The high FCR was the main reason that the
contribution from Pangasius farming to most impact
categories is greater than that from other fish culture
systems (see Table 7). The contribution to global warming
was comparable to that from Danish flatfish fisheries,
which was approximately 10 t CO2 per ton fish (Thrane
2006). The contribution of Pangasius farming to eutrophication
was similar to that of farming trout in flowthrough
but was greater than that for salmon and rainbow
trout. In all cases, the contribution to eutrophication was
mainly from the emissions of various nitrogenous substances
and, to a lesser extent, from phosphorous
substances. The contribution of transport was limited
(only 3% in the case of wheat bran). The emissions
related to rice bran were lower because the soil in the
paddies is almost permanently under water.