Salmon aquaculture threatens Patagonia.

In March, a massive die-off of farmed salmon sent more than 2.2 million kilos of rotting fish biomass into the fjords and channels of the Pacific Patagonian wilderness (1), critical areas for biodiversity conservation. The mass mortality event is part of a pattern in which industrial salmon farming increases eutrophication and boosts harmful micro-algae blooms (2), which enter gills and suffocate fish (3). In turn, decomposition of salmon carcasses leads to increased dissolved organic matter, which, in combination with human-induced ocean warming, facilitates the occurrence of more algal blooms (4). With a new constitutional act under discussion, Chile should seize this opportunity to add regulations that will stop the cycle and protect the valuable Patagonian region.