Survival and growth of coral recruits in varying group sizes

Summary

Many corals sexually reproduce by producing coral larvae. These larvae settle in the benthos as solitary individuals but sometimes in groups of varying numbers of coral spat. However, little is known about the performance of such coral individuals in different group sizes, especially during one of the most critical stages of their life history. This paper investigated the performance of a branching coral Acropora verweyi juveniles in varying group sizes of fused coral spat by examining their survival and growth rate within 21 weeks after their settlement. Ligson et al. (2022) found out that those coral spat belonging to larger group sizes of at least six coral spat can have higher survival than their small group and solitary counterparts at least during the first few months after their settlement. They also showed that larger group sizes could immediately gain size. However, larger group sizes did not show higher growth rates within at least the first 15 weeks post-settlement. These results suggest that coral spat in larger group sizes may offer a higher chance of survival during their early stages after settlement. This outcome provides insight for improving coral sexual propagation using coral larvae for restoration. 

Significance

Coral populations experience a significant bottleneck during their early life stages, especially during few months after their settlement on the benthos. Understanding the dynamics of such process is highly relevant with the increased degradation of coral reefs worldwide. This study highlights that large group sizes of fused coral spat have better chances of survival during one of the most critical stages of their life history. Such insight widens our understanding of the ecology of coral juveniles and offers opportunities to improve our methods for coral reef restoration efforts. These research opportunities may include studies and technologies that will promote and optimize the aggregation and fusion of coral spat both in laboratory and natural reefs.

Photos

Authors:

Charlon A. Ligson (Marine Science Institute, University of the Philippines)
Patrick C. Cabaitan (Marine Science Institute, University of the Philippines)
Peter L. Harrison (Marine Ecology Research Centre, Faculty of Science and Engineering, Southern Cross University)

Read the full article: https://doi.org/10.1016/j.jembe.2022.151793