An emerging environmental accounting approach to assess novel or underexploited ingredients: Emergy assessment of fishmeal from insects, poultry by-products, & microalgae

INTRODUCTION Fishmeal represents the optimal protein source to feed farmed fish and crustacean species. Increasing market demand and prices has been promoting the search for alternative protein sources in aquaculture. Other food supply chains currently present waste products that might be safely re-circulated in the economy. Four partial substitutes for fishmeal are here considered: two involving microalgae, one insect meal, and one the reuse of by-products from poultry farming. The results of the assessment applied to such alternative ingredients are presented and discussed in the light of their possible role in improving the integrated sustainability performances of the portion of the aquaculture sector related to protein fishmeal. Industrial innovation is mostly driven by economic reasons and consequent assessment from a receiver/consumer perspective. To counterbalance such knowledge in times of ecological crises and concerns, it is here proposed a comprehensive environmental assessment through an emerging approach, rooted in systems thinking and thermodynamics, able to offer a donor-side perspective, i.e. that of the geobiosphere. Such results are compared to the Life-Cycle Assessment of the same ingredients. MATERIALS AND METHODS The four partial substitutes for protein fishmeal are considered in operating plants located by the European coast of the Mediterranean sea, namely, in Northern Italy and Southern France. The following ingredients are here assessed: dried biomass from microalgal species Tetraselmis suecica and Tisochrysis lutea, instect meal from larvae of Hermetia illucens, and by-product meal from poultry farming. Such products and their related processes are elaborated through the Emergy Accounting (EMA) approach (Odum, 1996; Brown & Ulgiati, 2016). Results from the standardised Life-Cycle Assessment (LCA) (Arvanitoyannis, 2008; ISO, 2018) are also offered and discussed. Through EMA, the dependence on natural resources is further explored compared to the sole LCA. The two approaches can be seen as complementary, and are indeed increasingly used together when a comprehensive view on a process’ sustainability is required or desired. RESULTS The results show the insect meal has the highest environmental efficiency when expressed in emergy requirements per unit of product. The second highest efficiency is found in poultry by-product meal. This can also be found in LCA results. Microalgae seem to suffer from both low productivity and a significant use of seawater to be brought to the on-shore plants. However, some critical aspects emerge from five emergy indicators: the four processes all appear to rely on intensive industrial processes, with a poor use of local renewable sources and instead a high (99%) dependency upon resources from outer human economies (with no economy of scale being observed). For microalgae, the significant need for seawater, found through the EMA, is complemented by carbon dioxide and energy requirements, found via LCA. In the insect meal system, human labour (only measurable through EMA) plays a non-negligible role, while energy requirements are highlighted by both the approaches. Building upon such findings, possible approaches to make up for the current environmental issues are discussed. ACKNOWLEDGEMENTS The research leading to these results has received funding from the European Union’s HORIZON 2020 Framework Programme under Grant Agreement no. 773330. REFERENCES Arvanitoyannis, I. S. (2008). ISO 14040: life cycle assessment (LCA)–principles and guidelines. Waste management for the food industries, 97-132. Brown, M. T., & Ulgiati, S. (2016). Emergy assessment of global renewable sources. Ecological Modelling, 339, 148-156. Odum, H. T. (1996). Environmental accounting: emergy and environmental decision making. Wiley. Wackernagel, M., & Rees, W. (2004). What is an ecological footprint?. The sustainable urban development reader, 211-219.