Stories that old oyster shells tell – part 7

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The following is the seventh instalment of an 8 part summary of the work I have been undertaking on British Native or European Flat Oyster shell specimens from archaeological and present day contexts. You can see previous posts about the shells of  Ostrea edulis Linnaeus by clicking here for the Oyster Variations category.

Two thousand years of eating oysters in the UK:

an archaeological perspective

Part 7


Oyster and other marine mollusc shells have been examined from 60 sites for this project. In addition to firmer ideas about movements of oysters between different localities in the past, and site specific information about oyster usage, in broad and brief terms, the following picture emerges about oyster exploitation in Britain.

No oyster shells seem to have been recovered from Iron Age sites. Specimens found at Owslebury in Hampshire are now believed to be incorrectly dated to that period.

Roman sites throughout the UK are renowned for the massive quantities of oysters. Contrary to assertions in the literature, no physical or documentary evidence has been found so far to indicate that the Romans introduced oyster cultivation to Britain. Although they used cultivation techniques in Italy, these would have been impractical and unnecessary in Britain. Oysters appear to have been an unexploited resource immediately prior to the Roman invasion.

The claim that oysters were transported around Britain alive in lead tanks of salt water seems also to be highly unlikely and immensely impractical. Oysters will remain fresh for up to ten days if kept cool and packed closely to prevent opening of the valves. The transport system was excellent by road, river and sea. Oysters may have been packed tight inside British made pots that were marketed to the Romans – black burnished ware pottery manufactured on the southern shores of Poole Harbour in Dorset, adjacent to abundant natural oyster beds, was sent as far afield as Housesteads on Hadrian’s Wall.

The large average oyster size for the period may reflect an abundance of mature specimens, a preference for eating larger oyster meats than we select today, as well as a rapid growth rate.

Saxon sites also produce lots of oysters but these are mostly near the coast or with easy access by river to the coast. Deterioration of the roads with the exit of the invaders and poorer organisation meant that oysters could not be sent far. Average size is slightly but significantly smaller than those from Roman sites. To date there is still no evidence for farming or cultivation of oysters.

By the Medieval period, oysters were far more widely distributed across the country. They were also very noticeably smaller. Their size tended not to be the result of selecting less mature specimens but rather a much slower growth rate. This could be attributed to temperature changes but is also likely to be a direct result of oyster relaying and storage activities. Documentary records are made about the ownership of oyster beds and oyster fishing rights. Oysters that are re-laid inter-tidally and periodically exposed at low tides cease to grow whilst out of water. Simultaneously they learn to keep the valves tight shut when exposed to the air. This ability means that they stay alive for longer when traded and dispatched. Improved longevity in keeping fresh means that oysters can be sent greater distances. The greater numbers of oysters found on coastal sites reflects their easy availability and indicates that they were a staple of the diet. The smaller numbers of oysters found at inland sites suggests that the cost of transporting them made them an occasional and luxury item for these people.

Not many oyster specimens of Post-medieval date were made available for study, so conclusions are few. The shells were smaller than in earlier periods.

The Modern period, for current purposes, is taken as including the 19th century onwards. This saw the advent of the railways and with them a cheap way of selling oysters to the masses all over the country. It was a boom time for oystermen and more and more boats went out to fish the beds. Holding pits on the shore became commonplace to store the catches before marketing. Prices of oysters plunged. They became the food of the common people everywhere, not just those living on the coast. They were so cheap that London apprentices complained of their monotonous diet of oysters and salmon.

Eventually, the oyster beds were over-fished and stocks became depleted. Efforts were made to cultivate oysters and breed foreign species. All attempts failed. The final blow to the incredibly successful oyster industry of the 19th and early 20th centuries came with massive extinctions of beds in the 1920 – thought to result from extreme cold weather and disease.

A few natural beds of oysters survived. Oysters became a luxury item on the menu again. A second catastrophe in the form of Bonamia disease decimated remaining stocks in the 1970s. This time modern technology came to the rescue of the British oyster industry by breeding oyster spat of both Ostrea edulis and Crassostrea gigas in the laboratory so that beds could be restocked. Oyster farming today with its net bags of brood oysters and floating platforms would not be recognised by our predecessors. Their methods were undoubtedly simpler but harder and we still have much to find out about them.

In the next and final part of this brief summary of the research I’ve carried out on oyster shells from archaeological deposits over an extended period of time, Part 8, looks at possibilities for future studies of this subject and provides a selection of references of work cited in this account.


N.B. Please leave a comment or e-mail me directly on if you would like to ask any questions or to have a free copy of the complete article sent to you as a pdf file. This article is just a very brief summary of my archaeological oyster research. A small selection of references to publications and reports will be provided with the article.

© Jessica Winder and Jessica’s Nature Blog, 2010. Unauthorised use and/or duplication of this material, including both text and photographs, without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Jessica Winder and Jessica’s Nature Blog with appropriate and specific direction to the original content.

 Photographs in this blog are copyright property of Jessica Winder with all rights reserved

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