An historic fishery collapse driven by socioeconomic and environmental factors

In the Late Middle Ages, the western Baltic herring fishery played a central role in Europe. Salted herring was the basis for welfare and political power. We make use of a 450-year time series of Baltic herring catches (1200–1650), to identify which factors drove the herring catch dynamics during different phases of our time series. By the year 1570, the fishery suddenly collapsed, causing large-scale dislocations in trade, with major social and political consequences. Using a recently established bioeconomic stock assessment method based on catch and price data, in tandem with a loop analysis, we find that a combination of climate change, overfishing and socioeconomic factors can explain the drastic collapse of the fishery. The results underline the need for interdisciplinary approaches, including social sciences, to understand the dynamics of fishery systems. This has relevance for fisheries management today, in the Baltic and elsewhere.