A herring fishery in the Sound between Denmark and Sweden collapsed suddenly around 1570 after centuries of stability, and catches did not recover to comparable levels until the 1950s, according to a study led by Kiel University and the German Centre for Integrative Biodiversity Research (iDiv), published in Nature Sustainability.
Nearly 400 years passed between the crash of the Skanör-Falsterbo fishery and its eventual rebound. For a study built partly on customs ledgers and royal purchase records, that’s a striking number, and it’s the backbone of a new analysis from an international team of fisheries economists, ecologists and historians who wanted to know why a trade that fed large parts of northern Europe fell apart so fast.
From the 13th century onward, salted herring pulled from the Sound — the strait separating Denmark and Sweden — ranked among northern Europe’s most important commodities. Then, around 1570, the fishery buckled, with consequences that rippled through trade, politics and society at the time, according to the study.
Stocks Shrank — They Didn’t Vanish
The tempting explanation is the simplest one: the fish ran out. The study complicates that story. Herring stocks in the Sound did decline sharply in the 16th century, but the population never fully collapsed. What ended the profitable fishery, according to the researchers, was the layering of three separate pressures — environmental change, overfishing and social upheaval — hitting at once.
Only when you look at climate, ecology and socioeconomic conditions together does a coherent picture of this historic collapse emerge.
Dr. Rudi Voss, fisheries economist, iDiv and CAU
Voss, the study’s first author, put it more bluntly on the interplay itself: None of these factors alone would have brought the fishery down. It is their interplay that explains the dynamics.
Rebuilding 450 Years of Catch Data
Modern fishery stock assessments typically cover a few decades. This one runs from 1200 to 1650 — 450 years — stitched together from customs records, royal preemption rights known as “kongekøb,” and other archival material tracking trade volumes at specific years and locations, the researchers said. Where the historical record went silent, the team filled gaps using economic and ecological proxies, including salt availability — the key production input for preserving herring at the time — and reconstructed climate data.
That long lens let the team watch climate shifts, economic shocks and overfishing unfold across decades and centuries rather than the handful of years most fishery data can capture, and to see how those forces fed off each other over time.
A New Tool: Bioeconomic Stock Assessment (BESA)
To turn centuries of scattered records into something analyzable, the team built a method they call bioeconomic stock assessment, or BESA. It uses historical catch and price data to estimate sustainable catch levels and the underlying health of the herring stock across the full timeline — a way of reading fish population trends through the trade ledgers merchants left behind, rather than through direct biological surveys that didn’t exist yet.
The Little Ice Age Then, Baltic Warming Now
The researchers draw a direct environmental parallel between centuries. Cooling during the Little Ice Age weighed on the herring stock in the 16th century; today, warming in the Baltic Sea driven by climate change is doing comparable damage to a different stock, according to the study. In both cases, the researchers said, environmental conditions — not fishing pressure alone — can stall a recovery.
That’s the study’s central policy argument: environmental change and fishing pressure don’t operate independently, they compound each other, and any management approach that measures only fish stocks is missing half the picture.
What Voss Says It Means for Fisheries Management Today
The study backs what researchers call ecosystem-based fisheries management — an approach that weighs ecological and socioeconomic factors together, including infrastructure, economic diversification and the social conditions of fishing communities, rather than tracking fish populations in isolation.
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.
Dr. Rudi Voss, fisheries economist, iDiv and CAU
The study, titled Historic fishery collapse holds lessons for the present,
appears in Nature Sustainability, with the identifier DOI: 10.1038/s41893-026-01937-1, according to the publication details released alongside the research.