NoteDecline in abundance and health state of an Atlantic subtropical gorgonian population

- Half of the sampled Phyllogorgia dilatata colonies of Arraial do Cabo were dead.
- Tissue loss affected 75% of the living colonies and accounted for the most widespread impact.
- Disease incidence increased in southwestern Atlantic reef communities and may shape future community compositions.

Losses in coral cover have been widely reported for the Caribbean. In contrast, much less is known about the health state of the Brazilian reef fauna, which was declared as a priority for Atlantic biodiversity conservation due to its high degree of endemism. In the present study, we assessed the general health state of Phyllogorgia dilatata assemblages at the subtropical reefs of Arraial do Cabo (southeastern Brazil), where observations suggest that the abundance of this endemic gorgonian species has declined. We found that about 49% of the sampled colonies were dead, and 73% of the living colonies were affected by tissue loss. Tissue loss initially manifested as multifocal holes in the planar colonial coenenchyme and peripheral tissue retraction leaving denuded skeletal axes. In combination with other recent studies, our results raise the awareness for an increasingly threatened Southwestern Atlantic reef coral fauna.