Data for: A double edged sword: predation risk effects of a non-native species that acts as predator and prey

This data explores how a non-native species, the crab Hemigrapsus sanguineus that can act as a predator to the native prey and prey of the resident predator, impacts the risk responses of Nucella lapillus, a native snail, to its resident predator, Carcinus maenas.