Thatch Cay
Dive site in the US Virgin Islands. Here's what has been recorded at this site month by month, how the region’s reefs have weathered ocean heat, and how to prepare.
Thatch Cay: dive site in the US Virgin Islands.
Entry
Shore and boat entries vary by site. We list only rules we can cite from official sources; entry points, depths and currents will be added once we can verify them.
- Buck Island Reef National Monument: scuba diving is allowed only at the two designated scuba moorings in the north lagoon, not on the underwater trail. Do not stand on or handle corals. NPS · Buck Island Reef NM
- Buck Island: private boats may anchor only in the anchorage area off West Beach. NPS · Buck Island Reef NM
Near this sitegeotagged about 1.1 km from the site coordinates Yellowtail snapper (Ocyurus chrysurus) · Bethany Harrison · CC BY 4.0 · iNaturalist
The surface noise falls away.
Reds go first. The world turns blue-green.
Then Thatch Cay rises to meet you.
What lives here, by month
Pick a month. These are the species most often recorded within about a kilometre in that month, from open survey records.
| Species | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mustard Hill Coral | ||||||||||||
| Lettuce Coral | ||||||||||||
| Massive Starlet Coral | ||||||||||||
| Great Star Coral | ||||||||||||
| Symmetrical brain coral | ||||||||||||
| Roughhead Triplefin | ||||||||||||
| Finger Coral | ||||||||||||
| Lowrelief Lettuce Coral | ||||||||||||
| Bumpy star coral | ||||||||||||
| Yellowtail Snapper | ||||||||||||
| Lesser Starlet Coral | ||||||||||||
| Boulder star coral |
Most-recorded species, all months
- Mustard Hill Coral (18)
- Lettuce Coral (14)
- Massive Starlet Coral (11)
- Great Star Coral (8)
- Symmetrical brain coral (7)
- Roughhead Triplefin (6)
- Lowrelief Lettuce Coral (5)
- Yellowtail Snapper (5)
- Finger Coral (5)
- Bumpy star coral (5)
- Lesser Starlet Coral (4)
- Lamarck's sheet coral (4)
- Boulder star coral (4)
- Spinyhead blenny (3)
- Horse-eye jack (3)
- Stoplight Parrotfish (3)
- Blushing Star Coral (3)
- Spotted cleaner shrimp (2)
- Sally Lightfoot crab (2)
- Boulder brain coral (2)
GBIF.org (2026-10-15), occurrence records within ~1 km, licensed CC0 or CC BY 4.0 only. Birds and land animals are excluded. Counts reflect survey effort, not abundance. 586 qualifying records. See them on GBIF. Common names: Wikidata (CC0) / GBIF. Species photos: Wikimedia Commons, credited with each species.
Forty-one summers of heat
Each stripe is one year since 1985, colored by its peak heat stress across NOAA's “Virgin Islands” region. These are NOAA Coral Reef Watch satellite figures for the whole region, not for this one site.
Heat stress, measured from orbit.
NOAA CRW virtual station “Virgin Islands”. NOAA's alert thresholds are 4 °C-weeks (Alert Level 1) and 8 °C-weeks (Alert Level 2). Station page · Method. Credit: NOAA Coral Reef Watch.
Conditions
Average sea temperature through the year. Check the live readings before you go.
Average sea surface temperature by month: NOAA CRW “Virgin Islands” station climatology (monthly means).
Buoy readings are measurements; forecasts are models. Use them for planning only, and assess conditions on site. Depth and visibility data aren't listed until we can cite a source.
Plan & prepare
- Read the official marine forecast the night before.Offshore, wind and sea state decide the day.
- Check the cited local rules above and pay any park fee before you dive.[Placeholder: verified operator list to come]
- Study this month's species above.You'll recognise more when you know the names.
- Hands off, fins up, buoyancy dialled. Log what you see.Your sightings can become tomorrow's open data.
Photographs from Thatch Cay
Openly licensed photos, each checked for location against its title, description, category or geotag. Labels show how close each one is to the site.
Credits
- Coordinates
- Wikidata Q7711334 (CC0) · position of the cay. Wikidata (CC0), mostly from US Geological Survey place names, plus one OpenStreetMap (ODbL) reef. Several use the named bay, cay or island, so treat them as approximate.
- Species records
- GBIF.org, CC0 & CC BY 4.0 records. By license: CC_BY_4_0: 569, CC0_1_0: 17
- Dataset
- EOD – eBird Observation Dataset · doi:10.15468/aomfnb (385 records) · GBIF
- Dataset
- NOAA National Coral Reef Monitoring Program Coral Demographic Data · doi:10.7289/v5vd6wts (81 records) · GBIF
- Dataset
- iNaturalist Research-grade Observations · doi:10.15468/ab3s5x (58 records) · GBIF
- Dataset
- NOAA National Coral Reef Monitoring Program Coral Benthic Assessment Data · doi:10.7289/v5vd6wts (25 records) · GBIF
- Dataset
- Birda - Global Observation Dataset · doi:10.15468/6kud7x (17 records) · GBIF
- Dataset
- International Barcode of Life project (iBOL) · doi:10.15468/inygc6 (8 records) · GBIF
- Dataset
- NMNH Extant Specimen Records (USNM, US) · doi:10.15468/hnhrg3 (6 records) · GBIF
- Dataset
- INSDC Sequences · doi:10.15468/sbmztx (3 records) · GBIF
- Query
- https://api.gbif.org/v1/occurrence/search?decimalLatitude=18.34912,18.369120000000002&decimalLongitude=-64.870974,-64.850974&license=CC0_1_0&license=CC_BY_4_0&taxonKey=44&taxonKey=206&taxonKey=229&taxonKey=136&taxonKey=225&occurrenceStatus=PRESENT&limit=0
- Heat stress & SST
- NOAA Coral Reef Watch, 5 km Regional Virtual Station “Virgin Islands”
- Hero photo
- At this sitegeotagged 1200 m from the site coordinates CokiBeachStThomasUSVI1 · Gruepig · CC BY-SA 3.0 · Wikimedia Commons
- Arrival photo
- Near this sitegeotagged about 1.1 km from the site coordinates Yellowtail snapper (Ocyurus chrysurus) · Bethany Harrison · CC BY 4.0 · iNaturalist
- Gallery
- 7 photos, credited under each image
- Species photos
- Wikimedia Commons, credited with each species. Full list: Data & sources