The Respiratory Response of Mytilus perna L. (Mollusca: Lamellibranchia) to Reduced Environmental Oxygen

Abstract

Oxygen consumption by Mytilus perna L. was measured over a range of O2 tension. The animals were able to regulate their O2 consumption down to a critical tension, below which the rate declined steeply. The critical tension differed for animals of different size, being higher for the smaller animals. However, the ventilation rate increased with reduction in the O2 tension, reaching a maximum at 70-80 mm of mercury, below which this also declined, The critical tensions for respiration and ventilation were coincident. Over a range of oxygen tension from 80 to 160 mm mercury the percentage withdrawal of O2 from the water remained constant. It is concluded that M. perna is able to regulate its O2 consumption in an environment of reduced O2 by increasing the rate at which water is passed through the mantle cavity.