The Prehistory of Intensive Sea Fishing

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The Prehistory of Intensive Sea Fishing
Dr. James Barrett McDonald Institute for
Archaeological Research
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Why Study the Early Development of Sea Fishing?

• Implications for social and economic history
• Implications for historical ecology

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Todays Objectives

• To dispel two opposing popular misconceptions
  modernity and the static past
• To introduce the archaeological study of fishing
• To illuminate the early growth of intensive sea
  fishing in Northern and Western Europe focusing
  on cod as a case study
• To introduce efforts to detect any associated
  early impacts on marine ecosystems

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In the Beginning The Mesolithic
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Stable Carbon Isotopes Show Changing Dietary
Importance of Marine Protein
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High Reliance on Marine Protein Doesnt Reappear
until the Middle Ages
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Scandinavia The Exception to the Rule?

• Catching and eating cod, herring and related
  species part of daily routine throughout
  prehistory

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Sea Fishing in Atlantic Scotland

• Very little fishing before the Viking Age
• Intensification in the 9th 11th centuries

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Quoygrew Chronology
Top of marine zone
11th 12th century
Base of marine zone
10th century
Base of Viking Age midden
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The Fish Middens of Atlantic Scotland
Roberts Haven
St Boniface
Quoygrew
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Dried Cod Production
Removing the anterior vertebrae
Decapitation

• Based on cut marks and element distributions
• Similar cut marks occur on possible imported
  specimens around the Baltic and North Seas.
  Stockfish trade?

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England

• Very little sea fishing until near the end of the
  first millennium
• Rapid expansion of cod and herring fishing within
  a few decades of AD 1000 the fish event horizon
• Continued intensification over the long term,
  with increasing diversity of species exploited
  and expansion to new fishing grounds (e.g.
  Iceland and Newfoundland)

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The York Sequence
n13517, derived from sieving only
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York Butchered Cod Vertebrae

• Transverse cuts typically used as evidence of
  stockfish production, caused when severing the
  vertebral column to remove the head and anterior
  vertebrae

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Ribe, Jutland, DenmarkCod Size Distribution by
Date
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Cod Provenance Control Samples

• Possible to distinguish approximate location of
  catch using reliable stable isotope analyses

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Causal Variables

• Temperature
• Salinity
• Length and type of food web in each area, and
  consequent trophic level of cod

TL
temp
salinity
salinity
TL
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Cod Provenance Target Samples

• Arctic Norwegian cod at Hedeby (9th-11th
  century)?
• Traded cod at Wharram Percy (13th century)?
• Local dried cod production in the Baltic (15th
  century)

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Uppsala, Sweden13th Century Vertebrae

• All appear to be imports from Arctic Norway or
  the North Sea

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Uppsala, Sweden 14th-15th Century

• All but one specimen appear local

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Poland 13th-14th Century Vertebrae

• All appear to be imports, perhaps from Arctic
  Norway

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Poland 14th-15th Century

• All but one specimen appear local

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Estonia Late 13th-14th Century

• All appear to be imports, perhaps from the North
  Sea

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Commercial Fishing Potential Drivers

• Environmental
• The Medieval Warm Period (increased agricultural
  production population)
• Human impacts on freshwater ecosystems
• The MWP may also have increased cod herring
  abundance in northern fishing grounds a
  Butterfly Effect

• Socio-economic
• The Viking Age diaspora
• Rapid urban expansion
• The development of long-range trade in staple
  goods (cf. ship capacities)
• Changes in Christian fasting practices (e.g. the
  Benedictine reform of c.970)

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But can we detect the impact of this early
commercial fishery on marine ecosystems?
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Bait Collection at Quoygrew, Orkney
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Roberts Haven Saithe
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Long Term Human Impacts?A North Sea Example
S. North Sea Modern d15N
N. North Sea Modern d15N

• Downward shift in trophic level between past and
  present?
• Eutrophication of S. North Sea evident in Middle
  Ages?

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Acknowledgements

• Social Sciences and Humanities Research Council
  of Canada
• Society for Medieval Archaeology
• York Archaeological Trust
• Project collaborators especially Jennifer
  Harland, Cluny Johnstone, Anton Ervynck, Michael
  Richards and Wim Van Neer

• Leverhulme Trust
• Historic Scotland
• British Academy
• Census of Marine Life
• English Heritage
• Heritage Lottery Fund
• History of Marine Animal Populations
• McDonald Institute for Archaeological Research