Bivalve farming is an economically and ecologically valuable way to satisfy the growing food demand in the world. As a typical category, oyster made up over 40% of the farmed bivalve, with a significant growing potential. Quantifying life cycle greenhouse gas (GHG) emissions of oyster farming is fundamental to determine the benchmark of emission reductions, which has been overlooked. This study evaluated the “cradle to gate” GHG emissions of the Pacific oyster (Crassostrea gigas) farming in China. The “cradle to gate” life cycle of Pacific oyster farming includes the unicellular algae culture, hatchery culture, and the farming process in the sea. The results showed that, the farmed oyster have significantly low life cycle GHG emission (92.97 kg carbon dioxide equivalents per ton of fresh oyster). For per kg of protein harvesting, the GHG emissions of oyster are only about 3.30% of those of beef. Farming in the sea contributed the most of the total GHG emissions, which is 38.75%. Hatchery culture contributed 37.99% of the total GHG emissions, while algae culture in seedling stage only accounted for 1.43%. In 2021, oyster farming could provide 0.15 Mt high quality protein for food in China. This amount of protein could reduce GHG mission of 15.33 Mt CO₂-eq when compared to beef production. The GHG emissions of oyster farming can be further reduced through integrating renewable energy technology, improving farming technology and the survival rate of young larva, utilizing environment-friendly materials in the framing process of Pacific oyster. These actions could help reduce life cycle GHG emissions by about 10-30%.
 

Pacific oyster; Carbon; Life cycle assessment; Greenhouse gases; Hatchery culture