Fanga'uta Lagoon

Fanga'uta Lagoon is a large semi-enclosed tidal lagoon on Tongatapu, Tonga, covering 28.35 km². Together with the neighbouring Fanga Kakau it forms a double lagoon system around which the island wraps^[1]. It was declared a natural reserve in 1974^[2].

The lagoon is a nursery area for both fin and shellfish and supports fisheries inside the lagoon and in the nearby sea^[1]. It is also a key breeding area for birds and fish^[2].

The lagoon's habitats are sheltered waters, mangroves, seagrass beds and patch reefs^[1]. Mangroves grow along its shores^[2]. Its catchment includes Taloa, the last remaining rainforest in the area^[1].

Tongatapu is an uplifted coral reef, about 40 km long and 257 km² in area, and is formed from coral limestone^[1][2].

Nuku'alofa has a tropical rainforest climate with a mean daily maximum of 27.3 °C, a minimum of 20.9 °C and about 1,721 mm of rain a year^[2].

More than 40,000 people live in the lagoon's catchment, and the area holds archaeological sites reflecting Tonga's roughly 3,000-year settlement history^[1].

The lagoon was declared a marine reserve in 1974. A 2001 government management plan was never implemented, and the Tonga Ridge-to-Reef project, begun in 2014, produced the Fanga'uta Stewardship Plan, gazetted under the Environment Act^[1].

The lagoon is valued for its fisheries, mangroves and cultural sites, with marine eco-tourism among the planned actions^[1].

The lagoon lies on the doorstep of Nuku'alofa, about 5 km from the town. The sources describe no visitor facilities.

Threats include changed tidal flows, heavier fishing, habitat loss from urban and farming practices, and land-based pollution. The stewardship plan sets protection, sustainable use and rehabilitation zones, and four catchment communities have committed to Special Marine Protected Areas inside the reserve^[1].