Surf ’n turf
The research, which is published in the December issue of the Journal of Archaeological Science-Reports, is based on isotopic research of 56 human bones from the North Sea, conducted by the university of Groningen and the ‘Doggerland Research Group’, a collective including the National Museum of Antiquities (RMO), the Cultural Heritage Agency (RCE), Stichting ‘Stone’ for Stone Age research in the Netherlands and the municipal archaeologists of Rotterdam (BOOR). The results demonstrate that the menu of the ‘Doggerlanders’ over a period of 4000 years, roughly between 9500 and 6000 cal BC, gradually changed from terrestrial to aquatic, or… from a regular steak to mostly fish. Freshwater fish occurred mostly on the menu as well as associated species such as waterfowl, otter and beaver.
The research is based on the analysis of stable isotopes, in particular carbon and nitrogen. These are variants of atoms with a distinct basic value. These differ according to the trophic level of the consumer and whether they live in an aquatic reservoir and make use of its resources. The raised levels of the bones dating to the Mesolithic (N=33) clearly pointed to a dominant contribution of freshwater resources. At the same time the researchers were able to discover a trend over time. This was not straightforward since the dates of the Mesolithic bones suffer from the so-called reservoir effect, which is an offset between the levels of C14 in water and the atmosphere. This means that all the bones are up to several hundred years too old. Due to the fact that the bones were dredged from the North Sea and are without a direct archaeological context it was not possible to calibrate this effect, yet their relative age and the fact that they pre-date the inundation of Doggerland makes them all Mesolithic and made it possible to discover a statistically relevant trend from terrestrial to aquatic resources over time. Of course this does not mean that an occasional deer or boar was not shot, but it was mostly fish that was on the table.
Living in a drowning landscape
The trend that was discovered in the composition of the Doggerland-menu is strongly related to the fact that this area gradually drowned following the last Ice Age. Between 9500 and 6000 cal BC sea levels rose about two metres per century on average (which is about ten times the current rate!). The low-lying North Sea basin gradually flooded. It was often thought that this drowning land and the encroaching coast-line forced people further inland or made them change towards a marine diet. The isotopic values rather demonstrated a different scenario. Although there are some bones with a marine signal the majority point to the increased consumption of freshwater fish and related resources. This indicates that people, rather than abandoning this increasingly wet area stayed where they were. Instead of abandoning their homelands, they changed their ways and traditions and adapted to the developing wetlands that arose around them in the delta areas of Meuse, Rhine and Thames. This is actually far from strange as freshwater wetlands rank amongst the most rich areas in food sources world-wide.
Treasure trove in front of our coast
The bones that were used in this research come from the North Sea, which yielded many prehistoric finds over the last years. The finds are not only from fishing nets, but actually mainly derive from beaches and large infrastructural projects such as the Tweede Maasvlakte (a large harbour extension near Rotterdam) and the Zandmotor (an artificial beach replenishment reservoir). The sand that is used for these projects originates several kilometres from the Dutch coast and harbours the remains of this largely undiscovered prehistoric landscape. While research with divers at the original sites is difficult, the finds and these scientific results indicate the quantity and quality of the data that is available. These are more than individual finds without context, but they actually derive from sites and locations where parts of the prehistoric lansdcape is likely preserved intact. This makes it worthwhile to investigate and protect these areas.
The National Museum of Antiquities
In collaboration with its partners the National Museum of Antiquities in the Netherlands conducts reseach into the Stone Age of the North sea and curates and displays many objects of this lost landscape. It actively involves the public in reporting these finds and records them.
Past Horizons. 2016. “Ancient Doggerland diet discovered”. Past Horizons. Posted: November 10, 2016. Available online: http://www.pasthorizonspr.com/index.php/archives/11/2016/ancient-doggerland-diet-discovered