Philippines - Coron: Twin Lagoon (island-hopping snorkel)
Part of the regional summaries: Philippines - Palawan and Philippines
More info
Western Philippines (NOAA CRW virtual station)Twin Lagoon is a snorkel stop among the karst lagoons of Coron Island's south coast, where shallow coral, including bird's-nest and cauliflower-type branching corals, grows on the lagoon walls and floor. It was photographed only briefly on a 2017 island-hopping day.
Ang Twin Lagoon ay isang hinto para sa snorkel sa gitna ng mga karst na lagoon sa timog na baybayin ng Coron Island, kung saan tumutubo sa mga dingding at sahig ng lagoon ang mababaw na koral, kabilang ang mga sumasangang koral na uring bird's-nest at cauliflower. Sandali lamang itong nakunan ng larawan sa isang araw ng island hopping noong 2017.
Salin ng buod na ito gamit ang AI; ang Ingles ang opisyal na bersyon.
Three independent survey stations shown with the program’s logo — click one to see how far it is from this site.
One other CRD dive site with its own page within 5 km shown in orange — click a marker to open its page.
5 of the 6 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
Setting
Twin Lagoon, Coron Island, Palawan — a snorkel stop on the island-hopping day of 28 January 2017, in the karst lagoons on Coron's south coast.
General benthic features
Shallow coral grows on the lagoon walls and floor, with Seriatopora (Anderson's identification) among the frames (e.g., Image 1, Image 2, Image 4, Image 5, Image 7).
Coral cover
- Reference: Claude CV point count (this site's photos)
- Coral cover: 8.4% — a blind Claude computer-vision point count of 13 of Anderson's edited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table.
Stressors
No bleaching, disease, crown-of-thorns starfish, or other stressor is recorded for this snorkel stop (28 January 2017): Anderson's Palawan trip notes list Twin Lagoon only as a stop on the Coron island-hopping day, and the dive log has no entry for it. The blind computer-vision point count of 13 of Anderson's photographs from this stop scored no bleached coral.
Comparisons with other data
We found no other surveys at this site as of 2026. Within 5 km, three Reef Check stations recorded station-year means of 28–73% hard coral cover between 2004 and 2015; the nearest, Reef Check at CYC East Reef, 3.60 km away, read 34–73% between 2013 and 2015.
Other notes
Position is from the photographs' own GPS (8 frames), not an estimate.
CV model comparison
More info
A few colony-focused photos raise the mean; 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. Coralscapes v2 is shown as its own row for comparison only: the author does not consider Coralscapes reliable for these photos, so it is low confidence and never enters any average or summary. 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 | 14.6* | n = 13 · SE 2.0 |
| CoralSCOP edited | 19.1* | n = 13 · SE 5.8 |
| Claude (edited photos) | 8.4* | n = 13 · SE 3.8 |
| Coralscapes v2 (low confidence, never averaged) | 20.5* |
The two computer-vision methods agree within 4.5 pp (14.6–19.1%) and read 6.2–10.7 pp above Claude's blind point count (8.4%); the headline is Claude's blind point count because no transect or manual count exists here.
*Based on only 13 reef-habitat photos; this estimate is less certain.
See a more detailed, stand-alone version of this table.
Independent surveys nearby
Coral Reef DiagnosticsWithin 5 km, 3 independent survey stations recorded hard coral cover in 7 surveys between 2004 and 2015. Of the 2 stations surveyed in more than one year, 2 declined (by 38–39 points) between their first and latest surveys. Two stations share the longest span (2013–2015); one, CYC East Reef (Reef Check, 3.60 km away), went from 73% (best patch) in 2013 to 34% in 2015. The most recent nearby survey is from 2015, so these values predate recent heat stress. This site's own estimate (8.4%) is not compared with these surveys: none lies within 2 km.
Collected by other programs using different methods (Reef Check uses point-intercept transects), 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. Values above 70% are marked “best patch”: surveys often target the densest coral on a reef, so these may overstate the site as a whole.
| Agency | Site / location | Date | Hard coral cover (%) | Distance |
|---|---|---|---|---|
| Reef Check | Siete Pecados Islands | 2004 | 46% | 4.50 km |
| Reef Check | CYC East Reef | 2013–2015 | 34–73% (3 surveys) best patch | 3.60 km |
| Reef Check | CYC West Reef | 2013–2015 | 28–66% (3 surveys) | 3.97 km |
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.