# The Role of Live and Dead Corals in Shaping Fish Assemblages Across Life Stages

## TL;DR

The study shows that while dead corals can temporarily shelter young fish, live corals are crucial for supporting diverse and abundant fish populations, emphasizing the need for restoration strategies that include both.

## Contribution

The study introduces a novel approach by examining the roles of live and dead corals on reef fish assemblages across life stages in a degraded reef environment.

## Key findings

- Dead coral structures provide similar shelter for mobile recruits as live corals.
- Live corals support higher post-recruit abundance, species richness, and functional diversity.
- Live corals are essential for long-term biodiversity and functional trait diversity in reef fish.

## Abstract

Coral reef fishes face unprecedented threats, as extensive habitat degradation compromises their ecological functions by modifying assemblage structure. It remains unknown how resistant reef fishes are to widespread losses in coral cover, and most studies tend to focus on adults, overlooking the important role of recruits. This study employed taxonomic and trait‐based approaches to investigate how live and dead branching corals influence reef fish assemblages across life stages. Over 1 year, we monitored recruitment and the migration of post‐recruits (juveniles and adults) on manually constructed 1 m2 patches of live and dead branching corals in a degraded reef. Recruit assemblages, composed mainly of two trophic groups, exhibited similar abundance and richness in the complex structures of dead and live coral patches, compared to flat control patches. Conversely, post‐recruit fishes were more abundant, species‐rich, and functionally diverse in live coral patches, encompassing several trophic groups and displaying a dominance shift between mobile and sedentary species. Our findings reveal that while dead coral structures can serve as temporary shelters for mobile recruits, live corals are essential for supporting long‐term biodiversity and diverse functional traits. This study underscores the complementary roles of both live and dead corals in promoting reef fish recovery and highlights the value of integrative strategies for reef ecosystem restoration.

We assessed the effects of experimental patches of live and dead corals on reef fish assemblages in different live stages. While dead and live corals provided equal shelter for mobile recruits, only live corals supported higher post‐recruit abundance, species richness, and functional diversity. These findings highlight the complementary roles of live and dead corals in fish recovery and stress the importance of integrative reef restoration strategies.