Fish quality jeopardises the French small pelagic social-ecological system

Fish quantity has long been the most needed information for stock management as the main source of uncertainty for the fishing sector. However, as the rate of global environmental change accelerates, degradation of fish quality has become a new source of concern. Indeed, evidence is accumulating on a general decrease in fish size and fat content and on the increase of the occurrence of various contaminants. Small pelagic fishes (SPFs) are valuable food rich in fatty acids but, for this reason, are also prone to the accumulation of organic pollutants. While environmental impacts on fish quality are increasingly documented, knowledge on how these propagate to the fishing industry is still very limited. In our study we explored how the various components of the SPF French social-ecological system, from plankton to fish to fishers to the canning industry and the market, interact in their response to global change. First, by analysing the national catches of sardine and anchovy from 2000 to 2024 across the three French maritime regions, we highlighted the strong seasonal dynamics of both fisheries and the strong interannual trends over the period. Second, focusing on Bay of Biscay sardines, we revealed that on both seasonal and interannual scales, the fishing sector was caught between a bottom-up environmental control through its effects on fish quality, namely fat content and size, and a top-down control resulting from canning industry strategies in provisioning and marketing, ultimately mediated by the preferences of consumers. The fishing fleets appeared as the most vulnerable component in the system, while the processing industry appeared more flexible. Our results indicate that a decrease in fish quality can threaten an entire fishing industry. We recommend collaborative efforts between scientists and stakeholders to co-construct adaptation strategies aiming at strengthening the resilience of fisheries social-ecological systems in the face of global change.