Sangeang & Bima Bay · Indonesia · Muck & macro
Hot Rocks
Fumaroles stream volcanic gas bubbles straight up out of the black sand
Area photo: Bernard Picton · CC BY-SA 4.0
Hot Rocks is a shallow slope of black volcanic sand on the southern face of Sangeang, where active fumaroles push continuous streams of gas bubbles up through the seabed. Divers come for the vents themselves and for the critters living around them, with mimic octopus and ghost pipefish among the residents.
Where it is and how deep
8.1959° S, 119.0698° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
The dive works the vent field, where several fumaroles sit between 8 and 15 m on the black-sand slope and release steady columns of bubbles. The sand and rubble around them hold resident mimic octopus and ghost pipefish, and mandarin fish come out at dusk. The slope carries no significant current, so the dive is spent hovering slowly over the vents and the critters beside them.
Marine life and season
- Octopus & cuttlefish
- Mandarinfish
- Macro critters
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fair | Fair | Fair | Good | Good | Prime | Prime | Prime | Prime | Prime | Good | Fair |
Season follows Sangeang & Bima Bay: April to November is the season and June to October the peak; in January and February most liveaboard operators do not run.
Dive videos
Hot Rocks Sangeang Volcano · All4DivingIndonesia on YouTube
Sources
- Best Dive Sites in Sumbawa — Neptune Liveaboards
More dive sites in Sangeang & Bima Bay
Sunset and night muck dive on the volcano's western black sand
Eagle rays and whitetip sharks cruising the edge of the drop-off
Reef
A lone coral bommie on the sand flat east of the volcano, ringed by bigeye trevally
Similar dives elsewhere
Mandarin fish and ghost pipefish on a sheltered Rinca muck slope
Muck slope and coral bommies ten metres apart
Debris slope from 3 to 18 m, dived for frogfish and nudibranchs
Coleman shrimp on fire urchins, and the coast's smallest finds