Short-term in situ shading effectively mitigates linear progression of coral-killing sponge Terpios hoshinota.

Thangadurai Thinesh,Ramasamy Pasiyappazham,George Seghal Kiran,Muthamizh Selvan,Joseph Selvin,Ramu Meenatchi,Polpass Arul Jose

doi:10.1371/journal.pone.0182365

Thangadurai Thinesh, Ramasamy Pasiyappazham + Show 5 more

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https://doi.org/10.1371/journal.pone.0182365

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Journal: PloS one	Publication Date: Aug 7, 2017
Citations: 19	License type: CC BY 4.0

Affiliation: Pondicherry University, Madurai Kamaraj University

Abstract

The coral-killing sponge, Terpios hoshinota is a global invasive species that has conquered coral patches within a short span of time, which has led to a significant decline in living coral cover at various geographical locations. In this study, we surveyed the linear progression and impact of the Terpios invasion on live coral patches along Palk Bay, Indian Ocean, from August 2013 to August 2015. The field inventory revealed an extensive fatality rate of 76% as a result of Terpios outbreak. Experimental findings showed that symbiotic cyanobacteria act as a nutritional factory for the aggressive growth of Terpios. Shading hypothetically impairs the nutritional symbiont of the invasive species: the effect of sunlight on cyanobacterial biomass and its influence on Terpios progression over live coral patches was tested through in situ shading experiments. This study showed that artificial shading with cotton fabric could effectively mitigate sponge growth on live coral without affecting coral homeostasis.

Highlights

The encrusting coral-killing sponge Terpios hoshinota outbreak causes significant declines in living coral cover in tropical coral reefs
The encrusting sponge from Palk Bay reef in India was named as Terpios sp
Outbreak of coral killing sponge, Terpios hoshinota is frequently expanding its geographical range and is emerging as a threat to one of the most important coral reef ecosystems worldwide (30 to 80% mortality in coral reefs of various geographical locations) [1,2,3,4,5,6,7,8,9,10]. This is the first study to report evidence of rapid coral mortality in Palk Bay caused by Terpios invasion

Summary

Introduction

The encrusting coral-killing sponge Terpios hoshinota outbreak causes significant declines in living coral cover in tropical coral reefs. After the first report on Terpios by Bryan in 1973 [1], the invasion has been theorized to be expanding its geographical range [2] and has caused mortality in many coral genera [3,4]. Terpios hoshinota is a very thin encrusting sponge (aggressive space competitor) actively overgrowing on stony corals [1, 11,12].

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