Ancient fish bones reveal impacts of global warming benea...(sh were available for fisheries was a sh...)

For further information contact: Henn Ojaveer, Estonian Marine Institute, University of Tartu, Prnu, Estonia;
Tel.: +3725158328; +3724434456; e-mail: henn.ojaveer@ut.ee

Why did the fishery collapse in the Limfjord in 1830?: A long-term (1667-1860) perspective on impacts of fishing and environmental variability on fisheries for herring, eel, and whitefish in Limfjord, Denmark

The Limfjord in northern Denmark is a shallow sound which has supported commercial fisheries for centuries. In the beginning of the 19th century, the fishery declined by 90%, and fishermen went bankrupt when all the fish disappeared. What happened to all the fish?

By reconstruction of historical data series for herring, eel and whitefish the question has now been answered. We now know that both nature and humans played a significant role in the collapse.

In 1825 a winter storm broke the narrow Agger Tange isthmus, which used to separate the Limfjord from the North Sea. That led to an increase of salinity in the western part of the Limfjord. The eel population declined due to the salt water intrusion, and resulted in a 15-year long crisis for the eel fisheries before it had fully recovered. The whitefish did not survive the salinity obstacle and has never returned to the area.

The commercially most important fishery was for herring. The collapse of the herring fishery was most likely due to unsustainable fishing practices, such as fishing on top of spawning areas, eventually destroying the production rate of new young herring. Today the herring have returned to the area, but not nearly in the same numbers as they were in the early 19th century.

The study of the Limfjord fisheries provides an example of how histo
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