In August 2022, Tonga’s reefs were surveyed for the first time following the devastating eruption of the Hunga Tonga-Hunga Haʻapai volcano and resulting tsunami. Despite the scale of the event, the survey—led by the Government of Tonga in partnership with the Waitt Institute and Scripps Institution of Oceanography—found that reef impacts were highly localised, with several areas showing encouraging resilience.

Key findings include:

• Coral cover decreased in Ha’apai and parts of Tongatapu, particularly at sites exposed to the tsunami. However, reefs in Vava’u and sheltered areas showed coral growth and structural integrity.

• Coral recruitment was generally low, though select sites, like ‘Eueiki, recorded high juvenile densities.

• Reef fish communities remained stable across all regions, with Vava’u showing the highest biomass, including a presence of large herbivores and predatory species.

• Macroinvertebrate diversity declined significantly—from 56 species in 2017 to 27 in 2022—particularly affecting sea cucumber populations.

Importantly, this assessment strengthens the foundation for Tonga’s Special Management Areas (SMAs) and marine spatial planning goals. With over 50 SMAs established, the report provides essential insight to guide post-disaster reef recovery, local fisheries sustainability, and community-based marine protection.