Acropora aculeus

Acropora aculeus is a stony coral in the family Acroporidae, recognized by its arborescent to bottlecap-shaped colonies formed from finely branching structures typical of the genus. Like other Acropora species, it is a colonial cnidarian composed of thousands of tiny polyps that secrete calcium carbonate skeletons, building the physical framework of reef ecosystems. It relies on symbiotic zooxanthellae algae for the majority of its energy through photosynthesis, while polyps also capture plankton from the water column.

As a reef-building species, it contributes structural complexity that supports fish and invertebrate communities.

The species inhabits shallow marine neritic waters across the Indo-Pacific, with recorded presence in Australia, China, and Japan, typically on reef slopes and flats where light penetration supports its symbiotic algae.

Acropora aculeus faces a broad array of pressures. Fishing and harvesting activities, along with recreational use, physically damage colonies, while agricultural and urban runoff introduce nutrients and sediments that degrade water quality and favor disease and algal overgrowth. Invasive species and native predators such as crown-of-thorns starfish add further biological stress.

Habitat alteration, storm damage, and flooding—intensified by broader environmental change—compound structural loss, and fire-related runoff and land-use changes in coastal catchments add indirect pressure through altered water chemistry.

Conservation measures include the species' listing under CITES Appendix II, inclusion in marine protected areas across parts of its range, and reef monitoring programs conducted by regional governments and research institutions. Water quality regulations targeting agricultural runoff in some jurisdictions offer partial mitigation.

The population trend is decreasing, and the species is classified as Endangered. Given the persistence and diversity of ongoing threats, its long-term outlook remains precarious without sustained reef management and water quality improvements.