About

One of the significant sustainability challenges of the 21st century is reducing the environmental footprint of food production while alleviating widespread inequities in access to nutritionally complete diets. Animals, both wild and farmed, are key components of the global food system, and per capita consumption of meat and fish is increasing worldwide. Historically, the consumption of domesticated mammals and birds was complemented by harvesting a wide array of fish species from oceans, lakes, and rivers. In the last 20 years, the exponential expansion of fish farming has made it the fastest-growing sector of the global food system. Aquaculture is widely seen as key to eliminating malnutrition while minimizing the environmental externalities that plague other animal source foods (e.g., greenhouse gas emissions, land-use change, overexploitation, yet its sustainability is intensely debated. Further, the nutritional value of farmed fish relative to other animal source foods remains uncertain.

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Animal production systems vary widely in the environmental externalities they produce, depending on land use requirements and inputs such as energy and feed, which result in greenhouse gas (GHG) emissions. Aquaculture production has often been positioned as a sustainable option. For example, producing one ton of beef requires about 32 times more land area than producing one ton of farmed fish. However, the ecological cost of fish production is not homogeneous. In this context, the environmental footprint of aquaculture could vary depending on whether primary forest was cleared or whether aquaculture ponds were built on already degraded pasture. Additionally, GHG emissions per mass of farmed fish produced can also vary by orders of magnitude, depending on the fish species cultured. While the environmental externalities of terrestrial animals (e.g., beef, poultry, pork) have been well studied in several regions of the world, GHG emissions and land use associated with aquaculture production are poorly understood.

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Animal foods also vary in their nutritional quality and accessibility. In comparison to poultry and cattle, fish tend to have a higher content of essential nutrients such as omega-3 fatty acids. Yet different types of fish vary widely in their nutritional value. Generally, small fish are more nutrient-rich than large species that are often preferred for cultivation. Given these nutritional differences, dietary substitutions of wild with farmed fish may exacerbate already high malnutrition rates. Additionally, wild fish tend to be less expensive than farmed meat and fish, which can exacerbate inequities in access to animal source foods. Finally, aquaculture production is generally concentrated near urban centers, in contrast to wild capture fisheries that require traveling long distances to reach the remaining productive areas. All of these challenges have emerged in the last 30 years, potentially driving transformative alterations in rural-urban ecosystem service linkages.

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This project will focus on the emergence of aquaculture in the Amazon, Earth's largest and most diverse river basin. As in other regions, cattle, pigs, and chickens have long been supplemented by capture fisheries in the Amazon, but aquaculture is growing rapidly. Favored by government and multilateral support, Amazon aquaculture is increasingly viewed as a pathway toward a sustainable bioeconomy by increasing the availability of fish, creating new commercial ventures, and providing an alternative to destructive cattle ranching. Yet, the nutritional and environmental consequences of the current pivot toward aquaculture are poorly understood, and its benefits may be exaggerated. We will evaluate the pace and implications of rapid aquaculture growth in two regions of the Amazon, thereby laying the groundwork for devising general rules-of-thumb for sustainable aquaculture.

This project will support food system sustainability by addressing three questions:

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(1) What is the trajectory of aquaculture expansion in the Amazon?

(2) How does the environmental impact intensity of Amazon aquaculture compare to alternative animal source foods?

(3) Which portfolios of animal source foods are best able to meet human nutritional needs with the lowest environmental cost?

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Our analyses will elucidate the potential for aquaculture in the Amazon to play a constructive rather than an environmentally destructive role in meeting the increasing demand for animal source foods.