Unionacean clam dispersal in lake-to-river interfaces in Douglas Lake, Michigan.

Abstract

We investigated the distribution and abundance of clams at two river-to-lake interfaces to determine if any correlation exists between the pattern of clam dispersion and various abiotic variables; these variables are expected to be influenced by the merging of running and standing water. The results of our field work in Douglas Lake indicate that there may be optimal values for certain environmental conditions where clams are most likely to be found. Clams occur in the greatest abundance at specific ranges of temperature (22C), alkalinity (130-140 mg CaCO3/l), hardness (130-139.9 mg CaCO3/l), pH (9.0-9.49), and dissolved oxygen levels (8.5-9.4 ppm), as well as in areas where the chlorophyll concentration ranges from 0.1-.19 and 0.5-0.59 ppb and where the soil contains 0.8% organic matter.