Eastern Oyster Recruitment Patterns on and Near Natural Reefs: Implications for the Design of Oyster Reef Restoration Projects

Abstract

The spatial relationship between adult eastern oyster Crassostrea virginica populations and recruitment to the benthos of their offspring is not well understood. It is well established that larvae can be widely dispersed, but the relationship between dispersal potential and actual recruitment patterns across the full range of spatial scales involved remains unknown. To explore this relationship, spat collectors were deployed on and near (up to 1 km distance) three natural oyster reefs in New Hampshire in 2014 and 2015. Spat densities on the reefs and within 400 m of the reefs were nearly 10-fold higher than densities more distant. These data do not negate the potential importance of widespread dispersal and recruitment, but they do indicate a surprising level of recruitment very near their likely source. Additional research is needed in other areas to test the generality of the findings and to assess potential causal factors for the observed patterns. The overall implication for choosing sites for oyster reef restoration projects, particularly in recruitment-limited areas, is that they may need to be located much closer to spawning adults than previously thought to maximize the likelihood of adequate natural recruitment and reef development.