Salmon fisheries are thriving industries in many places across the north, and they have been so for hundreds of years, judging from historical sources. The antiquity of this readily available nutrition source is however much less known because salmon bones – the evidence used by archaeologists to tell that these fish were part of past human diet – are very rare in northern areas.
In the whole of Finland, for example, out of thousands of Stone Age (dating 10,500–3,500 years ago) settlements, many of which were established along rivers once rich in seasonally migrating salmon, only six bones were identified in over 100 years of archaeological exploration. This situation is about to change, a new study shows.
The team of archaeologists discovered the first evidence for salmon fishing of this site through the presence of a unique mineral that forms upon combustion in the bones of migratory salmon. This mineral, containing magnesium and phosphorous, was first identified in the Laboratory for Sedimentary Archaeology at the University of Haifa, headed by Ruth Shahack-Gross, following a detailed experimental study by Don Butler, who specializes in micro-archaeology. Seeing the potential of utilizing this rare and unique mineral to advance archaeological and environmental knowledge in northern areas, the Israeli researchers partnered with Satu Koivisto of the University of Helsinki, an expert of Finnish Stone Age archaeology.
Koivisto and Butler worked with the Kierikki Stone Age Centre to excavate a fireplace inside an ancient pit-house at Kierikinkangas that included numerous tiny unidentifiable bone fragments, and together with three of the six salmon bones found across Finnish archaeology, all were analyzed back at the Laboratory for Sedimentary Archaeology in Israel.
Butler explains, “Our extensive testing of animal bones confirmed that the mineral discovered in the Kierikinkangas fireplace is the result of burning salmon bone wastes”. "With this new method, we have finally found direct evidence of the early utilization of salmon resources up north in the Stone Age,” adds Koivisto.
Shahack-Gross emphasizes, “This new finding exemplifies the strength of interdisciplinary research, as we provide here new analytical tools that are based in the natural sciences to advance archaeology”. Beyond analytics, this discovery provides brand new insights into the livelihoods of these people and the times of the year they lived at the site. The new identification of salmon utilization suggests a broader use of the estuary resource base and provides additional support for year-round occupations. "This new method opens entirely new avenues into the utilization of soil in the study of prehistoric livelihoods and diet in areas where bone materials degrade rapidly", summarizes Butler.
Butler, D.H., Koivisto, S., Brumfeld, V., Shahack-Gross, R. Early Evidence for Northern Salmonid Fisheries Discovered using Novel Mineral Proxies. Scientific Reports.
Prof. Ruth Shahack-Gross