Harnessing Coral Resilience through Nursery-to-Reef Restoration Processes Phase 2

This multi-phase project was designed to track corals through coral collection, propagation, nursery grow-out, and outplanting. This provides the foundation for developing optimal outplanting strategies for Colpophyllia natans and Diploria labyrinthiformis by evaluating whether coral that survived disease and thermal events maintain resilience during nursery grow-out and subsequent outplanting. Phase 2 of this project was divided into two sections: the continued monitoring of coral within the in-water coral nursery and post-outplanting monitoring. The outplanting was designed to evaluate the effects of shallow versus deep reef environments and proximity of a conspecific on post-outplant growth and survival.
 

Nursery monitoring found that the overall genotypic variation in Phase 1 survival persisted into Phase 2 with some changes within specific genotypes. Genetic variation was greater within C. natans compared to D. labyrinthiformis. Additionally, analysis of survival throughout Phase 1 and Phase 2 found differences in thermal sensitivity. The mortality of some genotypes was significantly affected by cumulative exposure to temperatures above 30°C whereas others showed little to no effect. Instead, some genotypes showed consistent higher mortality due to non-thermally-related factors.
 

Monitoring data suggest species specific effects of reef depth and proximity to conspecifics within the first month after outplanting. Specifically, percent living tissue of D. labyrinthiformis outplants was significantly affected by conspecific proximity and reef depth. Those corals outplanted at the shallow sites had higher percent living tissue compared to deep sites and within the corals at the shallow sites, corals outplanted closer to a conspecific had higher percent living tissue. Results represent immediate responses to the different outplant conditions rather than long-term restoration performance. Long term monitoring will allow us to make outplanting recommendations for these two species. Long-term monitoring will allow us to evaluate whether genotypic performance within the in-water nursery predicts post-outplant survival and condition.