Assessing carbon greenhouse gas emissions from aquaculture in China based on aquaculture system types, species, environmental conditions and management practices

Aquaculture is one of the fastest growing food production sectors in the world, but many of the small-hold operations are poorly assessed for their climate impact. We analyzed the literature data on CO 2 and CH 4 fluxes from various aquaculture systems in China. The mean fluxes varied in the ranges of − 382.45–551.88 g CO 2 -C m −2 yr −1 and − 0.03–565.09 g CH 4 -C m −2 yr −1 . Aquaculture system reclaimed from mudflat had the highest CH 4 emission (54.92 ± 21.00 g C m −2 yr −1 ) but lowest CO 2 emission. Shrimp aquaculture and semi-intensive farming tended to yield higher CH 4 emission. Small and shallow systems had significantly higher CO 2 and CH 4 emissions, with chlorophyll a and dissolved oxygen concentrations as the main environmental drivers. Management practice such as drainage, exposure and desilting during the non-farming period significantly decreased CH 4 emission. We estimated that aquaculture systems in China emitted 181.66 Tg CO 2 -eq yr −1 , offsetting ~7% of the national terrestrial carbon sink, with most of the emission concentrated in coastal provinces and along the major rivers in the southeastern quadrant. This study highlights the importance of accounting for greenhouse gas emissions from aquaculture to improve the accuracy of the regional and national carbon budgets. • CO 2 and CH 4 emissions varied among aquaculture systems. • Aquaculture-emissions in China’s offset ~7% of terrestrial carbon burial. • Emissions were concentrated in coastal region and along major rivers. • Growth and intensification of aquaculture sector raises climate concerns.