Food Safety News writer Ross Anderson recently toured Chilean fish farms and processing plants as a guest of Salmon of the Americas, a Chilean trade organization. This is the first of two reports.

Puerto Montt, Chile — Five years ago, while much of the world teetered toward an epic economic collapse, this bustling fishing port in southern Chile plunged into a crisis of its own. But, instead of a castrophic failure of banking and real estate, Chileans found themselves dealing with an invisible virus that had travelled literally from the opposite end of the earth.

In just two short decades, enterprising Chileans had built a thriving, $3 billion-a-year aquaculture industry, growing salmon in floating pens, processing them in and around Puerto Montt, then shipping their prized fillets off to the US, Japan, Europe and beyond. But in 2007, those pens were infested with a lethal microbe that wiped out millions of fish and threatened to kill the industry.

Now those salmon farms are back; Chile expects a new production record this year – a staggering 700,000 metric tons of Atlantic and Pacific salmon. Along the way, enterprising fish farmers learned some essential lessons about the risks surrounding microbiology and the recurring “tragedy of the commons.”

For most of the 20th century, Puerto Montt was a small, ramshackle seaport perched on a verdant ledge between an inland Patagonian fjord and the dramatic volcanoes of the southern Andes. It’s a lush, rain-soaked region resembling the northwest coast, sparsely populated with the descendants of the native Mapuche natives and German immigrants who arrived in the first half of the 19th century.

Then, in the mid ’80s, Chile learned that their plankton-rich, inland waters were ideal habitat for salmon aquaculture – even though there were no native salmon runs in Patagonia or anywhere else in the southern hemisphere. Using eggs and technology imported from the U.S. and Norway, they hatched and grew juvenile fish in local freshwater lakes, then transferred them to floating netpens, many of them along the shores of rural Chilhoe Island, south of the port city.

Fueled initially by Japanese investment, dozens of huge fish farms sprouted along Patagonian shores. The industry grew at a phenomenal rate averaging 25 percent per year. In 1990, Chilean farms exported nearly $100 million worth of salmon to Japan, the US and Europe. By 2000, it was $1 billion. Six years later, it was $2 billion.

U.S. buyers included Walmart and Costco, both of which sold Chilean salmon by the truckload.

Puerto Montt became a boomtown, employing some 35,000 people at the farms, processing plants, and fish food factories that converted fish waste and other raw materials into pellets. Construction boomed as well, with processing plants, thousands of homes for newly arrived workers, and a modern office building with a two-story underground shopping mall.

“The growth was much faster than the government could keep up with,” says Carlos Odebret of Salmon Chile, a trade group for the industry. “The challenge was to bring people in from other parts of the country.”

As the profits mounted, the companies kept building more and more fish farms – steel grids, comprised of 10 or more pens per complex, adding up to floating farms that cover an area the size of three football fields.

But aquaculture experts and environmentalists worried that they were growing too fast, taking too many shortcuts with the complex science of fish farming. There were too many farms, packed with too many fish, and not enough biological precautions.

“Salmon farming is starting to transform the ecology and environment of southern Chile, with tens of millions of salmon living in vast ocean corrals,” wrote environmental writer Charles Fishman. “Who could have predicted that the mass forced farming of an exotic fish to please the Wal-Mart low-price palate would result in a horrific virus-borne plague?”

Adolfo Alvial, a softspoken marine biologist widely respected in the industry, worried that it was all happening too fast. In July, 2007, he took a job with Marine Harvest, one of the world’s biggest aquaculture companies. At his first meeting, he was told the company “has an ISA situation” at one of its farms.

Infectious salmon anemia, better known as “ISA” is a virus closely related to influenza. It does not affect humans, but it is lethal to salmon, and especially to the Atlantic salmon which dominated Chile’s fish farms. It had previously infected salmon farms in Norway and Scotland, but this was Chile’s first experience with the disease.

The ISA quickly became an epidemic. Millions of fish died, and millions more had to be destroyed in an attempt to prevent its spread.

The infected eggs probably came from Norway, but the epidemic was worsened by the fish-farmers’ rapid growth and lax standards.

More than 13,000 people lost their jobs, forcing many to pack up their families and migrate north in search of work. “So it was also a social crisis for the region,” says Odebret. “We didn’t understand how important our industry was to the community. Now we do.”

The low point came in 2010, when Atlantic salmon production dropped to half of its 2008 peak.

But the fish farmers have recovered remarkably fast, due to a combination of strategies. Among them:

– They shifted much of their production to Pacific salmon, Northwest coho and closely related steelhead trout, which are more resistant to ISA. The record 2012 exports will be comprised of half Atlantics and half Pacific species.

– The density of the farms has been cut by half, and the number of farms in the Puerto Montt region has been frozen; future development will occur in areas to the south where there has been limited aquaculture.

– The aquaculture companies have adopted strict, new “bio-security” measures at the farms and processing plants. Individual farms are isolated from each other, with no movement of fish between them. At each stage in the process, workers wear disposable gowns and rubber boots with cleaning stations and foot disinfectant pools at critical points. The processing plants now resemble surgical wards, with workers draped completely in clean, disposable gear.

– With the support of the industry, the government has instituted strict new rules for fish farms, with more frequent inspections and biological monitoring.

– New hatcheries are coming on line using self-contained water supplies that are less subject to contamination.

Adolfo Alvial, who watched it all happen, believes the industry now understands the so-called “tragedy of the commons” – the economic principle that people who make their livings by exploiting a common resource do not have an incentive to take care of it. In the case of commercial fishing, that means fishermen will knowingly catch the last salmon because, if they don’t, somebody else will. In the case of aquaculture, it means fish farmers will keep producing more and more fish until the ecosystem collapses.

“We blamed the ISA virus on eggs imported from Norway,” Alvial says. “But the real problem was overcrowded conditions in our pens. We weren’t paying attention to the long term effects of these mega-farms.”

Scientists now understand that the oceans are made up of interrelated ecosystems. And any ecosystem has a carrying capacity, an ill-defined capacity for how much life can be sustained by the available food and oxygen.

“It’s human nature,” Alvial says. “We were so arrogant. This little country in South America showing the world how to build a world class aquaculture system. And we weren’t listening to the people who were telling us: You’re taking too many risks, not enough research, not enough regulation.

“So it may have started with a single lot of eggs from Norway, or a single boat or a single net… But we can’t blame our crisis on a few contaminated eggs. We have to blame it on our lack of knowledge of the carrying capacity.”

Fortunately, he says, the same entrepreneurial spirit that built the industry was marshaled to respond to the crisis. “We are a very opportunistic country.”

(Tomorrow: Farmed salmon vs. wild salmon – a religious question?)

Images courtesy WarnerHansen

Cover image: Millions of salmon are hatched in freshwater hatcheries and raised for the first few months before being transferred to floating saltwater pens.

Top to bottom images: 

1. The surface of a floating netpen boils with hungry salmon when automatic feeders spring into action, flinging food pellets out like a lawn sprinkler.

2. Individual salmon portions are prepared for freezing and vacuum packaging, bound for US markets.

3. Workers draped in sanitary outfits prepare salmon in a Puerto Mont-area processing plant.

4. Individual salmon portions are brined in preparation for smoking at a Chilean plant.