Isotopic and historical evidence of regional stockfish trade in the Skagerrak during the 16th century

Preserved fish was one of the main traded commodities in medieval and early modern times, and herring and cod were the socioeconomically most important species. This paper brings together stable isotope ratio analysis of archaeological cod bones and documentary data from customs records originating from the early modern Swedish town of Nya Lodose (1473-1624 CE), shedding new light on the import of stockfish (dried cod). The combined results show that the stockfish imported to Nya Lodose was mainly produced in the Danish town of Skagen, and the importance of Bergenfish was negligible. The Skagen fisheries targeted large gadids, skates, and flatfish and have hitherto been bypassed in archaeological research on the medieval and early modern fish trade. The findings of this research highlight the intense connectivity between communities across the Skagerrak and give an example of the comprehensive regional fish trade that existed alongside the long-distance trade. Another important conclusion is that the isotopic values for cod caught in the Skagerrak must be used with caution since this sea basin is populated by several different cod stocks. The North Sea cod population inhabits a large part of the Skagerrak, and cod bones with isotopic values consistent with the North Sea might thus have been fished in the Skagerrak.