Balanus and Chthamalus species of barnacles are sessile arthropods native and abundant in the intertidal zone along the California coast. Due to environmental and physiological factors, barnacles have variable survivability at different tidal elevations. Urosalpinx cinerea, the Atlantic oyster drill, is an invasive species whose predation patterns can manipulate the zonation of native populations causing substantial local impacts. The effects of tidal elevation on Ostrea lurida (the Olympia oyster) predation by drills is a well-studied example. Drills killed about 60% of adult oysters at +7.0cm MLLW within 2 months while oysters at +37cm were not preyed upon (Kiriakopolos et al. 2014). Although they are not of conservation concern, barnacles are the preferred prey of drills and hold a utility in studying the patterns of drill predation based on tidal elevation. Barnacles and O. lurida have similar life history characteristics: they share a common predator, both are intertidal inhabitants that begin as free swimming a larvae and mature into sessile adults, both are filter feeders, and both have a somewhat similar breeding season. Our short-term barnacle recruitment data provides insight to possible predator-influenced presettlement behaviors whereas our survival data sheds light on post-settlement mortality patterns based on tidal elevation that may be related to drill zonation. The results of this experiment may provide insight to the ecological pressures experienced by O. lurida while raising additional questions regarding restoration efforts
