Tonga - Vava'u (TOVA40)

Setting

Lagoonal fringing reef. Reef sloped very gradually from 15-25 m then dropped more steeply.

General benthic features

Soft bottom community with a Porites framework. Massive Porites, 0.5-2 m by 1 m tall were the dominant corals, with cover ranging from 20-40%. In most cases other massive and branching corals had colonized exposed skeletal surfaces. Scattered through the reef were large table acroporids and erect thin branched spindly staghorn colonies, some 1-2 m wide and 1 m tall. Second most abundant coral was Lobata, with colonies up to 1 m diameter and many with partial mortality. A high diversity of other corals, including massive and branching Galaxea, several Favia, Goniastrea, Platygyra, Coscinaraea, Astreopora, Pachyseris rugosa, and Pachyseris plates, Merulina, Leptoseris, bottlebrush Acropora, P. damicornis, Seriatopora, Stylophora, and many other species were found.

Coral cover

• Reference: Khaled bin Sultan Living Oceans Foundation, Global Reef Expedition (in situ transect)
• Coral cover 21% (the expedition's in situ transects).
• Transect mean 21 ± 4.8% SE (n = 5 transects; Living Oceans Foundation per-transect benthic data); the headline above is this all-transect mean.

Stressors

About 40% of the massive Porites had some partial mortality, but little recent mortality. The 2013 survey notes for this site record two crown-of-thorns starfish, one of which had eaten a large table coral; no corallivorous snails were seen (Khaled bin Sultan Living Oceans Foundation expedition site notes, 2013; regional summary in Bruckner 2014). Anderson's sampling sheet records five of the eight Pocillopora colonies sampled here (colonies 69, 72, 73, 75, and 76) as 10-30% bleached, two of those (72 and 75) as possibly or likely unhealthy. There were also several large round sponges, branching sponges, and a very common gray encrusting sponge that was overgrowing corals and had thin upright branches. The sediment in places had patches of cyanobacteria. The Living Oceans Foundation transects here recorded 6.8% cyanobacteria and no recently dead coral.

Fish and other fauna

Three species of sea cucumbers were moderately common (pinkfish, spotted, and another Bohadschia).

Comparisons with other data

Coral Health Index 2.20/5 (Mayfield et al. 2021, Platax).

Dive record

TOVA40 (Vava'u): surveyed 24 Sep 2013 during the Khaled bin Sultan Living Oceans Foundation Global Reef Expedition.

Other notes

Anderson was busy sampling corals at this site, so the site description is derived from the Living Oceans Foundation survey team's site notes and benthic transect data. Those transects recorded 21% hard coral cover. Anderson sampled 8 Pocillopora colonies here (all labeled Pocillopora acuta), numbered 69 to 76 in the expedition series; the sampling sheet records five of them (colonies 69, 72, 73, 75, and 76) as 10-30% bleached, two of those as possibly or likely unhealthy. The photographs shown for this site are close-ups of the colonies Anderson sampled, so nothing here describes the reef's habitat, structure, or condition from imagery.