クロマツミドリイシ

Overview

Acropora grandis is a large, colonial stony coral known for its impressive, bush-like branching structure. Native to the tropical western Indo-Pacific, this species is commonly found in a variety of reef environments, including lagoons and upper reef slopes.

Distribution & habitat

This species is widespread throughout the tropical western Indo-Pacific, with a range extending from East Africa to the east coast of Australia. It thrives in diverse environments, particularly in protected lagoons and on upper reef slopes, typically at depths ranging from 5 to 25 meters.

Appearance

Colonies are arborescent and can grow into massive, tangled clumps reaching up to 7 meters across. Its growth form is highly influenced by its environment: in shallow, high-energy waters, it tends to form compact, prostrate bushes with thick branches, while in deeper, calmer waters, the structure becomes more open and upright. The branches are characterized by fragile tips that are easily damaged. The radial corallites vary in size and shape, with those near the branch tips appearing elongated and tubular. While typically a rich reddish-brown, colonies can also display shades of blue, green, or purple, usually with noticeably paler branch tips.

Biology & behavior

As a colonial coral, it provides essential structural complexity that serves as a vital habitat for various reef-dwelling organisms, including fish, crustaceans, and mollusks. The polyps generally possess twelve tentacles, one of which is elongated, and are linked by a network of internal channels. Like many reef-building corals, it relies on a symbiotic relationship with zooxanthellae for energy, making it sensitive to environmental stressors such as pollution and rising water temperatures, which can lead to bleaching.