Spatial Patterns of a Lethal White Syndrome Outbreak in Pseudodiploria strigosa

Edgar O Guzmán-Urieta,Eric Jordán-Dahlgren

doi:10.3389/fmars.2021.669171

Edgar O Guzmán-Urieta, Eric Jordán-Dahlgren

Open Access

https://doi.org/10.3389/fmars.2021.669171

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Abstract

We analyzed the spatial distribution patterns of a white syndrome (WS) outbreak affecting Pseudodiploria strigosa colonies in the northern Mexican Caribbean during 2018–2019. The purpose of the study was to describe the outbreak progression in a single species and determine if this WS incidence is related to the nearest diseased neighbor distance. Two separated sites with different P. strigosa colonial densities (Bocana: 0.08 col/m2; Picudas: 0.2 col/m2) were selected in similar habitats of the same reef complex. P. strigosa colonies within the survey sites were mapped, and their status was recorded (healthy, diseased, or dead) in sequential surveys until colonies died or the study terminated (306 days). Spatial distribution modes were assessed using Ripley’s K function. The spatial colony distribution was random in one site (Bocana) and clustered in the other (Picudas). However, the WS disease incidence per survey was randomly distributed in both sites throughout the observation period of the outbreak, suggesting that WS transmission at small spatial scales was independent of the colony distribution pattern and from the nearest diseased colonies. Survival probability since WS onset in surveyed colonies was different: 0% at Bocana and 14% at Picudas by April 2019. But, eventually, all diseased colonies died in both sites. WS outbreak timing was different at the two sites: Initial prevalence 8% at the Bocana site vs. 44% at Picudas site. Distribution of time to disease onset shown multimodality, with modes varying from 17 to 184 days and wide main modes amplitude suggest a highly variable resistance to the WS. Disease incidence was not abated during winter surveys. Differences between sites in the WS disease outbreak distribution and progression suggest that colony condition, environmental quality, and perhaps several transmission events played an essential role in the complex outbreak dynamics at the local spatial scale of our study.

Highlights

In recent years outbreaks of a lethal white syndrome (WS) affecting many species in several Caribbean reefs have been reported
To improve our understanding of the spatial spread of this WS outbreak at the species level, we studied the temporal incidence variation along with the outbreak in two populations of the highly susceptible scleractinian coral Pseudodiploria strigosa (Precht et al, 2016; Álvarez-Filip et al, 2019; Landsberg et al, 2020) in northern Mexican Caribbean reefs
A remarkable finding of this study was the different dynamics in the WS outbreak in P. strigosa surveyed populations of the study sites, notwithstanding the two sites are relatively close to each other and in similar environmental settings

Summary

Introduction

In recent years outbreaks of a lethal white syndrome (WS) affecting many species in several Caribbean reefs have been reported. Patterns of a White Syndrome in P. strigosa (Precht et al, 2016). In recent publications, these outbreaks have been named “stony coral tissue loss disease” (SCTLD; FKNMS (Florida Keys National Marine Sanctuary), 2018), in our surveys signs correspond to the white plague type II (WP-II) description (Richardson et al, 1998). The spreading spatial patterns have suggested a primary infectious causal agent and diminishing tissue loss rates in affected colonies treated with antibiotics reinforce the idea that a bacterial infection is involved in SCTDL syndrome development (Neely et al, 2020). Landsberg et al (2020), ponder the possibility that there may be no infectious agent in the primary etiology of the SCTLD

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