Why does the western tropical Pacific have especially diverse coral reefs?

The western tropical Pacific is home to the world's most diverse and extensive coral reefs, a region largely encompassed by the Coral Triangle. This exceptional biodiversity is driven by several key factors:

• Evolutionary History: The region's warm monsoonal climate and complex, variegated landforms have historically promoted the evolution of unique Indo-Pacific marine species.1
• Geographic Connectivity: Tropical sea passages between the Pacific and Indian oceans have facilitated the exchange and diversification of marine life, contributing to a rich reef fauna.1
• Environmental Conditions: Coral reefs thrive in tropical surface waters where mean annual temperatures remain between approximately 23–25 °C (73–77 °F). The western Pacific provides these stable, warm conditions necessary for the growth of reef-building corals.21

The Coral Triangle alone contains roughly three-quarters of the world's coral species and more than one-third of all global coral reef fish species, highlighting the region's status as a global center of marine biodiversity.3