Valérie F. Chamberland

Applying coral breeding to reef restoration: best practices, knowledge gaps, and priority actions in a rapidly evolving field

Reversing coral reef decline requires reducing environmental threats while actively restoring reef ecological structure and func-tion. A promising restoration approach uses coral breeding to boost natural recruitment and repopulate reefs with geneticallydiverse coral communities. Recent advances in predicting spawning, capturing spawn, culturing larvae, and rearing settlers haveenabled the successful propagation, settlement, and outplanting of coral offspring in all of the world’s major reef regions. Never-theless, breeding efforts frequently yield low survival, reflecting the type III survivorship curve of corals and poor condition ofmost 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 coralbreeding in restoration: (1) expanding the number of restoration sites and species, (2) improving broodstock selection to maximizethe genetic diversity and adaptive capacity of restored populations, (3) enhancing culture conditions to improve offspring healthbefore and after outplanting, and (4) scaling up infrastructure and technologies for large-scale coral breeding and restoration. Pri-oritizing 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 res-toration 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.

Date
2023
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

Assisted gene flow using cryopreserved sperm in critically endangered coral

Assisted gene flow (AGF) is a conservation intervention to accelerate
species adaptation to climate change by importing genetic
diversity into at-risk populations. Corals exemplify both the need for
AGF and its technical challenges; corals have declined in abundance,
suffered pervasive reproductive failures, and struggled to adapt to
climate change, yet mature corals cannot be easily moved for breeding,
and coral gametes lose viability within hours. Here, we report
the successful demonstration of AGF in corals using cryopreserved
sperm that was frozen for 2 to 10 y. We fertilized Acropora palmata
eggs from the western Caribbean (Curaçao) with cryopreserved
sperm from genetically distinct populations in the eastern and central
Caribbean (Florida and Puerto Rico, respectively). We then confirmed
interpopulation parentage in the Curaçao–Florida offspring
using 19,696 single-nucleotide polymorphism markers. Thus, we
provide evidence of reproductive compatibility of a Caribbean coral
across a recognized barrier to gene flow. The 6-mo survival of AGF
offspring was 42%, the highest ever achieved in this species, yielding
the largest wildlife population ever raised from cryopreserved
material. By breeding a critically endangered coral across its range
withoutmoving adults, we show that AGF using cryopreservation is
a viable conservation tool to increase genetic diversity in threatened
marine populations.

Date
2021
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao