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Farmed Salmon Develop Ear Deformities All Around the World
May31

Farmed Salmon Develop Ear Deformities All Around the World

By Roberta Attanasio Salmon farming is the fastest growing food production system in the world—accounting for 70 percent (2.4 million metric tons) of the market. Increasing demand is leading to the gradual development of responsible practices to minimize its negative impacts on the environment. Indeed, salmon farming is known to pollute the oceans, use toxic pesticides to control the spread of sea lice, foster diseases caused by viruses and bacteria, allow escapees, and deplete the stocks of forage fish—depending on the production region, 1.5 – 8 kilograms of wild fish are needed to produce one kilogram of farmed salmon. However, despite the development of the open and transparent production practices encouraged by the WWF in 2004, and currently managed by the Aquaculture Stewardship Council (ASC), salmon farming is plagued by numerous problems. A deadly algal bloom is killing millions of farmed fish salmon in Chile, causing a drop of 35% to 45% in exports this year. In addition, the recent research finding that farmed Atlantic salmon from Norway, Australia, Scotland, Canada and Chile are going deaf is both surprising and alarming, raising questions about animal welfare and conservation efforts. Farmed salmon have deformed otoliths (or fish earbones) and, as a result, poorer hearing. Otoliths are located behind a fish’s brain and are essential for hearing and balance, much like the inner ears of humans and other mammals. The typical structure of healthy otoliths is made up of calcium carbonate. However, in most farmed Atlantic salmon, the calcium carbonate is present in the otoliths in a different crystal form, leading to larger, lighter and more brittle structures. This deformity is very uncommon in wild fish. The researchers point out that the deformed earbones could be responsible for the low efficiency of conservation programs, thus explaining the origins of what, in the field, is considered a long-standing mystery. Every year, billions of captive-bred juvenile salmon are released into rivers worldwide to boost wild populations, but their survival is 10-20 times lower than that of wild salmon. The new finding may help explain this low survival rate. Hearing loss could prevent fish from detecting predators, and restrict their ability to navigate back to their home stream to breed. Researchers do not know what the triggering factor for earbone deformity is—they speculate it could be something in the fish’s diet, or a genetic component unique to the salmon selected to be farmed, or it could be related to their abnormally rapid growth rate. Salmon farming is a work in progress. Knowledge and experience, along with commitment to sustainable practices, are necessary for successful production. The unexpected finding of hearing loss in farmed salmon...

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Salmon Farming: The Chilean Massive Die-Off
May21

Salmon Farming: The Chilean Massive Die-Off

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...

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