Growth of Lampsilis radiata (Bivalvia: Unionidae) in Sand and Mud: A Reciprocal Transplant Experiment

摘要: To examine the effects of habitat on shell growth and form, freshwater unionid clams (Lampsilis radiata) were reciprocally transplanted between a sandy and a muddy site in Inner Long Point Bay, Lake Erie. There were significant differences in the initial shell dimensions of the two populations, with the sand clams being larger and less obese than the mud clams. Pretransplant growth rate analysis, using annual rings, showed that long-term growth in the sand was greater than that in the mud. After 16 wk the transplanted clams were recovered. Overall growth rate was affected by the source of the clams, while transplant destination affected shape change (height growth per unit length growth). This suggests that shell growth rates may be under direct genetic control, while shell shape can be adaptively modified by environmental cues.