Respiration of the wedge clam <i>Donax</i> cuneatus

243-246Normal respiration was markedly reduced due to shell closure mechanism in D. cuneatus. In reduced salinities, perhaps due to the inhibition of ciliary activity of gills, the normal rate of respiration was decreased. With rise in temperature up to 34°C respiratory rate increased and declined sharply at 38°C. Oxygen debt occurred during the exposure period which was subsequently recovered in the first 6 hr after reimmersion in sea water. Inverse variation of weight specific oxygen consumption was noticed with the size of the clam. After 8 days of starvation 50% reduction in the normal respiratory rate occurred. In slight acidic medium the respiration was more whereas in slight alkaline medium it was less compared to in normal pH of the sea water. A distinct diurnal rhythm of respiration was observed; the clam consumed more oxygen at noon and less at midnight