Life cycle assessment of mussel and turbot aquacultureapplication and insights

Resumo

The path towards sustainability in the food sector demands the modification of the current operational and environmental patterns. In this sense, it is necessary to pursue reductions in the consumption levels for materials and energy, as well as the mitigation of the corresponding environmental impacts. Environmental management tools assist companies to monitor, manage and improve their environmental performance as well as to integrate environmental, economic and social issues. These tools enable the implementation of eco-efficiency strategies, life cycle thinking and environmental management systems into the business network. In particular, Life Cycle Assessment (LCA) is a well-known technique for assessing the potential impacts associated with a product. One of the sectors where LCA has been widely implemented is the agri-food sector. However, while LCA in agriculture is quite well established, the use of this tool to assess seafood production systems is a more recent phenomenon. This doctoral thesis contributes to widen the range of seafood species studied under an LCA approach. Furthermore, this dissertation develops new trends in LCA of seafood such as the combined application of LCA and Data Envelopment Analysis (DEA), or the implementation of Carbon Footprinting (CF) schemes. The Galician fishing sector is a key economic branch in Spain. Within this sector, there is an activity where Galicia arises as the national leader. This is the Galician aquaculture, which can be understood as a sector itself. This dissertation evaluates two reference species in the Galician extensive and intensive aquaculture: mussels (Mytilus galloprovincialis) and turbot (Scophthalmus maximus), respectively. The novel application of LCA to the mussel sector comprises a range of activities which can be grouped into four sub-sectors: mussel culture, dispatch centres, canning factories and cooking plants. Detailed inventories are presented for mussel farming, processing and consumption, as well as for the management systems regarding the valorization of mussel shells and mussel organic remains. From the environmental characterization of the Galician mussel sector, the main hot spots are identified and potential improvements are then proposed. The role of mussel purification centres is highlighted together with the influence of vessel operation and capital goods on the potential environmental impacts associated with mussel culture. The environmental performances of fresh, canned and frozen mussels are also compared. On the other hand, the application of LCA to the Galician turbot aquaculture is presented along with a previous LCA of feed for aquaculture. Thus, not only inventories for turbot farming and consumption are presented, but also inventories for the production of both marine and continental aquafeed. Therefore, recommendations for turbot producers and also for aquafeed manufacturers are gathered on the basis of the environmental characterization results. Furthermore, a rough comparison between intensive and extensive aquaculture practices is established by assuming turbot and mussels as their respective representatives. In this thesis, LCA is proved to be suitable for the assessment of the environmental performance of mussel and turbot aquaculture sectors. In this sense, LCA provides transparency and accountability all along the trade chain for mussels and turbot. Moreover, this dissertation gives insights on the potentials behind the use of CF and the combined application of LCA and DEA. DEA is a performance measurement methodology used to empirically quantify the comparative productive efficiency of multiple similar entities. The combined application of LCA and DEA joins the strengths and minimizes the weaknesses attributable to both methodologies so that a synergistic effect is achieved while maintaining a quantitative character. This thesis links both methodologies and proposes the development of two LCA+DEA methods depending on the objectives of the study. First, whether eco-efficiency verification is pursued, a five-step LCA+DEA method is recommended. By using this approach, the connection between operational efficiency and environmental impacts is revealed, quantifying the environmental consequences of operational inefficiencies. On the other hand, where the aim is to directly compute environmental impact efficiency and target environmental impacts, then a three-step LCA+DEA method is proposed. Finally, CF involves the estimation of the overall amount of GHG emissions associated with a product along its supply chain, even including use and end-of-life recovery and disposal. This dissertation discusses the potentials and drawbacks of CF while showing how to assess the carbon footprint of a certain canned mussel product according to the guidelines of an increasingly popular specification named PAS 2050. Emphasis is laid on the relevance of CF to promote the establishment of policies based on life cycle thinking, support decision making in organizations and provide product differentiation. Furthermore, the detailed calculation of the carbon footprint of a common triple pack of round cans of mussels supplies a reference point for those mussel processors who are interested in the implementation of a CF scheme in order to attain competitive advantages and anticipate future regulations on global warming.