Shellfish exploitation during the Oakhurst at Klipdrift Cave, southern Cape, South Africa

Kokeli P Ryano,Christopher S Henshilwood,Sarah Wurz,Karen L Van Niekerk

doi:10.17159/sajs.2019/5578

Abstract

Klipdrift Cave in the southern Cape, South Africa, provides new insights into shellfish harvesting during the Later Stone Age (14–9 ka) period associated with the Oakhurst techno-complex. Two shellfish species dominate: Turbo sarmaticus and Dinoplax gigas. An abrupt shift in the relative frequencies of these species occurs in the middle of the sequence with T. sarmaticus almost completely replacing D. gigas. The shift in dominant species is likely due to environmental change caused by fluctuating sea levels rather than change in sea surface temperatures. The shellfish assemblage shows that local coastal habitats at Klipdrift Cave were somewhat different from those of contemporaneous sites in the southern Cape. Although the shellfish specimens are smaller at Klipdrift Cave than those from Middle Stone Age localities such as Blombos Cave, there is no robust indication that larger human populations at Klipdrift Cave during the Oakhurst period might have caused this change in size. Environmental or ecological factors could have restricted shellfish growth rates as some experimental works have suggested, but this possibility also remains to be further explored. Significance:  The dominance of D. gigas and T. sarmaticus at Klipdrift Cave is surprising, as it indicates a local habitat slightly different from other similar sites during the Oakhurst period. The shift in dominance from D. gigas to T. sarmaticus indicates changing climatic and environmental conditions during the Oakhurst period, 14–7 ka.

Highlights

Evidence for the exploitation of shellfish for subsistence traces back to at least 164 ka during the Middle Stone Age (MSA) in South Africa[1], and by 100–60 ka shellfish were systematically and intensively exploited at a handful of sites[2,3,4,5]
We address two main issues here: first, whether the change in shellfish species over time at Klipdrift Cave (KDC) could be attributed to climate, environment and/ or human choices; and second, whether human agents were responsible for the differences in the shellfish sizes observed at KDC
Of the 11 mollusc species that occur at KDC, 2 are dominant: D. gigas is abundant in the lower layers while T. sarmaticus is more numerous upwards

Summary

Introduction

Evidence for the exploitation of shellfish for subsistence traces back to at least 164 ka during the Middle Stone Age (MSA) in South Africa[1], and by 100–60 ka shellfish were systematically and intensively exploited at a handful of sites[2,3,4,5]. Evidence for shell-fishing re-appears at around 14 ka in the southern Cape,[9] at the end of the period associated with the Robberg techno-complex. Shellfish become more abundant in sites during the subsequent period linked to the Oakhurst techno-complex, around 14–7 ka, sites from this period with shellfish are still relatively uncommon.[10,11] The most abundant evidence for intensive shellfish exploitation comes from the ‘megamidden’ period, between 3 ka and 2 ka, from the West coast, which is dotted with extensive open shell middens.[12]

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Discussion

Conclusion