Ancient DNA reveals the Arctic origin of Viking Age stockfish from Haithabu, Germany. Ancient DNA from Viking Age fish

Knowledge of the range and chronology of historic trade in natural resources is essential for determining the impacts of past human activities on marine environments. However, the specific biological sources of such trade are often difficult to identify using archaeological methods alone, in particular if species have a wide spatial distribution and lack clear morphological differentiation between populations. Here, we report that ancient fish-bone remains, despite being porous, brittle and light, provide an excellent source of endogenous DNA –of sufficient quality for whole genome reconstruction. By comparing ancient genome sequence data to that of modern specimens, we determine the most likely biological origin of multiple Viking-Age (800-1066 CE) and subsequent medieval (1066-1280 CE) Atlantic cod (Gadus morhua) bones from excavation sites in Germany, Norway and the United Kingdom. Archaeological context indicates that one of these sites was a fishing settlement for the procurement of local catches, whereas the other localities were centers of trade. We find that fish from the trade sites show a mixed or entirely non-local origin, with Viking Age samples from Haithabu, Germany being traced back to the North East Arctic Atlantic cod population that has supported the iconic Lofoten fisheries of Norway for centuries. By providing evidence of an Arctic origin, our results solve a long-standing controversial hypothesis and indicate that the marine resources of the North Atlantic Ocean were used to sustain an international demand for protein as far back as the Viking Age.