Diseased coral parents can still play a vital role in coral reef restoration

Stony Coral Tissue Loss Disease (SCTLD) has caused significant damage to coral reefs in the Caribbean, leading to the death of various coral species, including Pseudodiploria strigosa, which has been particularly affected in the Mexican Caribbean.

Scientists have been exploring larval-based restoration methods to address the decline in coral abundance and colony density caused by SCTLD, despite concerns about disease transmission. A recent study published in PeerJ sheds light on the potential of using colonies affected by SCTLD for assisted sexual reproduction in the restoration of susceptible coral species.

The study, led by Sandra Mendoza Quiroz and a team of researchers from SECORE International and the Universidad Nacional Autónoma de México, examined the performance of offspring produced by crossing gametes from a healthy P. strigosa colony (with 100% healthy tissue) with those from a colony affected by SCTLD, experiencing over 50% tissue loss. The researchers compared these results with previous crosses involving only healthy parents.

Mendoza Quiroz, the lead author of the study, expressed optimism, stating that “this research provides a glimmer of hope for the conservation and restoration of species impacted by Stony Coral Tissue Loss Disease.” The findings demonstrated that even colonies affected by SCTLD can significantly contribute to the assisted sexual reproduction of susceptible species. This breakthrough has the potential to revolutionize current restoration strategies and provide a new approach to combat the devastating effects of SCTLD.

Surprisingly, the fertilization and settlement success rates of the offspring from the diseased parent colony were found to be comparable to those from previous crosses involving healthy parents. This discovery emphasizes the possibility of utilizing diseased parent colonies for assisted sexual reproduction, offering hope for the restoration of SCTLD-affected species.

The study also monitored the post-settlement survivorship of the offspring for over a year in outdoor tanks. The results revealed a survivorship rate of 7.8%, showcasing the viability and resilience of the offspring produced from the diseased parent colony.

To evaluate the long-term viability of the diseased-parent recruits, they were subsequently transplanted to a degraded reef after thirteen months. Remarkably, the recruits achieved a survivorship rate of approximately 44%, demonstrating their ability to adapt and thrive in challenging environments. The growth rate of the recruits was measured at 0.365 mm ± 1.29 SD per month, further affirming their potential for restoration efforts.

While the results are promising, the researchers acknowledge the need for precautionary measures to prevent disease transmission. Further research is necessary to understand disease resistance mechanisms and minimize potential risks associated with assisted sexual reproduction using diseased parent colonies.

The implications of this study extend beyond the Mexican Caribbean and hold broader significance for global coral reef restoration efforts. By harnessing the potential of diseased parents, scientists and conservationists can enhance their repertoire of techniques to mitigate the impacts of SCTLD and restore the delicate balance of coral ecosystems.

Source: PeerJ

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