Effects of Low Dissolved Oxygen on Juvenile Elliptio complanata (Bivalvia:Unionidae)

Through use of a closed, circulating system, we examined the effects of low oxygen on the behavior and survival of juvenile Elliptio complanata, a common freshwater clam. Clams exposed to low oxygen exhibited increased stress behavior, extending their siphons, gaping, and surfacing more often than clams exposed to higher concentrations of oxygen. Stress levels rose with exposure time and led to increased mortality in a long-term study. Low oxygen in sediments may limit juvenile survival through direct mortality and indirectly through behaviors that can lead to increased mortality. Knowledge of the limitations may prove useful in clam reestablishment programs and for regulation of management practices near existing clam beds.