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Reversing coral reef decline requires reducing environmental threats while actively restoring reef ecological structure and function. A promising restoration approach uses coral breeding to boost natural recruitment and repopulate reefs with genetically diverse coral communities. Recent advances in predicting spawning, capturing spawn, culturing larvae, and rearing settlers have enabled the successful propagation, settlement, and outplanting of coral offspring in all of the world's major reef regions. Nevertheless, breeding efforts frequently yield low survival, reflecting the type III survivorship curve of corals and poor condition of most reefs targeted for restoration. Furthermore, coral breeding programs are still limited in spatial scale and species diversity. Here, we highlight four priority areas for research and cooperative innovation to increase the effectiveness and scale of coral breeding in restoration: (1) expanding the number of restoration sites and species, (2) improving broodstock selection to maximize the genetic diversity and adaptive capacity of restored populations, (3) enhancing culture conditions to improve offspring health before and after outplanting, and (4) scaling up infrastructure and technologies for large‐scale coral breeding and restoration. Prioritizing efforts in these four areas will enable practitioners to address reef decline at relevant ecological scales, re‐establish self‐sustaining coral populations, and ensure the long‐term success of restoration interventions. Overall, we aim to guide the coral restoration community toward actions and opportunities that can yield rapid technical advances in larval rearing and coral breeding, foster interdisciplinary collaborations, and ultimately achieve the ecological restoration of coral reefs.
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Multi‐year evaluation of rearing techniques for three sexually propagated Caribbean corals in a restoration setting
In response to declining coral populations worldwide, conservation groups are increasingly applying restoration strategies to bolster abundance and diversity, including sexual propagation of corals. Collection and fertilization of coral gametes as well as larval rearing and settlement have been successful. However, post‐settlement stages remain a bottleneck (80–100% mortality), which makes this technique costly to implement at scale. To address this challenge, we compared the survival and colony size of three sexually propagated Caribbean coral species,Diploria labyrinthiformis,Pseudodiploria strigosa, andOrbicella faveolata, reared at three levels of investment: direct outplant to reef, in situ field nursery rearing, and ex situ aquaculture facility rearing. As part of coral sexual propagation work in St. Croix, United States Virgin Islands, recruits were reared for 1 year before being outplanted to reef plots and were monitored annually for three subsequent years. The cost‐effectiveness of each rearing strategy was calculated at each monitoring time point via coral seeding unit yield and cost per seeding unit. Although survival was low at 4 years (0–1.8%), corals reared in the in situ nursery displayed significantly higher survival and therefore lower cost per seeding unit than the other two investment strategies. These results highlight the benefits of an in situ nursery stage to increase long‐term juvenile survival and cost‐effectiveness. The return on investment of corals reared in the in situ nursery suggests that outplanting sexually propagated corals may be a viable restoration strategy; however, the low proportion of corals surviving at 4 years highlights current limitations when outplanting on degraded reefs.
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- PAR ID:
- 10581183
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Restoration Ecology
- Volume:
- 33
- Issue:
- 4
- ISSN:
- 1061-2971
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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