The Behaviour, Survival and Respiration of the CocklesCerastoderma EduleandC. Glaucumin Air

Abstract

Aspects of the physiology of the two cocklesCerastoderma edule(L.) andC. glaucum(Poiret) in air have been investigated. Both cockles exhibit bradycardia during exposure and are similarly tolerant of anoxic conditions, butC. edulesurvives longer in air thanC. glaucum. This is accounted for by the fact thatC. eduledisplays a behaviour pattern of valve movements upon emersion which allows air-breathing. Oxygen uptake rates of this cockle measured in air lie close to the lowest rates recorded in water, and are considered to approximate to a basal or quiescent level.C. glaucumdoes not air-breathe and is restricted to lowest shore levels. Values for ‘maximal’ levels of oxygen uptake in water have also been obtained together with estimates of metabolic scope for the cockle.