Historic fishery collapse holds lessons for the present
The study is based on a unique dataset: a 450-year time series of herring catches in the Sound from 1200 to 1650.
A combination of climate change, overfishing, and social change caused the herring of the Sound to disappear.
German Centre for Integrative Biodiversity Research Halle-Jena-Leipzig – iDiv e. V.
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The study shows herring stock itself did shrink markedly in the 16th century, but it did not collapse completely. It was only the combined effect of several factors – environmental change, overfishing, and social change – that brought the profitable fishery to a sudden end.
view moreCredit: The University of Kiel / Schwermer
From the 13th to the 16th century, herring from the Sound – the strait in the Baltic Sea between Denmark and Sweden – was one of northern Europe’s most important trade goods. Salted herring from the so-called Skanör-Falsterbo fishery fed large parts of Europe. Around 1570, however, this fishery collapsed within a short period of time – with far-reaching consequences for trade, politics, and society. It took almost 400 years, until the 1950s, before comparable catch volumes were reached again. An international team of fisheries economists, ecologists, and historians led by Kiel University (CAU) and the German Centre for Integrative Biodiversity Research (iDiv) has now investigated why this fishery, stable for centuries, collapsed so suddenly. The results show that the collapse of the fishery cannot be explained by a simple stock collapse alone. The herring stock itself did shrink markedly in the 16th century, but it did not collapse completely. It was only the combined effect of several factors – environmental change, overfishing and social change – that brought the profitable fishery to a sudden end. The new study was published in Nature Sustainability.
“Only when you look at climate, ecology and socio-economic conditions together does a coherent picture of this historic collapse emerge", says first author Dr Rudi Voss, fisheries economist at iDiv and CAU. “None of these factors alone would have brought the fishery down. It is their interplay that explains the dynamics.”
An extraordinary time series: 450 years of fishery history
The study is based on a unique dataset: a 450-year time series of herring catches in the Sound from 1200 to 1650. It was reconstructed using fragmentary historical sources, including customs records, royal pre-emption rights (“kongekøb”), and other archival material documenting trade volumes for individual years and locations. Gaps in the data were filled using economic and ecological indicators such as the availability of salt – the most important production factor for the herring industry at the time – and reconstructed climate data. This gives the researchers a fishery dataset that extends far beyond the usual modern stock time series, which typically span only a few decades. It allowed them to study how climate change, economic crises, and overexploitation played out over decades and centuries, and to determine how these factors reinforced one another.
Interplay rather than a single cause
To reconstruct the dynamics of the fishery, the team combined two methodological approaches: a newly developed bio-economic stock assessment method (BESA), which uses historical catch and price data to estimate both sustainable catch levels and the state of the herring stock over time. In addition they used a so-called loop analysis – a method from ecology that can map complex interactions between ecological, economic and social factors within a single model, without requiring every variable to be precisely quantified. In detail: overfishing had already weakened the stock and increased fishing costs. At the same time, the onset of the “Little Ice Age” brought a period of cooling to the Baltic region, which affected the stock’s productivity and reduced it further. In parallel, social and economic conditions deteriorated: shifting dunes destroyed the infrastructure of the fishing sites, a newly imposed system of serfdom tying peasants to the land deprived the fishery of workers, and cheaper herring from the rising North Sea fishery pushed Baltic herring out of the market.
A lesson for fisheries management today
Herring in the western Baltic Sea currently lies outside safe biological limits and on the brink of collapse; a zero-catch recommendation is already in place for it. According to the authors, an interdisciplinary approach – closely combining fisheries economics, climate research, ecology, and economic history – yields more than new historical insights: these findings can also be applied directly to today’s fisheries policy. Anyone who assesses the current state of a fishery on the basis of biological stock data alone may overlook crucial risk factors. Although the focus today is on a different biological stock, what both cases share is that environmental conditions in addition to fishing pressure are hindering their recovery. Whereas a period of cooling during the “Little Ice Age” affected the stock in the past, today the warming of the Baltic Sea caused by climate change represents an additional stressor.
The study therefore supports the approach of Ecosystem-Based Fisheries Management, which takes ecological and socio-economic factors into account together – for example infrastructure, economic diversification and the social situation of fishing communities. “Looking back at history makes it clear: sustainable fisheries only succeed if we take social and economic conditions just as seriously as the state of the stock itself. That is the lesson from 450 years of herring fishing in the Sound – and it is just as relevant today as it was then,” concludes first author Voss.
Credit
The University of Kiel / Schwerme
Journal
Nature Sustainability
Method of Research
Observational study
Subject of Research
Animals
Article Title
Historic fishery collapse holds lessons for the present
Article Publication Date
28-Sep-2026
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