Predator-prey-scavenging interactions between Nucella lapillus, Carcinus maenas and Eulalia viridis all exploiting Mytilus galloprovincialis on a rocky shore recovering from tributyl-tin (TBT) pollution

In 2004, a study began on a small (25 individuals) population of Nucella lapillus on the south coast of England. Following the global ban of tributyl-tin in the same year, freed from imposex, the size of the population increased such that by August 2010 it comprised > 1240 individuals. On the groyne, N. lapillus fed on barnacles (Semibalanus balanoides) up to a mean shell height of 14 mm, i.e. the first year of life. Thereafter, N. lapillus fed principally on Mytilus galloprovincialis by shell drilling. When the numbers of N. lapillus had risen significantly, a relationship with Carcinus maenas was detected, the latter feeding on M. galloprovincialis, by mandibular chipping in summer, but also consuming the remains of N. lapillus meals in winter. Further, the polychaete Eulalia viridis scavenged the remains of N. lapillus meals, both barnacles and mussels. This is the first time such feeding interactions have been identified.