Environmental impact of different Mediterranean technological systems for European sea bass (Dicentrarchus labrax) and Gilthead sea bream (Sparus aurata) farming

As at a global level, the aquaculture sector is growing in Italy too and, among the various species, European sea bass and Gilthead sea bream are becoming increasingly important. As a consequence, the environmental implications are an emerging issue and in-depth studies on the topic of farm sustainability are needed. This study compared the environmental performance of four specialised Sea bass and Sea bream farms in Italy, characterized by different technological system, using the Life Cycle Assessment approach. 1 tonne of fish biomass harvested and 1 kg of fish protein were chosen as functional units. The 'from cradle to gate' perspective was applied to define the system boundaries. The results revealed that land-based farms had higher environmental impacts compared to coastal farm with a Climate change of 9660 and 7250 kg CO2 eq for the former and 2443 and 3308 for the latter. Despite the use of aquafeeds emerged as a significant contributor of environmental impacts across all farms (with a share of more than 80 % of the Climate change in the coastal farms), even energy and liquid oxygen consumption, particularly on land-based farms, played a crucial role (with impact shares of 25–40 % in climate change). A sensitivity analysis on energy sources revealed that the use of more renewable energy can reduce the Climate Change of land-based farms by an average of 5 %, while an all-biodiesel fleet has a beneficial effect on particulate matter (-7.5 %) and acidification (-6 %) on coastal farms. The study provided a comprehensive overview of the environmental impact of Italian ESB and GSB production. In addition, highlighted areas for further research, including biofouling mitigation, optimization of energy consumption, and exploration of alternative oxygenation methods in land-based farms. •Land-based marine aquaculture has higher environmental impacts than coastal farms.•Feed represents the main environmental hotspot of both farming systems.•Electricity and liquid oxygen determine significant impacts in land-based farms.•Renewable energy sources can decrease some impact categories in both farming systems.