A dive briefing · Cayman Brac & Little Cayman, Cayman Islands

Radar Reef

Dive site at a Cayman Islands Department of Environment public mooring. 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.

Cayman Brac & Little Caymanreef

At this sitegeotagged 774 m from the site coordinates Barred hamlet (Hypoplectrus puella) · marique · CC BY 4.0 · iNaturalist

Yellow tube sponge (Aplysina fistularis)

Chapter I · Arrival

Radar Reef: dive site at a Cayman Islands Department of Environment public mooring.

19.7159° N79.8339° W · Cayman Islands DoE public mooring “Radar Reef”

425open records · GBIF

11species recorded

At this sitegeotagged 774 m from the site coordinates Yellow tube sponge (Aplysina fistularis) · marique · CC BY 4.0 · iNaturalist

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.

Mooring position (cited)Coordinates are the published position of the named mooring: Cayman Islands DoE public mooring “Radar Reef” (Cayman Brac, January 2023).

To verifyDepth range, entry points and current notes. We publish them only with a citation.

Local rules (cited)

The DoE has installed public moorings to protect reefs from anchor damage. Use a mooring instead of anchoring whenever possible; it is an offence to damage coral anywhere in Cayman waters. Cayman Islands DoE · Public Moorings
The maximum stay on a public mooring is 3 hours. Do not use moorings in winds of 25 knots or more. Cayman Islands DoE · Public Moorings
Marine Park zones carry their own rules (for example, no taking of marine life in Marine Reserve zones and no SCUBA diving in No Diving zones without permission). Check the zone with the DoE app or brochures. Cayman Islands DoE · Marine Parks
Wildlife Interaction Zones are the only places in the Cayman Islands where you may legally feed or interact with marine life. Cayman Islands DoE · Marine Manners

At this sitegeotagged 774 m from the site coordinates Yellow tube sponge (Aplysina fistularis) · marique · CC BY 4.0 · iNaturalist

**Open media** · At this sitegeotagged 774 m from the site coordinates Barred hamlet (Hypoplectrus puella) · marique · CC BY 4.0 · iNaturalist

The surface noise falls away.

Reds go first. The world turns blue-green.

Then Radar Reef rises to meet you.

Barred hamlet (Hypoplectrus puella)

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.

Oct

October · 23 qualifying records

Life calendar · records per month for this site's most-recorded species (blank means not in that month's top list)

Species	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Finger Coral
Boulder star coral
Mustard Hill Coral
Boulder star coral
Ten-ray Star Coral
Massive Starlet Coral
Smooth Flower Coral
Great Star Coral
Rose Coral
Grooved brain coral
Staghorn coral

Most-recorded species, all months

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. 425 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 “Cayman Islands” region. These are NOAA Coral Reef Watch satellite figures for the whole region, not for this one site.

19852026

Reef health report · Cayman Islands

Heat stress, measured from orbit.

Degree Heating Weeks · 2026-10-1311.9°C-weeks · NOAA status: Bleaching Watch

NOAA CRW virtual station “Cayman 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.

Peak per year · dashed lines at 4, 8 and 16 °C-weeks

The past twelve months

Conditions

Average sea temperature through the year. Check the live readings before you go.

Average sea surface temperature by month: NOAA CRW “Cayman Islands” station climatology (monthly means).

Cayman Islands National Weather Service · forecast →NDBC 42057 · Western Caribbean (~361 km, open ocean) →

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.

VII

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 Radar Reef

Openly licensed photos, each checked for location against its title, description, category or geotag. Labels show how close each one is to the site.

**Threespot damselfish (Stegastes planifrons)**At this sitegeotagged 774 m from the site coordinates marique · CC BY 4.0 · iNaturalist

**Pederson cleaner shrimp (Ancylomenes pedersoni)**At this sitegeotagged 774 m from the site coordinates marique · CC BY 4.0 · iNaturalist

**Saddled blenny (Malacoctenus triangulatus)**At this sitegeotagged 774 m from the site coordinates marique · CC BY 4.0 · iNaturalist

**Finger coral (Porites porites)**At this sitegeotagged 774 m from the site coordinates marique · CC BY 4.0 · iNaturalist

**Lettuce coral (Agaricia agaricites)**At this sitegeotagged 774 m from the site coordinates marique · CC BY 4.0 · iNaturalist

**Symmetrical brain coral (Pseudodiploria strigosa)**At this sitegeotagged 774 m from the site coordinates marique · CC BY 4.0 · iNaturalist

**French angelfish (Pomacanthus paru)**At this sitegeotagged 774 m from the site coordinates marique · CC BY 4.0 · iNaturalist

Credits

Coordinates: Cayman Islands DoE public mooring “Radar Reef” (Cayman Brac, January 2023) · source · Cayman Islands Government, public data. Cayman Islands Department of Environment, Little Cayman and Cayman Brac public moorings (GPX, January 2023). Each site uses its named mooring; the Bloody Bay Wall sites are moorings along that wall.
Species records: GBIF.org, CC0 & CC BY 4.0 records. By license: CC_BY_4_0: 413, CC0_1_0: 12
Dataset: EOD – eBird Observation Dataset · doi:10.15468/aomfnb (249 records) · GBIF
Dataset: Atlantic and Gulf Rapid Reef Assessment - Benthic · doi:10.15468/vmcydh (164 records) · GBIF
Dataset: NMNH Extant Specimen Records (USNM, US) · doi:10.15468/hnhrg3 (8 records) · GBIF
Dataset: CAS Herpetology (HERP) · doi:10.15468/bvoyqy (4 records) · GBIF
Query: https://api.gbif.org/v1/occurrence/search?decimalLatitude=19.7059,19.725900000000003&decimalLongitude=-79.843933,-79.823933&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 “Cayman Islands”
Hero photo: At this sitegeotagged 774 m from the site coordinates Barred hamlet (Hypoplectrus puella) · marique · CC BY 4.0 · iNaturalist
Arrival photo: At this sitegeotagged 774 m from the site coordinates Yellow tube sponge (Aplysina fistularis) · marique · CC BY 4.0 · iNaturalist
Gallery: 7 photos, credited under each image
Species photos: Wikimedia Commons, credited with each species. Full list: Data & sources