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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Waste in the Food Supply Chain: A Case Study of the UK Salmon Industry

The global population is expected to reach 9.7 billion by 2050, putting added pressure on food systems. In 2018 a United Nations Food and Agriculture Organisation report recorded that globally a third of all fish is wasted before reaching the consumer. The focus must be on reducing food waste and not just increasing production to meet demand. It is the aim of Sustainable Development Goal 12.3 to halve per-capita global food waste by 2030 by working to reduce food losses along the production and supply chains. Demand for salmon fish products is growing and Scotland is looking to double its production by 2030 to keep its share of the global market. To enable and better inform sustainable expansion, this research investigates causes of waste and the impacts of the planned growth.

The aim of this research was to understand (1) what is considered waste, (2) where and why waste occurs in the pre-production and production stages, and (3) what the future of the Scottish salmon industry looks like. An engineering for sustainability perspective was taken with desk review research supported by inputs from observations and interviews at production sites.

At the pre-production level there are high levels of loss due to welfare issues leading to mortalities. The design and operation of the salmon farms negatively impacts local and global environmental systems. Therefore, expansion of the industry should be limited and controlled regardless of the economic growth it offers. When high levels of quality and traceability are implemented at the production levels there is limited occurrence of waste. Visual defects are influenced by the conditions in pre-production and, if present at production, products are downgraded. Discards from processing are exported and processed into an array of by-products for human and animal consumption including salmon skin crisps, fishmeal and fish oil. This is an example of industrial symbiosis and there is an opportunity for the industry to further benefit from this business approach.

Consumers and retailers have a critical role in reducing food waste and achieving global food security. By reducing their demand and accepting products with visual defects there will be less waste. Sustainable food production can only happen with consumers making more informed and diverse food choices.


Course Overview


The need to engage in better problem definition through careful dialogue with all stakeholder groups and a proper recognition of context.


An ability to work with specialists from other disciplines and professional groups acknowledging that technical innovation and business skills also must be understood, nurtured and combined as precursors to the successful implementation of sustainable solutions.


An understanding of mechanisms for managing change in organisations so future engineers are equipped to play a leadership role.


An awareness of a range of assessment frameworks, sustainability metrics and methodologies such as Life Cycle Analysis, Systems Dynamics, Multi-Criteria Decision making and Impact Assessment.