Primary data from laboratory experiments were collected to fill mass balances in the case of LS scenario. Dedicated checklists were adopted. Background data were compiled through the use of on the Ecoinvent database. On the other hand, SU model has been elaborated referring to the methodologies described by Maranghi and co-workers 15 and Piccinno. In both cases, the partial lack of useful data has been offset by the elaboration of assumptions, validated and justified by considerations based on previous studies found on the literature or relying on the Ecoinvent database. The unitary processes are listed in ESI (Table ). A detailed description of the main approximations and of the product system is reported below. Materials and energy flows involved in each step of the system are listed in Table . i) The AnR used as primary source for the AnO is considered waste with negative market value. For this reason we conservatively applied the criterion "zero burden" and no environmental impacts have been attributed to its production, even though it is known that rapid microbial degradation of fishery waste actually contributes to pollute landfills, land or sea. It has been instead considered the AnR supply contribution due to transportation, by including 30 km distance covered by truck.