Interactions between aquaculture and the environment remain a debated issue, especially in areas where the
aquaculture sector is still expanding, such as in theMekong delta in Vietnam. In response to environmental concerns,
various eco-certification schemes have been introduced for seafood, aiming to improve production practices.
In order to reflect upon the criteria of these certification schemes, life cycle assessment (LCA) was
applied to conventional and certified extensive organic mangrove–shrimp farms in the lower Mekong. In total,
21 organic and 20 non-organic farms were included in the study for evaluation of effects on global warming
(including emissions from land transformation and occupation), eutrophication and acidification. Monte Carlo
simulations and random sampling were applied to aggregate contributing processes into results. The emissions
of greenhouse gasses per ton of shrimp produced were substantial for both groups, and almost solely caused
by the release of carbon during mangrove land transformation. Differences in the land area needed to support
shrimp production explain the discrepancy. Organic farms emitted less CO2-equivalents (eq.) than the nonorganic
farms in 75% of the Monte Carlo iterations. Acidification impacts were similar for the two groups, with
higher emissions from the non-organic farms in 67% of the iterations. Meanwhile, most mangrove-integrated
farms showed a net uptake of eutrophying substances, indicating that both types of mangrove–shrimp production
systems are nutrient limited. In order to put the results into perspective, a comparison with intensive and
semi-intensive shrimp farmswas made.While the extensive mangrove–shrimp farms showed higher emissions
of CO2-eq. per ton shrimp produced (20 tons in average for organic and non-organic farms compared to 10 tons
from intensive/semi-intensive production), results indicated lower impacts in terms of both acidification and
eutrophication. We recommend LCA to be used as a central tool for identifying practices relevant for ecocertification
audits, including considerations for land use. However, a better understanding of the consequences
of land quality change and linkages to impacts at the ecosystemlevel e.g. effects on ecosystemservices, is needed