The Turtles of Sipadan
A guest asked me on Tuesday if we might get lucky and spot a turtle at Sipadan. I told him dodging them is half the work and he thought I was joking. Two hours later we dropped into the shallows at Coral Gardens and he spent his safety stop physically reversing away from a green turtle that had claimed his patch of water. Sipadan does not have a turtle population. Sipadan is a turtle metropolis. You arrive for the swirling barracuda vortex at the northern point but you spend the rest of the week navigating around the thickest concentration of turtles in the Celebes Sea. The density turns the reef into a crowded transit hub.
Table of Contents
- How to tell the cast apart
- The grazer and the lock picker
- Turtle Patch: the sunlit parking lot
- The Drop-Off: the vertical highway
- Turtle Cavern: the blue cathedral
- The threats you do not see
- The permit pool
How to tell the cast apart
You do not need a biology degree to identify the animals on the wall. They wear their identities right on their faces. If you drift above a resting animal, check the scales directly between its eyes. A green turtle wears a single pair. A hawksbill wears two pairs stacked together. The jaw lines tell the rest of the story. The hawksbill carries a pronounced sharp overbite that looks like a raptor beak. The green turtle has a blunt and rounded snout equipped with a serrated lower jaw.
The armour is the next giveaway. The central plates on a hawksbill overlap heavily to form a layered shield with a jagged trailing edge. The green turtle wears a shell of flat plates that create a smooth rim. They also differ wildly in bulk. Nesting green turtles measured at Pom Pom island average 101.7 centimetres down the shell. The hawksbills measured at Pom Pom come in much smaller at an average of 80.6 centimetres.
The most persistent myth on the boats is that the green turtle gets its name from a brown or olive shell. The truth is stranger. The name comes from the colour of their body fat. A life spent eating algae infuses their internal tissues with heavy concentrations of chlorophyll and turns their fat the colour of an avocado. You are what you eat.
The grazer and the lock picker
Their jaw mechanics exist for a reason. The adult green turtle is a strict vegetarian. They mow the seagrass beds and the algae pastures flat. That diet dictates their schedule and their address on the reef. I often find them hovering over the shallow sunlit plateaus where the plant life grows. A green turtle in the shallows moves with the slow deliberation of a blimp.
The hawksbill operates a different shift. They are specialist sponge eaters. Their food lives wedged tight in the cracks of the deep drop-offs. A hawksbill uses that sharp beak to pry toxic sponges out of the limestone. Because they hunt in the cracks, I often see them on the vertical walls at Hanging Gardens. I have often watched them work a wall crevice like a safecracker.
Sabah Parks enforces a blanket no-touch and no-gloves rule across every site. The no-gloves rule exists to stop divers grabbing the rock to stabilise themselves. The no-touch rule is biological. Chasing or handling a turtle causes severe stress and immediately weakens its defences against disease. Look but do not touch.
Turtle Patch: the sunlit parking lot
Turtle Patch anchors the southeast corner of the island. The topography is a flat reef plateau sitting in five to twelve metres of water. The floor is carpeted in enormous overlapping Acropora table corals. I bring divers here in the afternoon to let their bodies release absorbed gas after deep morning dives. It is the easiest diving in Borneo.
Turtle Patch is the island's sofa. The density of resting green and hawksbill turtles here borders on the absurd. I have often settled low over the sand and watched the traffic arrive. Whitetip reef sharks sleep openly on the sand patches while noisy herds of parrotfish crunch through the hard corals around them.
The large coral heads function as dedicated cleaning stations. Turtles line up and hover at an angle while small reef fish systematically pick parasites off their shells. The cleaning station operates like a highly strung pit crew. The fish dart in to clean the shell and the turtle holds perfectly still until the job is done. It is clockwork.
The Drop-Off: the vertical highway
You gear up on the northern beach and walk five steps into the water. The sand slopes gently for a moment and then the floor vanishes. The Drop-Off is a legendary wall plunging six hundred metres straight down into the abyss. It sits directly adjacent to the historical wooden jetty.
The Drop-Off is a vertical highway for the local hawksbills. They commute up and down the limestone face to pick at sponges attached to the rock. You keep the wall on your right shoulder and monitor your depth gauge because the bottom is half a kilometre down. Batfish and giant trevallies school in the shallows under the jetty structure.
The light is the real draw here. I often look up the wall and see turtles silhouetted black against the sunlit surface. Leaf scorpionfish and bright nudibranchs tuck themselves into the crevices alongside the feeding hawksbills. It is a world of tiny creatures wrapped in an open-ocean drop.
Turtle Cavern: the blue cathedral
Just east of The Drop-Off is an opening at eighteen metres. Turtle Cavern is a bell-shaped tunnel leading downward into a wide outer chamber. It is a haunting cathedral of a cave. The entrance frames a perfect blue triangle of ocean water heavily surrounded by schooling trevally and fusiliers.
The cavern earns its name from the floor. The dust is scattered with the skeletal remains of green and hawksbill turtles that swam inside to rest and lost the light. The skeleton of a dolphin rests next to them. They are a permanent reminder of how unforgiving a limestone tunnel is. It demands respect.
Divers can enter this sunlit outer chamber with a local guide. You sweep your fins out and back in small frog-like kicks to avoid kicking up silt and you keep the blue exit at your back. The deeper Turtle Tomb network connecting behind it is a pitch-black labyrinth reserved exclusively for fully certified cave divers on technical setups. Do not cross the line.
The threats you do not see
The reef at Sipadan looks like a permanent sanctuary. The reality in the wider Coral Triangle is far darker. The hawksbill is classified as critically endangered and the green turtle is endangered. Sabah is fighting a quiet war to keep them alive.
The illegal harvest for bekko tortoiseshell remains a brutal reality in Semporna. Researchers surveying Baturua Reef recently documented adult female hawksbills tethered with ropes. Poachers had carved the valuable plates directly off their living shells. It is an industry stripping a live animal of its armour for a bracelet. Pure greed.
A microscopic threat is spreading through the foraging grounds. A devastating tumour disease linked to a herpesvirus called ChHV5 is moving through the population. A recent survey of green turtles at Mabul island found that over five percent carry the virus without showing it. The disease blinds the turtles and starves them. It is a grim death.
The sand itself is becoming a threat. Marine turtles rely on the temperature of the nest to determine the sex of their hatchlings. The pivotal temperature for a green turtle here is a razor-thin window between 29.0 and 29.4 degrees Celsius. When local sands heat up past 31.1 degrees Celsius, the embryos die in the egg before they can hatch. The thermostat is breaking.
The two species handle the map very differently. Satellite tracking shows that our green turtles are homebodies after nesting. They stick to coastal migrations within the Sulu and Celebes Seas and cross the Balabac Straits to forage in Palawan. Hawksbills are marathon swimmers. Tracked hawksbills in the region log average migration distances of over twelve hundred kilometres to reach their feeding grounds.
The permit pool
The island is a fortress. Sabah Parks limits daily access to balance the human traffic against the carrying capacity of the reef. They issue a hard quota of daily permits and snorkellers draw a permit from the same pool as the divers. If you want to see the wall, you need your paperwork locked in long before you land at the airport. No exceptions.
A shorter boat ride to Sipadan leaves less of your day in transit. Compare our resorts or packages to see the logistics or send us your wish-list so we can help match the sites to it. You can check the Sipadan marine life guide for the rest of the cast or look at Mabul muck diving for the macro days.