Tonga - Vava'u (TOVA52)

Setting

The 2013 survey notes name this site Coral Pinnacles off Ofu Reef South, a submerged seamount in the Vava'u group.

General benthic features

Table Acropora is the recurring element — single large plates standing clear of dark undercut bases, pairs of overlapping tables, and smaller plates scattered across the slope behind them — set among corymbose and digitate Acropora, branching staghorn clumps, knobby pocilloporid colonies in mauve and pink, encrusting and foliose sheets, and meandering massive heads. Coral form and color vary noticeably from frame to frame across the site: some views are close-packed with almost no visible substratum between colonies, while others show colonies well spaced over pale hardground and rubble, so the slope is patchy rather than uniform. One small patch reads as a community portrait: a fine-branched colony Anderson identified as Seriatopora hystrix growing beside a mustard-yellow branching colony, a brown encrusting plate coral, and a solitary mushroom coral, all over red-maroon coralline crusts.

Coral cover

• Reference: Khaled bin Sultan Living Oceans Foundation, Global Reef Expedition (in situ transect)
• 47%, from the Khaled bin Sultan Living Oceans Foundation's in situ transect survey (Global Reef Expedition site data); the photographs illustrate the site. Algal cover is 45% of the benthos.
• Transect mean 47 ± 11% SE (n = 5 transects; Living Oceans Foundation per-transect benthic data); the headline above is this all-transect mean.

Stressors

The cushion stars (Culcita) in Image 5, Image 6, Image 7, and Image 8 are coral predators, and they are the site's most concrete condition observation from the imagery; the frames cannot establish how many were present overall.

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Beyond that, the photographs cannot settle the site's condition: the wide frames are ambient-light shots with blue-green casts at ~29 m, no bleaching, lesion or predation scar resolves reliably at these ranges, and pale-looking tissue in them is a light artifact rather than evidence. Anderson's sampling sheet for this dive does record bleaching in the colonies sampled at 10-17 m: two of the six 50% bleached and possibly unhealthy, and three more about 20% bleached. The Living Oceans Foundation transects here recorded 0.5% cyanobacteria and no recently dead coral.

Fish and other fauna

Fish are conspicuous here: a dense school of dark damselfish and chromis hangs in the water column above the reef, with a small yellow-bodied fish among them, and planktivores work over the slope. Four frames form a separate set of animals Anderson identified as pincushion stars: close views of cushion stars (Culcita) resting on pale reef rock, rubble, and sand — a dark maroon individual, a mottled cream-and-brown individual on coralline-crusted pavement, another mottled individual among rubble, and a small olive one out on open sand among green algal tufts (e.g., Image 5, Image 6, Image 7, Image 8). At least three and probably four separate animals are recorded.

Comparisons with other data

James Cook University and the Ministry of Fisheries Tonga surveyed a nearby station (Taunga Outer Reef 1), 0.47 km from the pin; we could not confirm that it is the same reef. If you have survey data from this site to share, please email us.

Other notes

Photo review of 21 habitat frames plus 33 sampled-colony close-ups (Vava'u, 28 Sep 2013). The account on this page is written from the habitat frames only; the colony images are treated purely as a record of what was sampled. Sixteen of the twenty-one are wide or oblique views of the reef slope at or near survey depth, and they agree with one another: a gently to moderately inclined bottom carrying a structurally three-dimensional, tabular-dominated community. Several frames carry a survey tape or line running across the bottom, and one has a tape laid directly over a large table — these are frames shot on the transect itself, which is a useful reminder that the quantitative record for this site comes from that tape and not from the pictures. Six Pocillopora colonies were sampled here (colonies 106-111), four of them identified as P. acuta in Anderson's own field records; two (colonies 107 and 108) were not genotyped (107 was never extracted, and DNA extraction failed for 108); the sample sheet identifies 107 as P. damicornis and leaves 108 unidentified. The 33 close-ups are repeat polyp-scale macro, tag, and setting shots of only those six colonies — numbered tags appear in frame, most held by a gloved hand — and describe the colonies, not the reef.