Freshwater aquaculture is an increasingly important source of blue foods but produces substantial methane and nitrous oxide emissions. Marine aquaculture, also known as mariculture, is a smaller sector with a large growth potential, but its climate impacts are challenging to accurately quantify. Here we assess the greenhouse gas emissions from mariculture’s aquatic environment in global potentially suitable areas at 10 km resolution on the basis of marine biogeochemical cycles, greenhouse gas measurements from research cruises and satellite-observed net primary productivity. Mariculture’s aquatic emissions intensities are estimated to be 1–6 g CH₄ kg⁻¹ carcass weight and 0.05–0.2 g N₂O kg⁻¹ carcass weight, >98% and >80% lower than freshwater systems. Using a life-cycle assessment approach, we show that mariculture’s carbon footprints are ~40% lower than those of freshwater aquaculture based on feed, energy use and the aquatic environment emissions. Adoption of mariculture alongside freshwater aquaculture production could offer considerable climate benefits to meet future dietary protein and nutritional needs.

淡水水产养殖是蓝色食品日益重要的来源，但会产生大量的甲烷和一氧化二氮排放。海水养殖，也称为海水养殖，是一个规模较小的部门，但具有巨大的增长潜力，但其对气候的影响难以准确量化。在这里，我们根据海洋生物地球化学循环、研究巡航的温室气体测量和卫星观测的净初级生产力，以 10 公里分辨率评估全球潜在适宜区域海水养殖水生环境的温室气体排放。海水养殖的水生排放强度估计为1-6 g CH ₄ kg ^-1胴体重量和0.05-0.2 g N ₂ O kg ^-1胴体重量，比淡水系统低>98%和>80%。通过使用生命周期评估方法，我们发现基于饲料、能源使用和水生环境排放，海水养殖的碳足迹比淡水养殖的碳足迹低 40% 左右。采用海水养殖和淡水水产养殖生产可以带来相当大的气候效益，以满足未来的膳食蛋白质和营养需求。