Incremental Growth Structures in Nile Fish and Molluscs from Archaeological Sites as Indicators of Holocene Environmental Change in Egypt

Abstract

Incremental growth structures of fish and molluscs have been used as palaeoenvironmental indicators for nearly two decades, but the validity of the method's underlying assumptions has not been fully explored, particularly with regard to the use of fish remains. Towards this goal, the basic assumption-that annulus width is correlated with changing temperature-is reviewed and a test on two species of Nile fish ( Lates niloticus and Clarias spp.) is conducted to investigate the validity and limits of the method. Using the geological record of Holocene environments in Egypt as a standard for comparison, results suggest that incremental growth of the tested species is a reasonable measure of local environmental conditions over periods of time represented by the collective life span of the studied individuals. The environmental changes inferred by this study, in turn, appear to be correlated with changes in human subsistence and settlement patterns in the western desert of Egypt and the Nile valley.