The sustainability performance of the aquaculture sector, embracing environmental, economic, and social dimensions, is increasingly discussed concerning food production and resource management. To this purpose, the "DEXiAqua" evaluation model is a multicriteria decision analysis tool aiming at comprehensively assessing the environmental, economic, and social impacts of aquaculture systems. This model builds an attribute tree to delineate the complexities of sustainability, partitioning it into distinct branches for environmental, economic, and social aspects, further segmented into "sub-branches." Each branch is characterized by qualitative indicators, based on direct measurement or calculation. The model integrates established scientific methodologies such as Life Cycle Assessment, Life Cycle Costing, and Emergy accounting to calculate indicators, translated into qualitative scales using predefined thresholds. Weightings, termed utility functions, are then applied to aggregate sub-attributes into an overall sustainability score.
The aim of this study is to apply this methodology to an Italian land-based farm specialized in Gilthead sea bream and European sea bass in order to get an overall sustainability score.
The farm consists of several ponds and the production cycle starts with 3 g fry, for further growth till 400/600 g. Annual fish production reaches approximately 450 tonnes, with a Feed Conversion Ratio (FCR) of 2.4. Environmental, economic, and social data were collected by providing a questionnaire directly to the described company. Some of the main data collected include, for example, feed consumption, energy required, oxygen consumed, sales and purchase prices, gender equality, and employee workload.
The farm achieved a ’low’ environmental score (2/5), which highlights the environmental impact of traditional land-based aquaculture, particularly due to the high consumption of energy and oxygen. In addition, the use of commercial feed further reduces eco-efficiency due to the lack of reuse of co-products or locally sourced feed. The economic and social sectors score medium (3/5), favored on one hand by average efficiency and viability and working condition, but disadvantaged on the other hand, by a low score in ’local development’. Finally, integrating the three dimensions of sustainability, the overall sustainability score of the company is classified as ’medium-low’ (3/7).
Finally, the tool helps to define a strategy for the farm sustainability improvement.