Tag: University College London

Fish for the City

On By suzannebirchIn Research

We’re back with new blog posts after a short summer hiatus. Our first post of the academic year (which has already begun for some of us in the US!) comes from David Orton, who is currently an Early Career Research Fellow on the EUROFARM project at University College London, where he is also a Teaching Fellow in Zooarchaeology. Here he shares research that was conducted during his previous postdoctoral fellowship at the McDonald Institute for Archaeological Research at the University of Cambridge, which was recently published in Antiquity.

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A Meta-analysis of Archaeological Cod Remains as a Tool for Understanding the Growth of London’s Northern Trade

The backstory to this research comes in two parts. First, a landmark zooarchaeological study by James Barrett and colleagues (2004) demonstrated an explosion in marine fish consumption in England within a few decades of AD1000.  Before this event – dubbed the ‘Fish Event Horizon’ (FEH) in tribute to Douglas Adams – sea fishing seems to have been rare and small-scale.

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Potential source regions and isotopic signatures for archaeological cod bones. Cross-hairs show one standard deviation ranges. Images taken from Orton et al. 2011 under CC BY license.

Second, James and his team applied stable isotope provenancing of cod bones to test whether this FEH represented a local phenomenon or the early onset of long distance trade from northern waters (full disclosure: I joined the project towards the end of this stage, in 2010). δ13C and δ15N signatures were established for six potential fishing regions using 259 samples from more than 10 countries. Applying this ‘target’ specimens from 23 (post)medieval sites around the North Sea (Barrett et al. 2011) and Baltic (Orton et al. 2011), we showed that a significant trade in northern cod existed by the 13th-14th centuries, but that the initial FEH in England primarily entailed local fishing. This raised more questions: when exactly did the trade start, how suddenly, and did the imported fish supplement or replace local catches?

Our new study, just published in Antiquity, combines a new zooarchaeological meta-analysis with the existing isotopic results to tell a clear story regarding cod imports to the city of London. Both elements rely on the same principle: that cod were traditionally decapitated before preservation for long-range trade, and that cranial elements thus normally represent relatively local catches. This allowed us to use head bones to establish regional isotopic signatures in the previous isotope work, but it also means that the cranial:postcranial ratio in consumer sites like London can be a rough index for the relative contribution of imports. We simply compiled all the raw data we could find on well-dated cod bones – almost 3000 specimens from 95 sites, including large datasets from Alison Locker and from MOLA – and plotted it using context-level date ranges.

http://creativecommons.org/licenses/by/3.0/
Stable isotopic provenancing results for 34 archaeological cod vertebrae and cleithra from various London sites (A; data from Barrett et al. 2011) set against AD 700–1700 detail of the estimated frequency distributions (B). Figure taken from Orton et al. 2014 under CC BY license.

The data show a very sudden switch to imports in the early/mid 13th C, with frequency of cranial bones dropping off just as the number of vertebrae increases sharply. This fits the isotopic results remarkably well: before about AD1250 almost all sampled specimens seem to be local; afterwards the majority are probable imports. Locally caught cod thus seem to have been substantially and rapidly replaced in Londoners’ diet by traded fish almost 800 years ago. What this meant for the local fishing industry is uncertain, but should become clearer when we look at other towns and species.

Biomolecular provenancing has a unique ability to provide direct evidence for the source of imported bones, but its cost and destructiveness ultimately limit sample sizes and hence the reliability and resolution of the stories it can tell. Integrating it with the much larger samples that can be marshalled from meta-analyses of conventional zooarchaeological data has great potential to overcome this problem.

REFERENCES

Orton DC, Morris J, Locker A and Barrett JH (2014) Fish for the City: meta-analysis of archaeological cod remains as a tool for understanding the growth of London’s northern trade. Antiquity 88, 516-530.
[link: http://antiquity.ac.uk/ant/088/ant0880516.htm%5D

Orton DC, Makowiecki D, de Roo T, Johnstone C, Harland J, Jonsson L et al. (2011) Stable Isotope Evidence for Late Medieval (14th–15th C) Origins of the Eastern Baltic Cod (Gadus morhua) Fishery. PLoS ONE 6, e27568.
[DOI: 10.1371/journal.pone.0027568]

Barrett J, Orton D, Johnstone C, Harland J, Van Neer W, Ervynck A et al. (2011) Interpreting the expansion of sea fishing in medieval Europe using stable isotope analysis of archaeological cod bones. Journal of Archaeological Science 38, 1516-24.
[DOI: 10.1016/j.jas.2011.02.017]

Barrett JH, Locker AM, and Roberts CM (2004b) The origins of intensive marine fishing in medieval Europe: the English evidence. Proceedings of the Royal Society of London. Series B: Biological Sciences 271, 2417-21. [DOI: 10.1098/rspb.2004.2885]

Chickens from Beyond the Grave

On By suzannebirchIn Research

We’re continuing our series of posts this month with a piece by Elizabeth Farebrother, who is currently working towards her PhD at University College London investigating changing animal use in Western Asia during the Neolithic and Bronze Ages. Here, she shares her MSc research, which was part of the ongoing, multidisciplinary Chicken Project. Thanks to Liz and the Chicken Project Team for contributing!

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An Integrated Faunal-centric approach to Stable Isotope Analysis at Wien-Csokorgasse Cemetery   

The integration of zooarchaeological research and stable isotope analysis can be incredibly insightful, allowing us to go beyond traditional research questions, and investigate, where relevant, socially-grounded questions from a scientific perspective. My introduction to the world of stable isotope research came through the AHRC-funded Chicken Project, and my MSc formed part of this ongoing collaborative research initiative to investigate human-fowl interaction.

Belle, a Nottingham local
Belle, a Nottingham local.

Wien-Csokorgasse – an Avar-period (6th-8th Century AD) cemetery site – is located in Vienna, Austria, and was excavated as a rescue operation in the 1970s. Zooarchaeologist Henriette Kroll carried out the faunal analysis for the site, and noted that the deposition of chickens within human burial contexts was both sexually, and hierarchically stratified; cocks were buried with males and hens were buried with females. Significantly, the length of each cockerel’s tarsometatarsus spur also corresponded with the inferred status of the human burial (Kroll, 2013).

Chicken bone is demineralised in order to extract the collagen for isotopic analysis.
Chicken bone is demineralised in order to extract the collagen for isotopic analysis.

To investigate the potential reasons for the inclusion of chickens within burials at Wien-Csokorgasse, carbon and nitrogen isotope ratios from the bone collagen of each bird were analysed and compared with the existing stable isotope study of the humans they were buried with (Herold, 2008). Prospective indicators for dietary differentiation, including biological sex, age, and cemetery chronology were explored. Perhaps the most striking result was the dietary correlation represented by δ15N values. This dietary signature would have built up in the bone collagen over differing life spans between human and chicken. To this end, the data suggest a significant overlapping period of time where each chicken may have lived alongside the human individual they were buried with.

Preliminary carbon and nitrogen isotope results for human burials and associated chickens.
Preliminary carbon and nitrogen isotope results for human burials and associated chickens.

The results of dietary stable isotope analysis were viewed through the lens of anthropological analogy, and interpretation included a diachronic survey of published and grey literature of contemporary bird iconography and bird diet in Europe. This meant that the wider social implications and behavioural patterns amongst the groups who used Wien-Csokorgasse were also considered in the study.

Acknowledgements:

Thank you to all involved in the production of this MSc dissertation. This study would not have been possible without the help and expert guidance of the AHRC-funded Chicken Project, Dr Naomi Sykes, Dr Holly Miller, Dr Henriette Kroll, the NERC Isotope Geosciences Laboratory (BGS Keyworth) and the University of Nottingham.

References

Herold, M. (2008) ‘Sex Differences in Mortality in Lower Austria and Vienna in the Early Medieval Period’ Doctoral dissertation, University of Vienna.

Kroll, H. (2013) ‘Ihrer Hühner waren drei und ein stolzer Hahn dabei: Überlegungen zur Beigabe von Hühnern im awarischen Gräberfeld an der Wiener Csokorgasse.’ in von Carnap-Bornheim, C., Dörfler, W., Kirleis, W., Müller, J. and Müller, U. (eds.) Festschrift für Helmut Johannes Kroll. Offa 69/70.