Linking catch reconstructions with downstream supply chain nodes can help strengthen management actions in favour of just, sustainable and resilient futures

Supply chain opacity enables seafood fraud, human rights abuses and unsustainable resource use. To boost seafood transparency, it is vital to understand what is being caught or farmed, by whom, how, where and when. Catch reconstructions, such as those from the Sea Around Us, achieve this. Yet, linking producers’ outputs with downstream supply chain nodes (processors, distributors, wholesalers, retailers, or consumers) provides insights into who utilizes the production, its sourcing, and intended use. This paper describes a methodology for establishing links between marine taxa, producers, and downstream nodes over time. Peru is used as a case study to illustrate the approach. The resulting database covers the period between 1950 and 2021, and links 15 producers with 11 downstream nodes, across 45 functional groups (aggregating 340 taxa). A closer look at the data reveals that downstream nodes are growing increasingly reliant on inputs sourced from small-scale fisheries. Moreover, the use of unreported inputs by nodes involved in export-driven supply chains is declining, while the opposite trend is observed by nodes along supply-chains whose end consumers are domestic. Links between downstream nodes and producers are very variable and dynamic. Yet, all nodes show signs of environmental regime shifts, Fishing Down the Food Web and the expansion of fishers’ domains. The implications for supply chain transparency and fisheries systems research are discussed in detail. • Method developed to link catch reconstructions with downstream supply chain nodes. • Peru is used as a case study to illustrate the method and its applications. • Supply chains driven by the domestic market use most unreported inputs. • Small-scale producers were identified as main sources of unreported inputs. • Applications of the resulting database are discussed for combating supply chain opacity.