The Ecology of Lough Ine XVI. Predation and Diurnal Migration in the Paracentrotus Community

Abstract

Observations and experiments on predation have confirmed that Marthasterias will destroy Gibbula cineraria and Anomia ephippium. Occasional destruction of Paracentrotus at the upper margin of its distribution is attributed to birds. Remains of crabs, especially Carcinus. are found in middens, left presumably by birds. Herring gulls have been seen to attack starfish in the shallow sublittoral. Paracentrotus and Gibbula come up onto the tops of boulders by day; Marthasterias (and crabs) come out by night. We suggest that the system of diurnal migrations tends to separate prey from predator, so that populations of each may survive. Diversity of habitats also favors general stability.