Global aquaculture review reveals feed production and methane as primary drivers of industry greenhouse gas emissions

Global review by Professor Hong Yang analyzes how feed and methane drive aquaculture emissions, identifying sustainable paths for the fish farming industry.

By: AXL Media

Published: Apr 30, 2026, 8:57 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Complex Climate Footprint of Global Aquaculture

As the global population rises and dietary habits shift, aquaculture has become a dominant force in food production, yet its environmental cost remains a subject of intense scientific scrutiny. A comprehensive review led by Professor Hong Yang from the University of Reading has analyzed over 1,800 publications to determine the net greenhouse gas impact of the industry. According to the study published in Frontiers of Agricultural Science and Engineering, the industry is neither a uniform carbon source nor a sink, instead, its climate impact is determined by four specific operational stages. These include the production of feed, energy use during farming, biogeochemical processes within the water, and the initial land-use changes required for infrastructure construction.

Feed Production and the Dominance of Methane

The research highlights a critical divide between different farming methods, noting that feed production is the single largest emission source for most fed systems. In Chinese aquaculture studies, this stage alone accounts for 52% of the carbon footprint. However, in regions where freshwater pond farming is the standard, methane emissions take a much more significant role. The study indicates that methane contributes approximately 90% of total greenhouse gas emissions in these specific systems. This disparity suggests that the environmental weight of a seafood product is heavily influenced by whether the species requires supplemental feeding or relies on natural pond ecosystems.

Species Variation From Carbon Sinks to Livestock Equivalents

There is a stark contrast in emission intensity depending on the species being cultivated. According to Professor Yang’s research, unfed organisms such as seaweed, clams, and oysters have extremely low emissions and can even act as carbon sinks through the process of carbon sequestration. Conversely, intensively farmed carnivorous species, including salmon, trout, and shrimp, require high energy and feed inputs that result in significant carbon footprints. The study notes that the emission intensity of these high-demand species is sometimes comparable to that of terrestrial livestock, challenging the perception of all seafood as a low-carbon protein alternative.