Philippines - Anilao: Dive and Trek

Setting

The second dive of 30 September 2016, at the Dive and Trek private marine sanctuary at Bauan, reached by bangka outrigger beneath a steep forested headland; all 89 available frames were reviewed, five of them topside boat and shoreline shots. It is a managed reserve and the photographs make that obvious.

General benthic features

A standing Virgin Mary figure, thickly encrusted with coralline algae and sponge, and a large submerged cross with fish shoaling around it both sit on the slope (e.g., Image 7).

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Hard coral cover is markedly higher here than at Ligpo, on a gentle to moderate slope of near-continuous framework: branching and corymbose Acropora, tabular plates, foliose lettuce corals compatible with Echinopora lamellosa and Merulina, plating Montipora, massive, and columnar Porites and Goniopora, brain corals, a Pachyseris-type mound, Seriatopora and Stylophora thickets, and bubble corals including a striking turquoise colony (e.g., Image 3, Image 5, Image 8, Image 9, Image 10, Image 13, Image 18, Image 20, Image 21, Image 22, Image 23, Image 24, Image 25).

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Coral cover

Cover comes from two computer vision methods, neither preferred. DINOv3 point classification gives 27.3% hard coral (95% CI 24.2-30.4) from all 89 frames and 1,780 points. CoralSCOP computer vision, its full run now finished, gives 31.1% across all 89 frames (median=31.8%, bootstrap 95% CI 27.2-34.9), against the 29.7% from the 20-frame subset the map's 28.5% was built on. The published spread is 2.4 points and the completed run widens it only to 3.7; the two site means agree, but they agree for weak reasons - across the frames the two models correlate at only r = 0.49, and CoralSCOP's single highest frame, at 84.0%, is a giant-clam portrait, while the bleached-white Acropora stand is scored 59.1% because computer vision segments coral shape regardless of condition. The two models fail differently. CoralSCOP computer vision reads high on low-cover reefs - a median=1.68x a co-located Reef Check diver survey, 4.6x at worst. DINOv3 is strong in-domain (6-class macro-F1 0.62, hard coral recall 0.82) but collapses off-domain: cross-domain point accuracy 0.17-0.25, ceiling near 35-50%; on the five topside frames in this set it still returned 13-27% hard coral for photographs containing no benthos at all. Neither is a diver survey or a transect; both are provisional and a better model will supersede them. Coral cover: 29% — photo-derived, and the two methods broadly agree (27% vs 31%). Two independent computer vision passes over all 89 of Anderson's frames from this dive give a DINOv3 calibrated point classifier reading of 27.3% (95% CI 24–30%, block bootstrap) and a CoralSCOP computer vision of 31.0%, a spread of 3.7 percentage points. The map publishes their mean so sites can be ranked against one another, but the 27–31% range is the honest statement of what is known here: the two products have different denominators and should not be collapsed into one measurement. This number comes from CoralSCOP and DINOv3, which Anderson considers a stopgap; he is evaluating other models and will regenerate the figure once a better one is identified.

Stressors

The reef reads healthy - high cover, little algal overgrowth - with one clear exception: a stand of stark-white branching Acropora, architecture still intact, indicating recent bleaching or very recent mortality.

Fish and other fauna

A giant clam garden is the site's strongest signal: numerous Tridacna across several size classes and species, mantles in iridescent blue, violet, green, and mottled brown, consistent with a restocking and protection program (e.g., Image 11, Image 14, Image 15, Image 19).

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Habituated fish swarm divers - sergeant majors, butterflyfishes, surgeonfishes, and unicornfishes, moorish idols, redtooth triggerfish, and wrasses (e.g., Image 6).

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Anderson photographed two large dorid nudibranchs here, a cream animal boldly marked with black arches that he recorded as never before seen, and a black Nembrotha-type with crimson gills and a violet foot margin.

Comparisons with other data

No independent survey was made at this exact site; the nearest ones are listed in the table below.