Proxy Measurements of California Mussel Valve Length

Abstract

Archaeologists studying shell assemblages from prehistoric sites along the Pacific coast of North America have been interested in the influences of collecting intensity and environmental variability on California mussel (Mytilus californianus) size. To determine the variation in mussel size within a shell assemblage, researchers have developed a variety of proxies of mussel valve length based on measurements of morphological features occurring at or near the valve’s umbo. We propose four additional measurements that can serve as proxies and evaluate their correlation with valve length using regression analysis. Of the four, anterior adductor scar length has the strongest correlation, and we present two examples of its application. We also evaluate a popular visual technique based on a set of outline drawings of valves of varying lengths, and we found that it systematically underestimated valve length but could be useful under certain circumstances. We conclude that the selection of a particular proxy of mussel valve length depends on the nature of the mussel shell assemblage being studied and the research context.

Middle to Late Holocene near-shore foraging strategies at Caution Bay, Papua New Guinea

“…Linear morphometric analyses have been successfully implemented to predict original shell size, with these data often fed into explorations of resource depression or resilience stimulated by human predation or environmental change (e.g. Ash et al, 2013;Campbell and Braje, 2015;Faulkner, 2010;Glassow et al, 2016;Thangavelu et al, 2011;Yamazaki and Oda, 2009). Importantly, a number of researchers have highlighted the need to consider the complex interaction of natural and cultural processes that can stimulate shifts in size and/or age structure in mollusc assemblages beyond human exploitation alone (e.g.…”