By Roberta Attanasio
Salmon farming—the fastest growing food production system in the world—is going through hard times in Chile, the world’s second-largest salmon producer after Norway. Last year, Chile exported $4.5 billion of farmed salmon, but now a deadly algal bloom is killing millions of farmed fish.
A few months ago, an estimated 40,000 tons of salmon died in the Los Lagos region, which is known as the Switzerland of the Southern Hemisphere’s—the snow-capped peaks of the Andes Mountains tower over deep mountain lakes and green farming valleys, creating a fairy-tale landscape. Unlike Switzerland, the fairy-tale landscape extends down to the coast and its beaches, which became covered with dead sea creatures. “Heaps of dead whales, salmon and sardines blamed on the El Niño weather phenomenon have clogged Chile’s Pacific beaches.”
El Niño, which warms the equatorial Pacific, is certainly one of the factors to blame in the massive fish die-off. The warm water encourages the growth of toxic algae, which cause the so-called red tide—an algal bloom that turns the seawater red and makes seafood toxic. Although the red tide is a common, naturally recurring phenomenon in southern Chile, the extent of the current outbreak is unprecedented, so much so that it has been defined “one of the country’s worst recent environmental crises.” The toxic algal bloom threatens the local marine life as well as the livelihood of the fishermen who depend on it.
But, El Niño is only one of the factors responsible for the red tide. Liesbeth van der Meer, who heads the Oceana environmental group in Chile, believes that runoff from neighboring livestock creates concentrations of nitrogen that, when mixed with the above-normal temperatures, lead to the ideal scenario for the algae to grow. Another factor appears to be the salmon farming itself, which encourages toxic algal blooms. How? Nutrients dumped into floating salmon cages fall to the seabed forming underwater banks that act as a toxic algae reservoir. Marine biologist Hector Kol told The Guardian: “The problem we now have is a red tide of biblical proportions. Chiloé has changed, the sea is toxic. Right now we have a red tide with symptoms of diarrhoea, amnesia and paralysis from near the Straits of Magellan to Valdivia”—in other words, the phenomenon involves a stretch of more than 1,200 miles of coastline.
In addition, residents accuse salmon producers of exacerbating the algal bloom by dumping contaminated fish near the coast—millions of salmon died earlier this year due to another algal bloom that asphyxiated fish by decreasing oxygen in the water. Now, according to the Chilean government, scientists will determine whether or not dumping tons of rotting salmon into the Pacific contributed to the massive red tide. In the mean time, fishermen blockaded the principal access point to the island of Chiloé for two weeks, thus largely isolating its population and stranding some tourists. Felipe Manterola, general manager of SalmonChile, warned that if the blockade continued, the remaining healthy salmon could resort to “competition and cannibalism”. The Chilean setbacks have pushed up global farmed salmon prices. Chile’s exports will drop by 35% to 45% this year, resulting a monthly salmon shortage of between 15,000 metric tons and 20,000t a month to global markets.
Only a year ago, Chile salmon farmers used record levels of antibiotics to control the spread of an infectious microbe that was causing a lethal disease in their fish. As heavy use of antibiotics in animals can exacerbate the spread of drug-resistant superbugs, thus endangering human health, some U.S. grocery chains started to gradually eliminate farmed salmon from their shelves.