Carbon and nitrogen stable isotope values in freshwater, brackish and marine fish bone collagen from Mesolithic and Neolithic sites in central and northern Europe

The aim of this research is to examine the isotopic characterisation of archaeological fish species as it relates to freshwater, brackish and marine environments, trophic level and migration patterns, and to determine intraspecies variation within and between fish populations in different locations within central and northern Europe. Carbon and nitrogen stable isotope analysis was undertaken on collagen extracted from 72 fish bone samples from eight Mesolithic and Neolithic archaeological sites in this region. Thirty-six (50%) of the specimens analysed produced results with acceptable carbon to nitrogen atomic ratios (2·9–3·6). The fish remains encompassed a wide spectrum of freshwater, brackish and marine taxa (n = 12), which were reflected in the δ13C values (−24·5 to −7·8‰). The freshwater/brackish fish (pike, Esox lucius; perch, Perca fluviatilis; zander, Sander lucioperca) had δ13C values that ranged from −24·2 to −19·3‰, whereas the brackish/marine fish (spurdog, Squalus acanthias; flatfish, Pleuronectidae; codfish, Gadidae; garfish, Belone belone; mackerel, Scomber scombrus) ranged from −14·9 to −9·4‰. Salmonidae, an anadromous taxon, and eel (Anguilla anguilla), a catadromous species, had carbon isotope values consistent with marine origin, and no evidence of freshwater residency (−12·7 to −11·7‰). The δ15N values had a range of 6·2‰ (6·5–12·7‰) indicating that these fish were on average feeding at 1·7 trophic levels higher than their producers in these diverse aquatic environments. These results serve as an important ecological baseline for the future isotopic reconstruction of the diet of human populations dating to the late Mesolithic and early Neolithic of the region.