Fish and Ships

Weblog of the research project "Between the North Sea and the Norwegian Sea: Interdisciplinary Studies of the Hanse"

Welcome to the weblog of the research project "Between the North Sea and the Norwegian Sea: Interdisciplinary Studies of the Hanse". The aim of the project is to investigate the economic and cultural connections of merchants from Northern German cities, such as Bremen and Hamburg with the North Atlantic islands of Iceland, Shetland and Faroe during the 15th to 17th centuries. The project is based at the German Maritime Museum (Deutsches Schiffahrtsmuseum) in Bremerhaven and funded by the Leibniz Association (2015-2018).The research is carried out by four team members, each with their individual research objectives and disciplinary background. With this blog we want to provide information about the current state of our research, and create a platform to make available results and new knowledge. Read more...

How to recognise stockfish from its bones

Bart Holterman, 22 December 2016

For most readers of our blog, probably the most mysterious part of our research is the work of Hans Christian Küchelmann, archaeozoologist, who uses archaeological finds of fish bones as traces of the late medieval North Atlantic (stock)fish trade. A fish bone found in the ground, however, does not say where the fish once came from or to which fish it belonged. So, how can one identify a stockfish merely by its bones? This blog post will shed a light on that mysterious procedure.

1. Stockfish production

Drying stockfish (rundfisk type) in Iceland. Image: Wikimedia Commons.

In order to be able to identify a stockfish bone, it is essential to know how stockfish was produced. Luckily, stockfish is made in Iceland and Northern Norway to this day in ways that have hardly changed over the centuries, so in combination with historical sources, we can reliably reconstruct what a medieval stockfish must have been like.

Stockfish is made in polar regions from fish from the Gadidae family where they are hung to dry outside during the winter. Due to climatic conditions this is only possible in arctic regions as the cool weather prevents the fish from rotting before it dries. However, the entrails must be removed before the fish is hung to dry, and the heads are cut off. This is roughly done with two methods: a) the fish is gutted and beheaded, the rest of the body left intact (rundfisk), or b) the fish is beheaded and split in two, removing the entrails as well as most of the spinal column, and then hung to dry. The latter method is called råskjær in Norwegian (rotscher in the Low German medieval documents). As this leaves only a few caudal (tail) vertebrae in the stockfish, most bones of stockfish will come from rundfisk.

2. Species and distribution

Different species of the Gadidae family used in the production of stockfish. Clockwise, starting at the top: cod (Gadus morhua), ling (Molva molva), haddock (Melanogrammus aeglefinus), pollack (Pollachius virens), tusk (Brosme brosme). images: Wikimedia Commons

Different species of the Gadidae family used in the production of stockfish. Clockwise, starting at the top: cod (Gadus morhua), ling (Molva molva), haddock (Melanogrammus aeglefinus), pollock (Pollachius virens), tusk (Brosme brosme). images: Wikimedia Commons

As mentioned, stockfish was made from species of the Gadidae family. A trained eye will have no problem recognising a bone from a Gadidae fish in most cases. Due to long travel times and the absence of freezers in pre-industrial times, these fish could only be transported in preserved form, either salted or dried. Hence, a find of a Gadidae bone, especially on inland sites, hints at having belonged to a stockfish.

However, in coastal areas these fish were also eaten fresh, so how do you know a bone is from stockfish in that case? It is necessary to look at the distribution of the different Gadidae species. Three of the species that were used for producing stockfish, namely saithe (Pollachius virens), ling (Molva molva), and tusk (Brosme brosme) do not appear in the Southern North Sea and Baltic Sea. Bones from these three species found on the European mainland, especially in inland areas, are therefore a strong indicator for stockfish.

3. Size

By far most of the stockfish, however, is and was made from cod (Gadus morhua), which does live in the Southern North Sea and the Baltic Sea. Bones of cod could therefore also belong to locally caught (and therefore not dried) fish. So we need another indicator to distinguish a stockfish from fresh local cod. The cod which live around the German shores are mostly smaller juveniles, older and larger fish live further North. By comparing the size of the bones to those of complete skeletons it is possible to estimate the size of the fish they belonged to. Bones belonging to fish larger than c. 75cm are less likely to have been local catch and were probably imported in dried form. Moreover, a high prevalence of fish in a specific size range is an indicator of stockfish, as these were sorted and sold according to size, whereas local catches will likely show a higher variety of fish in different sizes.

4. Bone composition

Because the head of the fish was cut off and remained at the production site one can expect head bones to be absent at consumption sites. Indeed, we find a clear overrepresentation of post-cranial (i.e. bones not belonging to the head, from cranium: head) bones on some sites in mainland Europe. On some archaeological sites in Iceland, for example, there are almost only cranial bones which is a clear sign that stockfish was produced there.

Archaeological finds of cod bones (brown), compared to modern bones (white). The cleithra (top) clearly belong to larger individuals and are systematically cut off on the right, indicative of stockfish production. Image: Hans Christian Küchelmann

Archaeological finds of cod bones (brown), compared to modern bones (white). The cleithra (top), which are located directly behind the head of the fish, but remain when the fish is beheaded, clearly belong to larger individuals and are systematically cut off on the right, indicative of stockfish production. Image: Hans Christian Küchelmann

5. Cutting and hammering marks

The production and consumption of stockfish can also leave traces on the bones themselves. For example, the heads of fish were chopped of in a standardised way, leaving clear-cut chopping edges on the bones of the shoulder girdle directly behind the head. Also, the preparation of stockfish required hammering the fish for a while before soaking it, to make the flesh softer. As we have seen from our own experiences in preparing stockfish, this procedure can destroy or deform the vertebrae of the fish. Hence, deformed or broken vertebrae can be a sign of stockfish consumption in the archaeological record.

6. Isotope and aDNA analysis

Further, more advanced evidence from the North Atlantic stockfish trade can be acquired by applying methods such as aDNA analysis and isotope analysis, which can potentially retrace the remains of an animal to the area in which it lived. However, an explanation of these techniques might be a topic for a next post.

Further reading

Barrett, James H. (2009): Cod bones and commerce: the medieval fishing revolution. – Current Arrchaeology 221, 20-25

Heinrich, Dirk (1986): Fishing and the Consumption of Cod (Gadus morhua Linnaeus, 1758) in the Middle Ages. in: Brinkhuizen, Dick Constantijne & Clason, Anneke T. (eds.): Fish and Archaeology.

Ólafsdottir, Gudbjörg Ásta / Westfall, Kristen M. / Edvardsson, Ragnar / Pálsson, Snæbjörn (2014): Historical DNA reveals the demographic history of Atlantic cod (Gadus morhua) in medieval and early modern Iceland. – Proceedings of the Royal Society of London B 281

Orton, David C. / Morris, James / Locker, Alison / Barrett, James H. (2014): Fish for the city: meta-analysis of archaeological cod remains and the growth of London’s northern trade. – Antiquity 88, 516-530

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Uncovering the North Atlantic trade sherd by sherd

Natascha Mehler, 12 April 2016

When it comes to the goods transported by merchants from Bremen and Hamburg to the North Atlantic islands we have only limited sources at hand. The few extant account books list the commodities they sold to the inhabitants of the islands in return for stockfish, fish oil, sulphur or woolen cloth. But the written sources are not precise but rather general and never tell where the exported goods were manufactured. To complicate matters, (archaeological) material culture of the German period is scarce. Most of the goods traded by the Germans were bulk material such as grain or flour, cloth, timber, and beer, and to a lesser extent every day items that were hard to get on the islands: horse shoes, tools, knifes, wax etc. Many of these goods, especially those of organic material, have long been gone. Ceramics, however, are a different matter. Icelanders did not produce ceramic vessels (and the Faroese and Shetlanders only to a limited extent) which means that all pots, pans, jugs and beakers needed to be imported. A considerable amount of pottery from the 15th to 17th centuries has been found in Iceland, Shetland and Faroe but what can pottery sherds tell us about that trade?

Siegburg Tórshavn

Fragments of a so called “Schnelle”, a tankard produced in Siegburg in the 16th century, found at Tórshavn, the German trading station in the Faroe islands (photograph by Helgi Michelsen).

The sherds that have survived from excavations and in museum collections in Iceland show characteristic traits of wares common in Northern Europe. The ceramic assemblages of sites such as Gautavík (a German trading site in the East), Viðey (a monastery near Reykjavík), or Stóraborg (a farm at the South coast) consist of two distinctive ware groups: stonewares and redwares. Stoneware was used to produce drinking vessels such as jugs and beakers. They were widely traded over Northern Europe, via the river Rhine and ports of Northern Germany and the Netherlands. For the trained eye, these stonewares are relatively easy to determine. The majority stems from the famous medieval and early modern production centres along the Rhine such as Siegburg, Frechen, or Cologne; a second group can be traced back to Lower Saxony.

The origin of redwares, a general term for cooking vessels (pots, pans) and plates consisting of earthenware, is far more problematic to identify. Vessel shapes and fabrics of pottery workshops are generally very similar over a large area and it is therefore hard to determine where exactly a certain redware pot was produced. Distinguishing the redwares is mostly based on typological characteristics such as a distinctive form of the rim of a pot, but the Icelandic archaeological material is often too fragmented to allow an identification beyond doubts. However, provenancing these redwares would considerably change our understanding of the trade mechanisms and pottery consumption patterns in the North Atlantic.


Fragmented redware tripod with internal lead glaze found at the trading site of Gautavík, Iceland. It dates to the late 16th century but the place of origin remains enigmatic (photograph by Natascha Mehler).

Luckily, there are other methods than typology to identify the provenance of pottery. In recent years, ICP analysis (inductively coupled plasma mass spectrometry), widely used in archaeological science, has proven to be a reliable method to determine the chemical fingerprint of the clays used for the production of ceramic vessels. ICP analysis has been applied successfully at a large number of redwares produced in Southern Scandinavia and Germany, with ground breaking work done by Torbjörn Brorsson (Kontoret för Keramiska Studier, Sweden) and Jette Linaa (Moesgaard Museum, Denmark). This means that we now have a solid base of reference material at hand which is necessary to securely identify the origin of the redwares in question. The application of the method in ceramic studies and an overview on the data reference material was presented in April 2016 at the inaugural meeting of the Baltic and North Atlantic Pottery Research Group (BNPG) which took place at the Historiska Museet Stockholm.

In summer 2016, redware fragments from selected sites in Iceland, Shetland and Faroe will be sampled in order to conduct ICP analysis. We will report on the results of the analysis, and what this means for the interpretation of the trading connections between Northern Germany and the North Atlantic islands.

BNPG Meeting 2016

Further reading:

Torbjörn Brorsson, A new method to determine the provenance of pottery – ICP analysis of pottery from Viking age settlements in Northern Europe. In: S. Kleingärtner, U. Müller, J. Scheschkewitz (eds.), Kulturwandel im Spannungsfeld von Tradition und Innovation. Festschrift for Michael Müller-Wille. Neumünster, 2013, 59-66.

Adolf Hofmeister, Das Schuldbuch eines Bremer Islandfahrers aus dem Jahre 1558. Bremisches Jahrbuch 80, 2001, 20-50.

Natascha Mehler, Die mittelalterliche Importkeramik Islands. Current Issues in Nordic Archaeology. Proceedings of the 21st Conference of Nordic Archaeologists, 6-9 September 2001, Akureyri, Iceland. Reykjavik 2004, 167-170.

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Updated workshop program!

Mike Belasus, 29 October 2015

Flyer Travel Workshop DSM

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First project workshop to take place in Bremerhaven

Natascha Mehler, 5 October 2015

The first workshop of the project takes place at the German Maritime Museum in Bremerhaven from 2-4 November 2015.

The “Travel-Workshop” is the first workshop of the interdisciplinary research project “Between the North Sea and the Norwegian Sea: Interdisciplinary Studies of the Hanse” funded by the Leibniz Association (Leibniz-Gemeinschaft) (2015-2018). The project focuses on the cultural and social links between the German cities of Bremen and Hamburg with the North Atlantic islands Faroe, Shetland and Iceland in the period c. 1400-1700.
The aim of this workshop is to bring together specialists from different disciplines and countries to shed light on several aspects of the process of travelling, and the stay of the Germans in their destination ports. The workshop is organized in two parts. The first session concentrates on the journeys: which ships were used for these journeys, what do we know about the crews, how did navigation work and which sea routes were used at that time? What were the climatic conditions and how did this affect sailing and navigation? The second session addresses questions regarding daily life on board. How was the provisioning on board and what happened when sailors fell ill? How was space on board organized? What do we know about religious life on board an on land?

Download the workshop flyer here: Flyer Travel Workshop DSM

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