Cod skulls reveal fishing patterns in the Middle Ages

Scholars from the University of Cambridge have concluded that sea fishing in northwest Europe was more locally-based than previously believed. By using skulls of cod fish, the Medieval Origins of Commercial Sea Fishing Project was able to determine that the majority of fish catches in the 10th and 11th centuries in England were from waters relatively nearby, such as the North Sea.

It was only by the 13th and 14th centuries, when local fish stocks were depleted that fisherman sailed to further seas to net the cod and other fishes that would wind up as dinner for people in urban communities such as London.


The Leverhulme Trust explained that in this project, which they funded, Dr. James Barrett of the University of Cambridge was able to use a technique known as stable isotope analysis to determine where cod were caught.

Dr. Barrett explained, “We know from various accounts – such as medieval cook books, early wood cuts, and descriptions of the way stockfish (that’s dried cod) are prepared – that almost always, when you preserve cod prior to refrigeration, you cut the head off. So it follows that skull bones are likely to be from local fishing whereas tailbones could be either from local fishing or from the dried traded product.


“This means that you can use skull bones as controls. You can compare vertebrae and fin bones to skull bones found in the same area to see if they match. If they don’t match the local skull bones, then you can look to see what skull bones they do match?”

Some early results showed that some catches did come from place further afield – for example, the fish found in the German town of Haithabu, which dated between the 9th and 11th centuries, where coming from waters off of northern Norway. But the general trend which emerged was that cod found in England and the Low Countries during High Middle Ages were usually being caught in the southern part of the North Sea.

See also: The origins of intensive marine fishing in medieval Europe: the English evidence

Source: Leverhulme Trust