netting operations have been commercially kneecapped in recent years, unable to compete with the cheap influx of pond-raised product from abroad. And they certainly wouldn't know the backstory of shrimp aquaculture: the lost forests, the displaced lives. Advocacy groups are beginning to bring those stories to the fore, as they are with the entire industrial food chain, encouraging consumers to consider the provenance of their food as well as its quality and price. As Michael Pollan writes in his best-selling book The Omnivore's Dilemma, the questions we need to be asking are "What am I eating? And where in the world did it come from?"

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