MEPS 237:143-149 (2002)  -  doi:10.3354/meps237143

ABSTRACT: Spatial patterns of species body size across major environmental gradients are being quantified for terrestrial organisms, but similar efforts are largely lacking for marine invertebrates. Bathymetry represents a major environmental gradient in the oceans, and existing theoretical models predict that species body size should decrease with increasing depth, especially for deep-sea species. Previous analyses of body size in deep-sea gastropods have shown size to increase with depth and hence contradict model predictions. In this study, I use data for 636 species of gastropods (in 10 major groups) living on the NE Pacific continental shelf to test hypotheses about processes that determine size-depth trends in marine gastropods. Results show that the gastropod family Turridae, a major component of both shallow-water and deep-sea biotas, shows similar size-depth trends in both environments but that predominantly shallow water families may show different patterns. In addition, size-depth trends may differ between clades and between different trophic groups. The implications of these results for better understanding the processes that underlie bathymetric trends in body size are discussed.

KEY WORDS: Body size · Bathymetry · Gastropoda