On the Critical Surface Shear Strength for Japanese Littleneck Clams

In this paper, we investigate the role of geophysical environmental conditions in the self-burial activity of Japanese littleneck clams. By employing two kinds of bed material, namely, sandy soil taken from a natural intertidal flat and agar simulating cohesive soil, we performed a series of well-controlled laboratory experiments in which the clam activity was closely examined under variably prescribed geophysical conditions. The results demonstrate that irrespective of the type of bed material and exposure/submergence conditions, there exists a critical surface shear strength above which the self-burial activity becomes physically impossible. This finding may enable the performance-based assessment and adaptive management of tidal flat geoenvironments so as to conserve and restore the diverse clam activities.