Acropora millepora

Acropora millepora is a fast-growing stony coral known for its branching, staghorn-like colonies and corymbose growth form, which can vary widely depending on local wave exposure. Colonies are formed by colonial polyps that secrete calcium carbonate skeletons, building the structural framework of reef ecosystems. Like other reef-building corals, it hosts symbiotic photosynthetic algae (zooxanthellae) that supply much of its energy, and it reproduces via mass spawning events synchronized to lunar and seasonal cues.

As a foundational reef-builder, it provides habitat complexity supporting fish and invertebrate communities.

The species occurs across the Indo-Pacific region, with records from Australia, Vietnam, China, Japan, India, Yemen, and South Africa. It inhabits marine neritic and intertidal zones, typically on shallow reef flats and slopes, and is sometimes associated with fringing mangrove-adjacent reef systems.

Populations are declining due to a combination of pressures. Coastal mining and quarrying degrade adjacent habitats and increase sedimentation, while fishing and harvesting activities and recreational use (including diving and anchoring) cause direct physical damage. Nutrient and pollutant loading from agricultural runoff and untreated domestic wastewater promotes algal overgrowth and reduces water quality.

The species is also vulnerable to disease outbreaks, predation by native species such as crown-of-thorns starfish, and habitat shifts linked to broader environmental change.

Conservation responses include marine protected area designations, reef restoration and coral propagation programs, water quality regulation, and international trade monitoring under CITES. Research into thermal tolerance and selective breeding is ongoing in several range states.

Given continuing habitat degradation and cumulative stressors, the population trend remains decreasing, and the species is currently assessed as Endangered.