Study suggests aquaculture is currently inefficient, wasting important nutrients while depleting global fish stocks

Atlantic salmon farming requires a high volume of wild fish as feed, but produces only a small percentage of the world’s farmed fish supply. A study published on March 1 in PLOS Sustainability and transformation by David F. Willer of the University of Cambridge, UK, and colleagues suggest that redirecting wild-caught fish to human consumption instead of salmon farming could reduce pressure on salmon stocks. fish while increasing seafood production.

The increased demand for seafood has led to an expansion of aquaculture. However, 90 percent of commercial fish food is made from food-grade fish such as sardines and anchovies that are edible for humans. To analyze the efficiency of aquaculture in terms of net nutrient production, researchers first quantified the amount of micronutrients and wild fish retained by fish-fed farmed salmon using 2014 data on the production of farmed salmon in Scotland. They calculated the volume of micronutrients used as inputs from aquaculture and compared it to the nutrient outputs from salmon aquaculture. Using this data, the researchers modeled several seafood production scenarios to assess the potential sustainability benefits of alternative seafood systems.

Researchers found that in 2014, 460,000 tonnes of wild fish were used to produce 179,000 tonnes of Scottish salmon. 76 percent of wild-caught fish were edible for human consumption. The data also suggests that several alternative models of seafood production would be more efficient in terms of net nutrient production, and therefore could significantly reduce the capture of wild fish while increasing the global supply of seafood. However , these data were limited to a single year (2014). Future studies are needed to better understand how to operationalize a global shift from farmed fish to sustainable fisheries.

According to the authors, “Food production now accounts for 90% of the environmental footprint of salmonid production. Allowing salmonid production to expand further via its current approach will place exceptional stress on already existing global fish stocks. Our results suggest that limiting the volume of wild-caught fish used to produce feed for farmed salmon can ease pressure on wild fish stocks while increasing the supply of nutritious wild fish. for human consumption.

The authors add: “Nutritious fish stocks are wasted by salmon farming. Scientists reveal that consuming wild fish intended for salmon farms would leave almost 4 million tons of fish in the sea while providing an additional 6 million tons of seafood.

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