Seamount - Mafia Island

The Gutter at Bass Point is a Sydney classic, and for good reason. We love it because it’s so reliable, even on days when other sites are blown out. The entry off the rocks is a splashy affair, sometimes a bit of a leap depending on the swell, straight into maybe four metres of water. Fin up quickly, then head north. You’ll hit a sizeable rock after a short swim, a kind of underwater landmark that signals the start of the fun. From there, the main channel, our favourite part, opens up, dropping to around 18 metres. It's a rocky bottom, a jumble of boulders and ledges, but the real show is the life tucked into every crevice. We’ve had some incredible encounters here: massive cuttlefish gliding by, sometimes a gang of bull sharks patrolling the deeper sections, and if you’re patient, the elusive Spitlure Frogfish camouflaged perfectly against the rock. It’s a site that rewards slow diving, peering under overhangs for nudibranchs, or scanning the sandy patches for an Oriental flying gurnard fanning its incredible fins. Visibility averages around nine metres, so it’s not always gin-clear, but it’s often good enough to really soak it all in. This is a site for the diver who loves exploring, who doesn't mind a bit of a current, and who gets a thrill from discovering critters.

Location: Mafia Island, Tanzania, Indian Ocean & East Africa
Coordinates: -10.227400, 40.188700
Type: pinnacle

Marine Protected Area: Mangrove

Best Time to Dive in Mafia Island

The warmest water temperatures in Mafia Island occur in January, averaging 28.8°C. The coolest conditions are in December at 28.8°C.

Monthly Water Temperatures

January: 28.8°C (air: 27.8°C)
February: 28.8°C (air: 28.0°C)
March: 28.8°C (air: 27.8°C)
April: 28.8°C (air: 27.0°C)
May: 28.8°C (air: 26.9°C)
June: 28.8°C (air: 26.0°C)
July: 28.8°C (air: 25.2°C)
August: 28.8°C (air: 25.0°C)
September: 28.8°C (air: 25.3°C)
October: 28.8°C (air: 26.1°C)
November: 28.8°C (air: 27.0°C)
December: 28.8°C (air: 27.7°C)

Nearest Dive Centres to Seamount

Marine Life in Mafia Island

Home to 165 recorded species including 94 hard corals, 63 reef fish, 3 sharks & rays, 2 jellyfish, 1 other, 1 whales & dolphins.

Notable Species

Green Turtle (Chelonia mydas)
Allison's Tuna (Thunnus albacares) - Reef Fish
Whale Shark (Rhincodon typus) - Sharks & Rays
Stripy (Katsuwonus pelamis) - Reef Fish
Bigeye tuna (Thunnus obesus) - Reef Fish
Bullet Mackerel (Auxis thazard) - Reef Fish
Tuna (Thunnus alalunga) - Reef Fish
Sperm Whale (Physeter macrocephalus) - Whales & Dolphins
Tail-spot Squirrelfish (Sargocentron caudimaculatum) - Reef Fish
Cauliflower coral (Pocillopora verrucosa) - Hard Corals
Smooth cauliflower coral (Stylophora pistillata) - Hard Corals
Stony coral (Porites cylindrica) - Hard Corals
Stony coral (Porites lutea) - Hard Corals
Larger star coral (Favites pentagona) - Hard Corals
Staghorn coral (Acropora aspera) - Hard Corals
Staghorn coral (Acropora listeri) - Hard Corals
Birdsnest coral (Seriatopora caliendrum) - Hard Corals
Thin birdsnest coral (Seriatopora hystrix) - Hard Corals
Staghorn coral (Acropora polystoma) - Hard Corals
Closed brain coral (Leptoria phrygia) - Hard Corals

Recommended Packing List for Seamount

Based on average water temperature of 28.8°C.

Shorty or Rashguard - warm 29°C water needs minimal exposure protection
Mask - essential for every dive
Fins
BCD - buoyancy compensator
Regulator - your most safety-critical piece of gear
Dive Computer - tracks depth, time, and NDL
Surface Marker Buoy (SMB) - essential for boat pickups
Dive Torch - useful for crevices and colour at depth
Underwater Camera - capture your diving memories