Spat cockles, C. edule L., settled at the top of the shore so cockles were abundant there. The cockles at the bottom of the shore were all old and had been washed down the shore. At the top of the shore cockles were abundant, young and slow growing; at the bottom they were scarce, old and fast growing. Mean size thus increased down the shore and was inversely correlated with cockle density. The flesh content for a given sized cockle increased down the shore and was inversely correlated with cockle density. Such variation in cockle size and flesh content may affect the predator''s response to cockle density.