Point Conception, California, has long been recognized as an environmental transition zone for both terrestrial and marine life forms occupying central and southern California. Recent archaeological investigations above and below Point Conception have revealed a number of differences in the archaeological records of the respective regions. Late Period coastal middens north of Point Conception contain higher densities of shellfish remains and smaller quantities of fish and sea mammal remains than coastal midden deposits along the Santa Barbara Channel to the east, where Late Period sites contain substantial quantities of fish and sea mammal remains. These differences in the archaeological records appear to be determined, in large part, by differences in the relative resource abundances in the two regions. However, to understand more completely the variability in subsistence strategies, one must go beyond simply documenting differences in food resource abundance in the environment. It is proposed that the economics of resource exploitation must be considered in the formulation of any adequate explanation of resource variability.