Role of Predators in the Recruitment of Subtidal Invertebrates in the Southwest Bay of Fundy, NB

Predation is believed to be one of the most influential sources of early post-settlement mortality of benthic marine invertebrates, but previous studies of predator influences on juveniles have shown conflicting results.  The objective of this study was to investigate possible predation effects on developing invertebrate communities in cobble-filled collectors at two subtidal sites in the southwest Bay of Fundy, Canada.  Three predator treatments were designed:  the first excluded 7-50 mm predators (e.g. fish, decapods, urchins), the second allowed access by predators <50 mm, and the third tested for caging artifacts caused by the mesh.  Results from both sites indicated that there was no effect of predator exclusion on the average abundance, richness, and diversity of the prey community, despite a reduction in the abundance and biomass of large predators.  Differences in the prey community between the access treatment and the other two treatments likely resulted from a mesh effect.