The contribution analysis showed that the diet process contributed to the majority of the impacts. The sea bass rearing stage was the main contributor of eutrophication (more than 58% in TR and 52% in CR).The analysis revealed that the major of energy consumption was due to rearing phase through water pumping and oxygen injection and productio. with 175000 MJ/tonne and 280000 MJ/tonne. for TR and CR,respectively
For all the studied impacts,the assessment revealed that CR presented more environmental burden than TR. The major differences between the to farming system lay in Global Warming Potential GWP and energy use EU.
Feed efficiency seems to have a dominant influence on the level of impacts involving diet process.Undoubtedly,the shown difference in the environmental load is the direct result of the relative ability of fish reared in TR to better convert their diet into biomass with a feed conversion ratio of 1.7 compared to 2.1 in CR
There are many otions for improving the environmental performance of these aquaculture systems. The most important measure is to increase the feed efficiency through improvements in rearing mdoes, the diet composition and the optimisation of feeding practices.