Chilean Coasts Devastated By Salmon Farming: Five Marine Reserves Have Salmon Farms Inside Of Them
In 2003, biologist Vreni Häussermann and a group of researchers started surveying underwater life at a site in the Comau Fjord, in Chilean Patagonia. The team found that sea cucumbers, bristle worms, anemones, corals, gorgonians, crustaceans and large schools of mussels abounded in the area. Every year for a decade, Häussermann, a German-Chilean scientist who has studied Patagonia’s marine ecosystems for more than 20 years, wrote down what she observed. Changes from one year to the next were very gradual, but when in 2013 she compared photographs she had taken with those from 2003, she realized there was almost nothing left of what she had seen the first time 10 years ago.
In 2003, dozens of Bolocera occidua anemones lived attached to the steep walls of the fjord’s reefs. Today, there are none left. Also, the density of gorgonians of the species Primnoella chilensis, which were abundant on the reef walls deeper than 20 meters (66 feet), has decreased. “We hardly saw them [rock crustaceans],” says Häussermann, a professor at San Sebastian University in the Chilean city of Puerto Montt. In just 10 years, the density of species decreased by 70%, according to a 2013 paper that summed up the decade of observations. “That is about a quarter of the density we had previously recorded,” Häussermann says.
The researchers concluded that the salmon industry had caused all these changes. The industry cultivates thousands of caged fish destined for export to the United States, Japan and Brazil, among other countries. Despite the scientifically proven impacts that salmon farming has on natural ecosystems, five marine protected areas in Chile have salmon-farming concessions within them.
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Despite the environmental importance of Patagonia, few protected areas here remain free from the salmon industry. The area made up of Katalalixar National Reserve, Laguna San Rafael National Park, and Bernardo O’Higgins National Park is the only spot between the two southernmost regions of Chilean Patagonia without any salmon farming, says Liesbeth van der Meer, director of Oceana Chile. It’s possible to see here what the ecosystems further north looked like before the arrival of the salmon farms: “very pristine, very prehistoric,” says van der Meer. “The anemones are very large.” According to Oceana, sea whips, snails, crabs, stars, sea spiders and dolphins all occur in the area. One can also watch sea lions feeding on large colonies of prawns that “on some occasions, spread like a large carpet all over the seabed,” according to an Oceana publication describing the findings from an expedition to Katalalixar.
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Studies have shown that one of the main impacts of salmon farming is oxygen depletion in the water, which then leads to the death of marine species in the area. This happens when salmon feces and excess fish food falls to the ocean floor and accumulates. The nutrients they contain trigger a microalgae bloom, which, according to Häussermann, grows and “lives for just a week or maybe a little longer.” When the algae die and sink to the seafloor, they’re consumed by bacteria that deplete the oxygen in the water, a phenomenon known as hypoxia. That leaves the seafloor “covered with white bacteria which generally means that there is no oxygen left,” Häussermann says. “The bottom is transformed into a kind of mud,” van Der Meer adds, and “anemones cannot live there, Chilean basket stars either. Everything that we have documented in Katalalixar cannot live there.”
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https://news.mongabay.com/2021/05/chiles-marine-protected-areas-arent-safe-from-its-salmon-farms/