Internet Archaeology 7. Jones. Introduction

Introduction

The experiment here described is one of a series investigating what happens to fish bones when they are subjected to various treatments. The experiments were carried out in order to determine how fish bones can survive scavenging, trampling and other processes that occur on human occupation sites. Furthermore, it was hoped that different processes might produce characteristic damage to individual bones and may result in patterning in the assemblage. For example, trampling may be expected to affect fragile elements more than robust ones. So far, the effects of ingestion and digestion by man, pig and dog have been published (Jones 1984; 1986). Unpublished experiments have demonstrated that rats (Rattus norvegicus) readily devour fish bones, including robust large gadid bones, leaving no identifiable traces.

To investigate the effects of trampling on fish bones, cod, Gadus morhua, was selected. Bones of cod are amongst the most common marine fish remains recovered from archaeological excavations in Europe and it is clear that this species has been widely exploited as human food for many centuries, both as fresh and as dried fish. In addition to showing that cod were caught in the past, the numbers of the various elements present in archaeological assemblages have been used to try to establish if the remains of whole fresh fish or processed fish were present.

Even cursory inspection of lists of cod bones from excavations makes it clear that some elements are recorded more frequently than others. For example, the robust bones of the lower and upper jaw (dentary, articular, premaxilla and maxilla) are frequently recorded while other cranial elements, for example the metapterygoid, interopercular and urohyal, are less commonly reported. Clearly several factors account for this discrepancy. There is recovery bias which favours the larger, more robust, elements. The morphology of the bones means that some fragment into several identifiable fragments while others have only one distinctive area. Similarly, some bones are more robust than others.

Those familiar with the bones of a cod will have their own concept of which bones are robust and which fragile. The simple experiment here described is an attempt to quantify objectively the ability of different elements of the cod's skeleton to survive mechanical damage and remain identifiable for archaeological analysis.

The relative frequencies of different elements in the cod's skeleton are the only definite indicator for the presence of whole (fresh) or decapitated (preserved) fish. Discrepancies between the expected and actual number of selected cod elements have been used by a number of workers to suggest the presence of stockfish (e.g. Wilkinson 1979; Heinrich 1987).

Sometimes discrepancies in the numbers of cranial elements and post-cranial bones (including the cleithrum) have been used to indicate if dried fish (e.g. stockfish or klipfisk) were brought onto the site rather than whole fresh fish.

The purpose of this experiment is to see what patterning occurs if a cod skeleton is trampled and to imagine how such patterning might be interpreted if it were seen in an archaeological assemblage.