Multi-scale integrated evaluation of the sustainability of large-scale use of alternative feeds in salmon aquaculture

The steady increase in production volume of salmon aquaculture has sharpened concerns about its sustainability. In particular the production of salmon feed is a reason for concern given its reliance on scarce natural resources, such as wild fish captures. Multi-scale integrated analysis is put forward as a tool to anticipate the environmental and socio-economic impacts of large-scale implementation of alternative salmon feeds, considering both plant and insect sources as potential replacements of fish meal and fish oil. The proposed accounting framework, based on relational analysis across hierarchical levels, describes the patterns of required inputs using biophysical and economic variables. It also considers the inputs used by external systems for the production of imported feed, thus providing a coherent assessment of the sustainability of the production system in terms of feasibility, viability, and desirability. The analytical tool-kit is illustrated in conceptual terms and then applied to the Norwegian salmon aquaculture, both in diagnostic (describing the actual situation) and anticipatory mode (examining feed scenarios). Results are used in an exercise of quantitative story-telling to check the quality of the narratives currently shaping policy discussions on aquaculture. Quantitative story-telling is a heuristic approach aimed at checking the robustness of knowledge claims in face of uncertainty. It is concluded that rearing insects in the salmon feed production chain enlarges the option space of feed sources by opening up the possibility of using locally-produced seaweed and organic waste, but also raises the level of uncertainty with regard to the possible insurgence of negative side effects.publishedVersio

Multi-scale integrated evaluation of the sustainability of large-scale use of alternative feeds in salmon aquaculture

The steady increase in production volume of salmon aquaculture has sharpened concerns about its sustainability. In particular the production of salmon feed is a reason for concern given its reliance on scarce natural resources, such as wild fish captures. Multi-scale integrated analysis is put forward as a tool to anticipate the environmental and socio-economic impacts of large-scale implementation of alternative salmon feeds, considering both plant and insect sources as potential replacements of fish meal and fish oil. The proposed accounting framework, based on relational analysis across hierarchical levels, describes the patterns of required inputs using biophysical and economic variables. It also considers the inputs used by external systems for the production of imported feed, thus providing a coherent assessment of the sustainability of the production system in terms of feasibility, viability, and desirability. The analytical tool-kit is illustrated in conceptual terms and then applied to the Norwegian salmon aquaculture, both in diagnostic (describing the actual situation) and anticipatory mode (examining feed scenarios). Results are used in an exercise of quantitative story-telling to check the quality of the narratives currently shaping policy discussions on aquaculture. Quantitative story-telling is a heuristic approach aimed at checking the robustness of knowledge claims in face of uncertainty. It is concluded that rearing insects in the salmon feed production chain enlarges the option space of feed sources by opening up the possibility of using locally-produced seaweed and organic waste, but also raises the level of uncertainty with regard to the possible insurgence of negative side effects

A holistic framework for the integrated assessment of urban waste management systems

We report on the development of a holistic framework to organize and integrate quantitative information characterizing the performance of Urban Waste Management Systems (UWMS) across dimensions and scales. The framework builds on the theory of metabolic networks and the Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM) accounting method. We perceive the UWMS as an organ of a socio-ecological system that modulates the interaction between the metabolic processes of the urban area and those of the embedding ecosystems providing inputs and local sink capacity. Building on these premises, we can define: (i) the flow of wastes produced by the urban system in quantity and quality; (ii) the mix of inputs required for the operation of the different stages of the waste management process, such as technology, labor, energy, water and material flows; (iii) the degree of openness of the system, that is, the imports and exports of urban waste flows in the different stages of its operation; (iv) the final outputs released into the local environment. The proposed framework can accommodate various indicators referring to the socio-economic performance of the UWMS (viability and desirability) and those related to environmental impact/stress (feasibility). Theoretical considerations are illustrated with preliminary data from a case study on the Metropolitan Area of Naples, Italy

Development of a municipal solid waste management decision support tool for Naples, Italy

Naples has experienced serious waste mismanagement during the last several decades. Illegal waste trafficking, the lack of an appropriate municipal solid waste management plan, and the subsidizing of energy generation from indiscriminate waste incineration generated social unrest and an unremitting paralysis of waste services throughout much of the late 1990s and early 2000s. The waste situation in Naples is a “hot spot” that cannot be simply described or explained by theoretical and linear models or analyses based on conventional waste indicators. A novel approach for the assessment of urban solid waste management system performance is proposed to overcome the limitations of conventional methods. When dealing with the production and use of scientific information for governance, scientists, especially those used to just “crunch numbers” have a serious problems in providing a useful input to the process of decision making. This paper presents a method useful for organizing a process of production and use of scientific information in which both scientists and the other social actors can have a bidirectional and constructive exchange of information. The goal of this method is to guarantee the quality of the process of generation and use of quantitative science to generate informed deliberations about policies over Municipal Solid Waste Management. The proposed approach builds on metabolic network theory and multi-scale integrated analysis of societal and ecosystem metabolism (MuSIASEM). The current metabolic pattern of municipal solid waste in the Metropolitan Area of Naples is described and quantified across hierarchical scales and dimensions. The analysis shows that the current Neapolitan waste management system is characterized by an elevated share (60%) of waste treated outside of the metropolitan ambit, and a low rate of separate collection (37%). Simulation of (i) metropolitan self-sufficiency of urban waste final disposal, and (ii) increased recycling rate show, respectively (i) an increase in both financial burden and local environmental impact; (ii) a lessening of the local environmental impact and an increase of running costs and higher need of local waste processing capacity