Tissue mortality by Caribbean ciliate infection and white band disease in three reef-building coral species.

Alejandra Verde,Aldo Croquer,Carolina Bastidas

doi:10.7717/peerj.2196

Alejandra Verde, Aldo Croquer + Show 1 more

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https://doi.org/10.7717/peerj.2196

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Abstract

Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitude of coral hosts and are associated with rapid rates of tissue losses, thus contributing to declining coral cover in Caribbean reefs. In this study we compared tissue mortality rates associated to CCI in three species of corals with different growth forms: Orbicella faveolata (massive-boulder), O. annularis (massive-columnar) and Acropora cervicornis (branching). We also compared mortality rates in colonies of A. cervicornis bearing WBD and CCI. The study was conducted at two locations in Los Roques Archipelago National Park between April 2012 and March 2013. In A. cervicornis, the rate of tissue loss was similar between WBD (0.8 ± 1 mm/day, mean ± SD) and CCI (0.7 ± 0.9 mm/day). However, mortality rate by CCI in A. cervicornis was faster than in the massive species O. faveolata (0.5 ± 0.6 mm/day) and O. annularis (0.3 ± 0.3 mm/day). Tissue regeneration was at least fifteen times slower than the mortality rates for both diseases regardless of coral species. This is the first study providing coral tissue mortality and regeneration rates associated to CCI in colonies with massive morphologies, and it highlights the risks of further cover losses of the three most important reef-building species in the Caribbean.

Highlights

During the past few decades Caribbean coral reefs have declined partly due to the increasing prevalence of emergent and highly virulent coral diseases (Goreau et al, 1998; Harvell et al, 1999; Richardson & Aronson, 2000)
This study provides the first estimation of mortality rates in massive Caribbean coral species with Halofolliculina infection (CCI)
The results showed that ciliate infections (CCI) is more virulent in Orbicella faveolata than in O. annularis; this pattern being consistent between sites and periods of observation

Summary

Introduction

During the past few decades Caribbean coral reefs have declined partly due to the increasing prevalence of emergent and highly virulent coral diseases (Goreau et al, 1998; Harvell et al, 1999; Richardson & Aronson, 2000). Brown band (BB), skeletal eroding band (SEB) and Caribbean ciliate infections (CCI) are the ones with wider geographical distribution; the first two affecting a myriad of Indo-Pacific coral hosts (Page & Willis, 2008) and the latter affecting more than 25 out of the approximately 60 scleractinian species in the Caribbean (Cróquer et al, 2006). Ciliate infections by Halofolliculina were first reported in 10 coral species from Venezuela (Cróquer, Bastidas & Lipscomb, 2006) but soon after that it was observed throughout the wider Caribbean (Cróquer et al, 2006). Acropora palmata, A. cervicornis, Diploria labyrinthiformis, D. strigosa, Colpophyllia natans, Orbicella faveolata, O. annularis, M. franksi, Agaricia tenuifolia and Porites porites, appeared vulnerable to Halofolliculina infections (Cróquer, Bastidas & Lipscomb, 2006; Page et al, 2015). The relatively recent discovery of CCI in the Caribbean, despite disease surveys dating back to the 1970s, suggested that either the disease has recently emerged or it has been overlooked or confounded with Black Band Disease (Cróquer, Bastidas & Lipscomb, 2006; Page et al, 2015)

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