blister coral
VU

blister coral

Horastrea indica

Unknown

Photo: iNaturalist: (c) Annette Gerber, some rights reserved (CC BY-NC), uploaded by Annette Gerber

Overview

Horastrea is a monotypic genus of stony coral in the family Coscinaraeidae. It is represented by the single species Horastrea indica, the blister coral. It is native to the southwestern Indian Ocean where it is found in shallow water sandy reefs. It was first described by M Pichon in 1971.

Horastrea indica faces significant threats from ocean warming and acidification, which cause coral bleaching and reduce calcification rates essential for skeletal growth. Coastal development, pollution, and destructive fishing practices further degrade the shallow reef environments where this species occurs, while sedimentation from terrestrial runoff smothers coral polyps and reduces water quality.

Threat summary

Habitat

Shallow tropical coral reefs and reef flats in the Indo-Pacific region, typically occurring in clear, warm waters at depths of 1-20 meters. This species forms small colonies on hard substrates in areas with moderate to strong water movement.

MARINE· major

Threatened in French Southern Territories

Calidris ferrugineaVU

Calidris ferruginea

Declining
EN

Montipora stilosa

Declining
VU

tipped bubblegum coral

Physogyra lichtensteini

Unknown
VU

starry cup coral

Acanthastrea hemprichii

Unknown

Frequently asked questions

Why is blister coral classified as Vulnerable?
blister coral is classified as Vulnerable because the population is declining and the species faces a high risk of extinction in the medium-term future if current pressures continue. Horastrea indica faces significant threats from ocean warming and acidification, which cause coral bleaching and reduce calcification rates essential for skeletal growth. Coastal development, pollution, and destructive fishing practices further degrade the shallow reef environments where this species occurs, while sedimentation from terrestrial runoff smothers coral polyps and reduces water quality.
Where does blister coral live?
blister coral occurs in French Southern Territories, Kenya, Madagascar, Mauritius, Mayotte, and Mozambique (plus 2 other countries). Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to blister coral?
The main threats to blister coral are ai-1, ai-2, ai-3, and ai-4. The full IUCN-classified threat record for this species is detailed on the species page.

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