Indonesia - Halmahera: Siko Tanjung
Part of the regional summaries: Indonesia - Halmahera and Indonesia - Maluku
More info
North Maluku, Indonesia (NOAA CRW virtual station)Siko Tanjung is an extensive branching Acropora reef flat worked in bad visibility and strong current, built partly on large tracts of old dead, coralline-overgrown staghorn framework that the living thicket now grows through. A handful of massive colonies are pale gray-white against normally pigmented neighbors and may be bleached or naturally pale. A blind Claude computer-vision point count puts coral cover around 41%.
Siko Tanjung adalah rataan terumbu Acropora bercabang yang luas, diselami dalam jarak pandang buruk dan arus kuat, sebagian dibangun di atas hamparan luas kerangka tanduk rusa tua yang mati dan ditumbuhi koralin, yang kini ditembus rumpun yang hidup. Beberapa koloni masif tampak putih-kelabu pucat di antara tetangganya yang berpigmen normal dan mungkin memutih atau memang pucat secara alami. Penghitungan titik buta oleh computer vision Claude menempatkan tutupan karang sekitar 41%.
Terjemahan ringkasan ini oleh AI; versi bahasa Inggris yang berlaku.
Two independent survey stations shown with the program’s logo.
These are unedited originals; edited versions will replace them.
This page shows 50 of the 143 photographs from this site, including every one the text cites.
28 of the 50 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
Setting
Siko Tanjung is a broad, gently domed reef top worked in the conditions Anderson's field note records: “bad visibility and fought strong currents for much of the dive.” The imagery carries that plainly — most wide frames are hazy and blue-flat, with the far side of each bommie already lost in suspended particles, and divers appear repeatedly hanging in current above the reef (e.g., Image 7, Image 20, Image 25, Image 33, Image 40, Image 46).
General benthic features
What the site actually holds is a very extensive branching Acropora reef flat: staghorn and bottlebrush thicket in dusty pink, lavender, and olive, running unbroken through dozens of frames (e.g., Image 2, Image 6, Image 34, Image 45, Image 49, Image 53).
Standing above it are big flat-topped tabulate Acropora plates, some over a meter across, digitate and corymbose colonies, foliose plates, brown Lobophytum, and Sinularia leathers, and a scatter of massive Porites and one textbook meandroid brain coral (e.g., Image 1, Image 3, Image 9, Image 11, Image 21, Image 26, Image 38, Image 42, Image 43).
Coral cover
- Reference: Claude CV point count (this site's photos)
- Coral cover: 41% — a blind Claude computer-vision point count of 143 of Anderson's unedited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table.
Stressors
Two things stand out beyond the composition. First, large tracts of the flat are dead standing and broken staghorn framework, old dead skeleton overgrown by pink and magenta coralline algae and green turf (clearest in four frames), interleaved with the living thicket (e.g., Image 4, Image 13, Image 44, Image 52) — an old mortality event that the reef is still built on.
Second, a handful of massive colonies are pale gray-white, clearly paler than their normally pigmented neighbors, one of them photographed three times; they may be bleached or naturally pale, and the photographs cannot settle which (e.g., Image 8, Image 19, Image 37).
Fish and other fauna
A cushion star was seen on the rubble beside two small snow-white branching colonies.
Comparisons with other data
In 2024, WCS Indonesia surveyed two stations, Inti Siko and Inti Gafi, for its Guraici MPA project (data via MERMAID), recording 25–50% hard coral cover. This pin's position is approximate (an island-level placement on the Inti Siko station, not a dive-site fix), so no station is compared with this site by distance or treated as this site; station names are not dive-site names.
CV model comparison
More info
A few low-cover photos (sand, rubble, or open bottom) pull the mean down; the median is the typical photo. No computer-vision method yet estimates coral cover accurately on new images, so treat this as indicative rather than a measurement; it is revised as the methods improve.More info
DINOv3 and CoralSCOP were run on the same photos and are listed for comparison. No diver transect exists for this trip, so agreement between the rows is not accuracy, and no computer-vision method yet estimates coral cover accurately on new images; treat every row as indicative.| Method | Hard coral cover (%) | Photos (n) ± SE |
|---|---|---|
| In-house DINOv3 | 30.5 | n = 143 · SE 0.9 |
| CoralSCOP unedited | 32.3 | n = 143 · SE 1.7 |
| Claude | 41.3 | n = 143 · SE 1.7 |
The two computer-vision methods agree within 1.8 pp (30.5–32.3%) and read 9.0–10.8 pp below Claude's blind point count (41.3%); the headline is Claude's blind point count because no transect or manual count exists here.
See a more detailed, stand-alone version of this table.
Independent surveys nearby
The survey table lists 2 independent survey stations, which recorded hard coral cover in 2024. Since 2021, station-year means average 37% (range 25–50%; n = 2 station-years from 2 surveys).
Collected by other programs using different methods (MERMAID is a data platform: each MERMAID row names the organization that did the survey, and its method is in the row's hover text), so these are context for the figures above, not a like-for-like comparison. Where a station was surveyed more than once, the cell shows either the range of its values or, as a single value, the mean of surveys made in one year. Station names are not dive-site names.
| Agency | Site / location | Date | Hard coral cover (%) | Distance | Link |
|---|---|---|---|---|---|
| WCS Indonesia via MERMAID | Inti Siko | 2024 | 25% | — | Adiyoga D, Cholic O, Gunawan I, Rayhan A, Sutanto S, Syah L, Zulfikri M. 2024. Guraici MPA 2024. MERMAID |
| WCS Indonesia via MERMAID | Inti Gafi | 2024 | 50% | — | Adiyoga D, Cholic O, Gunawan I, Rayhan A, Sutanto S, Syah L, Zulfikri M. 2024. Guraici MPA 2024. MERMAID |
Data & links
All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics and the organizations named in the data sources above.
© Coral Reef Diagnostics.