Interpreting the expansion of sea fishing in medieval Europe using stable isotope analysis of archaeological cod bones

Archaeological fish bones reveal increases in marine fish utilisation in Northern and Western Europe beginning in the 10th and 11th centuries AD. We use stable isotope signatures from 300 archaeological cod (Gadus morhua) bones to determine whether this sea fishing revolution resulted from increased local fishing or the introduction of preserved fish transported from distant waters such as Arctic Norway, Iceland and/or the Northern Isles of Scotland (Orkney and Shetland). Results from 12 settlements in England and Flanders (Belgium) indicate that catches were initially local. Between the 9th and 12th centuries most bones represented fish from the southern North Sea. Conversely, by the 13th to 14th centuries demand was increasingly met through long distance transport - signalling the onset of the globalisation of commercial fisheries and suggesting that cities such as London quickly outgrew the capacity of local fish supplies. (C) 2011 Elsevier Ltd. All rights reserved.