The Contribution of Small Individuals to Density-Body Size Relationships

The relationship between density and body size is central to our understanding of species assemblages. The greatest challenge in sampling complete assemblages is obtaining reliable estimates of all taxa regardless of body size. We therefore examined the density-body size relationship in a coral reef fish assemblage using a novel sampling method which permits reliable quantification of the small/cryptic reef fish fauna. We found a negative linear relationship between density and adult body size. This is in marked contrast to the polygonal relationship previously described for other local scale assemblage studies. Our linear relationship may be a consequence of the larger differences in body size among taxa. Spanning over five orders of magnitude, the range of body sizes appears to be an important factor in shaping density-body size relationships.