Summary:
New research shows that excessive use of protein-heavy fish feed can turn aquaculture ponds into hotspots for methane (CH₄) emissions, with rates up to 155 times higher near feeding zones. The study found that anaerobic protein degradation produces nitrogen- and sulfur-rich compounds that fuel methane release, mimicking the conditions of biogas reactors.
Globally, aquaculture ponds cover more than 8 million hectares and are increasingly recognized as major CH₄ sources. In the German study site, bubble-driven methane release from sediments near feeding areas accounted for nearly all pond emissions, reaching record levels. Detailed chemical analysis confirmed that protein-derived compounds strongly correlated with methane production.
The findings underscore how inefficient feed use – with most nitrogen from protein lost to sediments rather than converted into fish biomass – drives greenhouse gas emissions. Researchers conclude that better feed strategies, including reduced protein content and alternative systems like biofloc, are essential for lowering aquaculture’s climate footprint.