The sea is calm at sunset on Quinchao, Tarsicio Antezana's home island in southern Chile. In the distance, the snow-capped volcanoes are tinged a deep violet with the setting sun.
It is a serene scene, except for one thing Antezana, a retired oceanographer, cannot ignore. Not far away, a swath of small rectangular objects stretches across the sea, rocking slightly with the tide. These structures might not look like much, but Antezana knows what lies beneath the surface: a salmon farm.
Underwater, high-density net cages house thousands of salmon. Farms like this one are common in Los Lagos, Chile's main aquaculture region. The South American country is the leading exporter of farmed salmon to the United States. However, the popular fish is not native to this location, and many environmentalists and activists have long complained that fish farms are damaging Chilean ecosystems and threatening native wildlife.
Large-scale salmon farming in Chile began in the 1970s. Antezana, then a young scientist, was commissioned to assess the feasibility of this activity. Antezana advised the government to conduct baseline studies and to beware of ecological and health risks.
For more than four decades, Antezana has seen the industry grow to become one of the world's leading producers of farmed salmon. Last year, farmed salmon was Chile's second largest export product, generating revenues of US$6.5 billion.
It is an economic success story in which U.S. consumers, who now consume more Chilean salmon than ever before, play a leading role; 2022 was a record year, according to the U.S. Department of Agriculture. Most of the farmed salmon purchased in the United States comes from abroad and, almost half, from Chile's fjords.
Its salmon farming industry has been widely criticized for intensive use of antimicrobials and accused of polluting waterways and contributing to record algae blooms. As primary aquaculture districts have deteriorated along with growing international demand, Chilean salmon farming has expanded into the pristine wilderness of the country's southernmost region, Magallanes in Patagonia.
In April, a report prepared for the United Nations called salmon farming "one of the major environmental threats facing Patagonia". David R. Boyd, an associate professor at the University of British Columbia, who prepared the UN report, recommended suspending "the expansion of salmon aquaculture pending an independent scientific analysis of adverse environmental impacts." This request was rejected by the industry.
Arturo Clément, president of SalmonChile, the industry association, acknowledged that the sector had "made mistakes in the past and that there is still a way to go". Over the last 40 years, salmon farming has become a vital industry for southern Chile, he explained. "We are convinced that care for the environment can be made compatible with economic development."
Antezana does not share this optimism. It is difficult to assess the extent of the damage caused to Chile's coastal ecosystems, he says, because baseline studies have never been carried out to monitor the effects of salmon farming on aquaculture.
Most Chilean salmon farms routinely treat fish with antibiotics and pesticides to prevent outbreaks of diseases such as piscirickettsiosis and infectious salmon anemia. According to Sernapesca, Chile's National Fisheries and Aquaculture Service, more than 338 metric tons of antibiotics were used in Chilean salmon farms in 2023. This is a significant decrease from several years ago, but well above industry targets to reduce use. In contrast, Norway, the world's largest producer of farmed salmon, reported virtually no use of antibiotics in the same year.
The rise of antibiotic resistance has been recognized by the World Health Organization as a serious threat to global public health. Aquaculture, including salmon farming, is contributing to this, according to Felipe Cabello, professor of microbiology and immunology at New York Medical College.
However, due to strict quarantine and testing protocols, Chilean salmon contains virtually no antibiotic residues when it reaches U.S. supermarkets. Both Chile and the United States test Chilean salmon flesh for antibiotics; however, Cabello noted that neither tests samples for bacteria, which could pose a public health risk.
If any bacteria had drug-resistant genes, he explained, they could pass into the intestinal tract of humans and transmit antibiotic resistance in a process known as horizontal gene transfer, in which genetic material can be passed from one bacterium to another. Cabello said researchers increasingly feared the development of antibiotic-resistant "superbugs," given that salmon farms may foster the ideal antimicrobial breeding ground, since 70 to 80 percent of antibiotics administered to salmon can pass into the environment.
Cabello noted that leaked antibiotics have been discovered in wild fish populations near Chilean salmon farms. When bad weather and poorly enclosed structures allow salmon to escape from fish farms in large numbers, predatory fish endanger local species, destabilizing ecosystems and transporting contaminants beyond their breeding grounds, he said.
Another cause for concern for some scientists is the feeding of farmed salmon, which is being replaced by protein crops such as soy and livestock by-products. Ivonne Lozano, a researcher and food safety expert at the University of Chile, said that the Chilean industry is feeding the fish food that to them is artificial.
Filtered food that falls to the seafloor, as well as fish feces and other nutrients, are believed to contribute to periodic harmful algal blo oms and oxygen-depleted zones called "dead zones" that kill ocean life. Lozano cited artificial feeding as one of three key factors contributing to disease in Chilean salmon farms, along with the high density of net cages and the fact that salmon are not native to the region.
Since 2014, the Monterey Bay Aquarium's Seafood Watch program, a global authority on sustainable seafood, has advised consumers to avoid almost all salmon farmed in Chile, alluding to the industry's reliance on antibiotics.
For the past five years, the non-profit organization has been working with Chilean industry groups to cut antibiotic use in half by next year. Chilean salmon trade groups say that, looking over a longer period of time, the volume of antimicrobials is trending downward. While their use decreased some years, in 2021 it increased significantly, by 34 percent. The most recent data show that the amount of antibiotics used in 2022 was higher than when the partnership began.
Liesbeth van der Meer, vice president of Oceana Chile, a nonprofit conservation group, said it seemed almost impossible to reach that goal.
Another initiative, the Yelcho Project, is presented as the first public-private effort to reduce the use of antibiotics, and brings together government agencies with Chile's largest salmon companies and industry groups such as SalmonChile.
In the face of pressure on the industry to reduce antibiotic use, southern Patagonia is very attractive. Clément argued that the region's cooler waters would limit disease outbreaks, which in turn would facilitate a decrease in antibiotic use.
In search of cleaner farming sites, the industry has moved into the Magallanes region. According to some researchers and activists, this could have catastrophic consequences for local ecosystems and human health, and many question whether economic growth justifies industrial aquaculture.
Antezana's palafito faces waters that have long been used for aquaculture. He has seen firsthand the piles of garbage and waste that salmon farming companies abandon in Los Lagos when they leave. The garbage remains on the shore for months and, in some cases, only the indignation of the neighbors forces the companies to clean up. Antezana assures that these same problems will go south with the fish farms.
In the Magallanes region there are around 130 salmon farming concessions, or licenses for fish farms. That is fewer than in other major aquaculture regions of Chile, although typically only 50 of them have fish each month, according to a Sernapesca spokesman. However, salmon farming has expanded in the province, which has the highest number of licenses pending, according to Chile's salmon regulators.
The Magallanes region is home to a third of the world's marine biodiversity and several protected species, such as the blue whale, the Magellanic penguin and the Chilean dolphin.
Experts from the Interdisciplinary Center for Aquaculture Research at the University of Concepción say that the introduction of salmon may affect invertebrate organisms unique to the region, such as cold water corals and sponges. And since farmed fish feed on soybeans, the chemical composition of the sea will most likely change, as has happened in the waters of Los Lagos in northern Patagonia.
Production in Magallanes will increase at first, said Cabello, who assured that if they continue doing the same thing, productivity will drop again after a few years and they will have the same problems: infections and excessive use of antimicrobials.
However, Clément stated that the conditions in Magallanes were different from those further north, so the result would not be the same.
Antezana expressed concern that the bacteria had a lower metabolism, which would slow down the decomposition of agricultural byproducts. He stated that the industry had gone south because the waters were not polluted and because they could say they were getting clear water from glaciers, which sounds very convenient.
In addition, because the cold water is denser, it is more likely to be trapped in the deep micro-basins of the Magallanes region, which could lead to an accumulation of organic matter, he explained.
Industrial groups are pushing to increase production. Clément stated that the licenses they have in this region of Magallanes are very limited, so a discussion is required.
The extent to which the salmon industry will be able to expand in southern Patagonia is uncertain. Antezana pointed out that the relocation is being carried out without scientific evidence or rigorous studies to establish the possible limits of production.
Politicians have debated whether to stop or limit new fish farm concessions in the southernmost waters.
In March 2022, Gabriel Boric was sworn in as the youngest president in Chile's history. Boric, now 38 years old, has tattoos in honor of the region where he grew up: Magallanes.
Even before he was elected, the leftist political leader was a harsh critic of the salmon industry, giving environmentalists hope for a new advocate to fight the industry's territorial expansion.
When he came to power, he promised to reform Chile's constitution, in place since the Pinochet era. Voters rejected a 2022 referendum that would have brought sweeping environmental reforms. Last year, a second referendum also failed.
A new law requires salmon farming companies to make public the amount of antimicrobials they use, as well as their biomass and mortality rates.
Groups such as Oceana and indigenous activists continue to call on Boric to do more.
Leticia Caro, from the Kawésqar indigenous community, said she had already witnessed the devastating effects of the salmon industry on her people's ancestral territory in the Magallanes region. She described the contamination of the seabed, the loss of native fish species on which her community depends for food, and the dumping of industrial waste in her community's fishing grounds.
The Kawésqar have navigated these waters for thousands of years. "In the sea we live and coexist with spirits and energies," Caro said through an interpreter. "We want them to leave the territory," he added.
But some Kawésqar are in favor of the economic advantages of aquaculture.
Caro wants protected areas to be respected, no new hatcheries to be allowed and sanctions to be imposed on companies that cause damage.
Many indigenous peoples in Chilean Patagonia have waged legal and political battles to regain their land and water rights. These disputed areas are considered vital by the salmon industry. In June, indigenous groups in two regions (Aysén and Los Lagos) failed in their attempts to recover their land and water.
Clément, of SalmonChile, understands the consumer appeal of fish farmed in remote southern Patagonia, which are highly nutritious, healthy and sustainable and come from very pure waters.
It is unclear how long southern Patagonia will remain so pure. Insisting that Americans should stop buying Chilean farmed salmon, Caro said that "there is still time to preserve the only place in the world that remains pristine."
Antezana also believes that outside pressure will make a difference.
Halfway through the presidential term, both believe that the government alone will not be able to protect southern Patagonia from salmon farming expansion.
Antezana assured that although he does not have much hope, he will continue to fight.
John Bartlett contributed to this story. The first stories were funded by the Internews Earth Journalism Network, a non-profit organization.
