Assessment of nitrous oxide emission from mariculture of marine fish and crustaceans in China, 2003–2022

Aquaculture, as the fastest-growing food production sector in the world, is becoming an increasingly nonnegligible source of greenhouse gas emissions. Despite this, there has been limited research on nitrous oxide (N₂O) emission from marine aquaculture in China, where more marine aquaculture occurs than anywhere else, globally. We estimated N₂O emissions (E) from marine mariculture of 10 fish and 6 crustacean species in China from 2003 to 2022 using production data from China’s fishing industry statistical yearbooks (2004–2023), and data for feed conversion rates and types from the literature. From 2003, marine aquaculture production, the annual N₂O emissions (E_A), and the annual N₂O emissions per unit of aquaculture area (EI_A) trend upward. The E_A of fish culture was lower than that of crustaceans, but the EI_A of fish culture was generally higher. Sea bass (0.308 Tg·N·yr⁻¹) and white shrimp (0.945 Tg·N·yr⁻¹) had the highest average E_A among fish and crustacean cultures, respectively. The highest average E_A from fish and crustacean were both Guangdong Province (fish: 0.248 Tg, crustacean: 0.547 Tg), and the highest sea area were both the South China Sea (fish: 0.316 Tg, crustacean: 1.082 Tg); The highest average EI_A for fish and crustacean were Tianjin (35.40 t/ha) and Guangxi Province (19.83 t/ha), respectively, and the highest sea areas were both the South China Sea (fish: 0.316 Tg, crustacean: 1.082 Tg). These analyses provide baseline data for a greenhouse gas emissions inventory for China, based on an interpretation of them, we provide recommendations for reducing N₂O emissions in marine fish and crustacean culture.