Rate of Growth of Cardium edule

Abstract

IN September 1932 the New Brighton (Wallasey) Corporation began an excavation of the sandy foreshore near high-water mark, which was completed and filled with sea-water in May 1933 to form an artificial marine lake. Water is retained in the lake by a sea-wall, which is, however, covered on good spring tides (that is, 29 ft. or more), when the water in the lake is refreshed and partially renewed. The bottom of the lake was originally sand, but had acquired a considerable deposit of mud by february 1935, when the water was run out for removal of encroaching blown sand. At this time, the cockle, Cardium edule, was found in considerable numbers (33–459 per sq. metre), as determined by M. Davies, E. Norman, G. E. Williams, P. E. Travis, K. C. Fulton and one of us (J.H.O.) in the sand and mud in the exposed bed, the cockles having entered the lake after the final filling on May 9, 1933.