The Perhentian Muck Diving Experience

The Northern most archipelago of the East Coast of Peninsular Malaysia, Pulau Perhentian (meaning: Stopover Islands) consists of the smaller Pulau Susu Dara in the North-west and the two larger islands of Pulau Perhentian Kecil (centre) and Pulau Perhentian Besar (South-east).

Rarely seen nudibranchs, countless seahorses anchoring on every protruding object on the seafloor, strange stares of frogfishes shrouded by soft corals. Such encounters on a single dive are every diver's and macro-photographer's dream especially those that have been touched by the amazing diversity of macro-life of Lembeh Straits in North Sulawesi, Indonesia or the increasingly popular Bali "black sand" dive sites, among many other localities.

However, discovering such a site in the North-eastern corner of Peninsular Malaysia sounds like an impossible news! After all, one can obviously see the distribution of muck-dive sites fitting well within or in the proximity of the Coral Triangle region: Bali, North Sulawesi, Semporna Islands, The Philippines, Eastern Indonesia, Timor, Papua New Guinea and many others. So, is it plausible that such sites exist far beyond the Coral Triangle?

The gin-clear waters of Pasir Panjang(Long Beach), Pulau Perhentian Kecil.

That was what our group responded to when our dive guide made his 2-year-old discovery known over a scrumptious dinner. It had been a tiring and fruitless dive off the coast of Pulau Perhentian Kecil that afternoon; We found nothing but silt and dead corals with an occasional, meagre covering of polyps on half-smothered whip corals. His account of that dive was a revelation.

The dead and destroyed coral heads along Pulau Perhentian Kecil's finging reef system: a direct victim of indiscriminate use of boats on shallow reefs.

The next day, arming with depth detectors and enthusiasm to the brim, we found ourselves navigating away from a small-headland off the coast of Pulau Perhentian Kecil at a snail's pace. With the boat engine chugging at high decibels, our dive guide told us from the top of his lungs how difficult it is to locate this site. It's little wonder as this mini sea mount, a smallish peak of an underwater dune, is quite a distance from the island and is under 28m of churning water.

The beautiful morning in Pasir Teluk Aur, Pulau Perhentian Kecil on the day of our dive.

Strong currents sweeping from the mainland 20km away constantly brings high levels of silt and nutrients to the sea mount, which contributed to the diversity of the benthic (bottom-dwelling) organisms. The currents, however, could be a bane to divers as well. If we were lost somewhere between the surface and the bottom in the currents, we could end up surfacing off the shore of Kelantan or Pattani in the North, or worst, in the middle of South China Sea!

Finally, the depth detector beamed a 28m reading and we scattered off gearing up our equipment before plunging together into the cerulean waters. The first few minutes seemed forever, as we fought arduously against the current while trying to maintain contact with others in the group under rapidly declining visibility.

As visibility came close to 3 metres, I have finally hit the sea bed. A quick survey indicate a terrain not unlike typical muck dive sites: a silty carpet of crushed and piled shell-rubble. There are no hard corals as the turbidity of the water discourages growth. Only some turfs of soft corals Sceleronephyta sp. were found.

A more detailed scanning of the area revealed overturned soft corals and highly disturbed sea bed. A glaring trail of destruction left by trawlers, and it's within the Pulau Perhentian Marine Park perimeter! Somewhere at the back of my mind, I was contemplating the possible incursion of seahorse fishermen into restricted territory were fueled by the growing demands of the traditional medicine market. This is the case for the once abundant populations of seahorses elsewhere around the Peninsular, as some studies have shown (see reference). Were the Perhentians already under pressure from such unsustainable fisheries?

Putting such preoccupations aside, I scoured the sediment loaded bottom for interesting critters that we were after. After several strokes of my fins and I am face to face with my first find.

A beautiful juvenile Sea slug (a.k.a. nudibranch), Armina semperi, devouring morsels of coral polyps of Sceleronephyta sp.

Just an arm length away, a much larger specimen of the same species was seen foraging for it's well known prey-The Sea Pen.

Indeed, just a metre away, lies a fully outreached Sea Pen, Virgularia sp., capturing plankton with its feathery filters called rachis.

As we continued exploring, a fiery pompom like organism crawling on the sand caught my sight. As I was about to maneuver into my photographing position when our dive guide frantically signaled me over to his side! It was the same critter I saw moments ago. This time I could get a closer look at its features.

It's Rory's Flabellina, an unidentified nudibranch (but with a common name) first discovered

also in Perhentian and recorded in the Great Barrier Reef as well.

We counted another two, then three and more all around the vicinity! They seemed to be common in this locality!

The backs of these nudibranchs are covered with "pompom" like structures known as cerata which could be detached from the body like the tail of a gecko, when harassed.

We were ecstatic by now, scrambling around and fixing our eyes on the shell grit carpet. We saw some bristle worms, Chloeia sp. common to such silty habitat. In addition to that, a scurrying heart urchin caught our attention as well. Most divers are familiar with the usually sessile or passive Diadema Urchins, Diadema sentosum. However, it is a rare privilege for divers to observe the rapidly moving bristles of this particular heart urchin has utilised in its movements.

The Heart Urchin, Eurypatagus ovalis, is a rare sight on most diving occasions as it mostly inhabits sandy and muddy substrates away from typical dive conditions.

As we were busy with our own finds, our diver guide signaled us for the critter we have been crying for.

Clinging tightly to a clump of Sceleronephyta sp. soft coral, is the timid Spiny Seahorse, Hippocampus spinosissimus. We cautiously moved around it so as not to over stress it.

After some photographing, we proceeded on.

Scanning various other possible microhabitats, we discovered some equally interesting crustaceans and their camouflaging behaviour.

A well known commensal urchin crab, Zebrida adamsii, seeks shelter within the pink spines of an unidentified urchin.

Another tiny denizen of soft corals is the Squat Lobster, Galathea sp. . Contary to it's name,

this critter is more closely related to hermit crabs than lobsters.

Another well camouflaged soft coral-inhabiting Procelain Crab, Lissoporcellana sp. hiding under the branches of Dendronephyta sp. at the centre of this picture.

As my air gauge closes in towards the 100 bar, I made the last dash to locate as many critters as possible. I have managed to find some more interesting slug species:

A cousin of Rory's Flabellina, this is the Red-lined Flabellina or Flabellina rubrolineata displaying its own set of violet-tinged cerata.

The exquisitely decorated candy-like Ornate Cadlinella, Cadlinella ornatissima, is a good macro-photography subject.

The widespread yet photogenic Serpent Pteraeolidia, Pteraeolidia ianthina, always equips itself with stinging cerata to ward off predators.

Sometimes, symbiotic single celled organisms called zooxanthellae can be found within the cerata, synthesising food from sunlight to supply its host.

On first sight, this may look like any unassuming patch of sand and grit.

However, a slight current generated by one of our unsuspecting diver revealed the 20cm long Wonderous Melible, Melibe mirifica ! I'm elated having never seen such a giant nudibranch before.

With 28m of water above us and our limited air reserve, we motioned everyone to start a gradual ascend up the water column. As much as we were unwilling to leave such a productive site, the discovery did not end there! Midway up the ascent, we chanced upon many rarely seen planktonic tunicates! This includes the swirling, snake like Colonial Salps, which is a chain of pelagic tunicates and the other are large (~10cm), solitary individuals simply known as Salps. And perhaps the most interesting part is: These two are of the same species! They are simply in a different stage of life. (Check out this link for more information)

Photographing the almost transparent solitary Salp, Salpa maxima, is a great challenge and the best shot I could obtain only shows its outline.

After 50 minutes of exhilarating discoveries, we emerged out of the water and beaming with smiles. There's still something to look forward in Pulau Perhentian after all! The corals and water visibility may not be comparable to those of many other East Coast Islands but Pulau Perhentian offers an alternative that is worth exploring, at a comparably lower cost than established muck dive sites elsewhere.

However, it was a rather bittersweet moment for us too: The absence of frogfishes and the scare number of seahorses we saw was a world way from what our dive guide first set his eyes on years ago. This confirmed my initial suspicion. Clearly, some fishermen have been breaching deep into Pulau Perhentian Marine Park. They have been plundering the last populations of seahorses to satisfy the unsustainable traditional medicine market.

As our boat chugged back to the dive centre, a flotilla of trawlers emerge over the horizon, heading towards the islands. Are we willing to lose this invaluable asset again?

One of the many shallow sea trawlers operating from Kuala Berang across Pulau Perhentian, on the mainland.

Reference and Further Reading:

1. C.K. Choo and H.C. Liew, 2005. Exploitation and Trade in Seahorses in Peninsular Malaysia. Malayan Nature Journal 2005, 57(1), 57-66.

2. U. Sachidhanandam, R.C. Willan, L.M. Chou, 2000. Checklist of the Nudibranchs (Opisthobranchia: Nudibranchia) of the South China Sea. The Raffles Bulletin of Zoology, 2000 Supplement No 8: 513-537. National University of Singapore.

3. N. Coleman, 2008. Nudibranchs Encyclopaedia: Catalogue of Asia/Indo-Pacific Sea Slugs. Neville Coleman's Underwater Geographic Pty. Ltd., 2008.

4. S. Harding, J. Comley, M. Helgeveld, N. Coltman, P. Raines, 2003. Malaysia Reefs and Islands Conservation Project 2003: Report of the Marine Pilot Phase. Coral Cay Conservation Ltd.

5. Reef Check Malaysia: Annual Survey Report 2007. Reef Check Malaysia, 2007.

6.Dr. G. R. Allen, R. Steene, 1994. Indo-Pacific Coral Reef Field Guide. Tropical Reef Research, 1994.

Pulau Sipadan: The Story So Far

Pulau Sipadan- Jewel of the Celebes Sea

It has amazed thousands of visitors around the world with its serene coral reefs and profusion of marine biodiversity beyond imagination ever since renowned aquatic explorer,

Jacques Cousteau first penetrated into its depths in awe and wonder that is reflected in his well-versed quote- "I have seen no other places like Sipadan, 45 years ago, but now no more. Now we have found an untouched piece of art" during his expedition across the Sulu-Celebes Sea. Superlative descriptions have been a common "trademark" for Pulau Sipadan. Everyone who have visited this 12 hectares island carry their own accounts of adventures, each as amazing as the other. However, underlying all these colourful stories is one that many have not ventured into yet, a story that is as grand as its coral reefs - The Story of the Evolution of Pulau Sipadan into the island we know today.

Semporna town near Pulau Sipadan. The flatland across the shallow strait is Pulau Bum Bum and the tall imposing peaks behind it is Pulau Gaya and Pulau Boheydulang.

Beyond the acknowledgement of Pulau Sipadan as a oceanic, volcanic sea mount in tourists brochures, little else about its origin is mentioned. So, to fill this information gap that some visitors (including me) may wonder about, I've done a small online research to analyse and share this particular island's history with everyone. The following may not be a complete description of the island's formation but nevertheless, it sheds some light to this legendary island's origins.

To fully understand the geological history of Pulau Sipadan, we have to look at the bigger picture that is Sabah, the continental tip of Northern Borneo. Turning the clock back to more than 65 million years ago, much of North Borneo was submerged under deep waters. As the Tertiary period (65 million - 2.588 million years ago) begins, the first lands can be seen breaking the cerulean waters in the form of a chain of islands that resembles much more of a growing underwater mountain range of what is now the tallest in Borneo- the Crocker Range. As time progresses, clouds bringing storms and rains washed the slopes of these majestic mountain-islands, thus distributing alluvial deposits along the coast until these islands became linked.

Mount Kinabalu, at 4095m, is the tallest peak in Crocker Range at present day.

Kinabatangan Delta of present day Borneo gives us a glimpse of what Central Borneo used to be like.

The Eurasian Plate is where the Sundaland (the shallow, light blue area) is. The Philippine plate can be seen as a dark (deep) area off Northeastern Borneo.

The movement of Philippine plate against the Eurasian plate north of Sabah further pushes the mountain range higher and higher while creating a wide floodplain to the east with soil runoff from the highlands during the Miocene period (23.03 - 5.33 million years ago). Meanwhile, the same Philippine plate in the southeastern end of North Borneo starts to drift apart from the Eurasian "mainland", causing a rift and sets off the red hot lava bursting out of the cracked Earth crust from the deep magma below. Soon, the deep seas off the developing floodplains east of Crocker Range (now Central Sabah) were boiling hot with lava and pumice bursting out of the surface all the time. This will soon form most of Eastern Sabah, in which the Semporna Peninsula will emerge from the thick clouds of volcanic ashes.

Remains of ancient volcanoes in Tawau, west of Semporna.

Volcanic rocks of Tawau indicates the region was once highly active in volcanic activity.

Low tides exposes ancient volcanic pumice and rock deposits (dark brown areas) along mainland Semporna and Pulau Bum Bum.

Across the 100m tall developing volcanic cones along Semporna Peninsula, ashes spews and radiate out into the ocean and the ancient floodplains of Central Sabah, joining nearby islands and expanding its landmass. However, further out in the deep ocean off the edge of Eurasian Plate, an undersea volcano far removed from the bustling volcanic activity miles from it, silently build in height. Forwarding the frame in a year per second, one would see steam rising out from the deep Celebes Sea and then, a dark mass of rock and pumice pops out of the surface and extends in width and height. Pulau Sipadan is born. Since it is separated from mainland Semporna by deep waters, the lowland sediments of Semporna never made it to Sipadan.

Volcanic rocks exposed on Pulau Menampilik off Semporna.

The chain of islands off Southeastern Semporna with prominent exposed volcanic rocks.

Sometime later, the lava flows and plumes disappeared and volcanoes silenced. Clumps of greenery previously existed only in areas of least volcanic activity flourished and spreaded across the landscape. Gradually, the dark rocks of past ages got smothered in rainforests and mangroves, only occasionally protruding as hardened lava cones at higher peaks. Ashes not covered by vegetation end up being washed away by rains and wave action of the sea. As time progresses, the ice age of the Holocene (approximately 12000 years ago) arrives. As if a plug in a basin of seawater is being pulled, sea levels bordering the peninsula dramatically retreated 120m below sea level. Thus, "raising" the badly worn volcanic peaks of Semporna some 100m above that era's shoreline. Across the narrow band of water, Sipadan stood as a lonely, weathered and extinct volcano draped in lush forests on its slopes and coastal grasslands along it's coasts. During this time, some ancient fauna and flora might have migrated to the island through the deep but short passage of sea. There may be corals fringing the ancient coast as well.

Fertile soils encourage rapid growth of rainforests across the volcanic slopes of the mountains on mainland Semporna.

Manado Tua of North Sulawesi, Indonesia. Pulau Sipadan was once similar in appearance to this island when it was a volcanic mountain island many millenia ago.

Bukit Tengkorak with a volcanic outcrop, near Semporna town. The sign of an ancient volcanic land.

Fertile lands on the southeastern tip of Semporna Peninsula is the testimony of the volcanoes around the area.

Corals are the building blocks of Sipadan's limestone.

Approaching 6000 years before present day, the ending of ice age marked another dramatic event- the increase in sea level or mass-flooding. Once again, lowlands shrinked and forests of the past disappeared below the waves. The seawater soon reached present day levels at 6070 years before present, only to exceed another tenths of metres of height for the following millenia. Thus, the cone became completely submerged. Corals started to form at the top most part of the seamount, growing outwards slightly below sea level. Before long, the sea levels retreated again, exposing the limestone reefs to the atmosphere and creating habitat for forest recolonisation. During this period of emergence, parts of the limestone eroded to form a complex cave system complete with stalactites and stalagmites which will be known as the Turtles' Tomb or Cave due to the high numbers of unfortunate turtles trapped and died in the labyrinths of this cave. What happens next will define Sipadan's present day characteristics.

Coral-fringe islands is now part of Semporna's modern feature after the sea level rise.

The island chain in the foreground used to be high and dry with grasslands dominating valleys between them and the sea as well as mainland Semporna (background).

During the exposure of limestone, this may be what Sipadan looked like. Picture taken in Nusa Penida, Bali, Indonesia, an island made of raised coral limestone.

The submerged cave entrance to Turtle's Tomb.

Crevices like these may be the access routes to caves lying deep inside Sipadan limestone.

Being on a mobile, active edge of the Philippine plate, it so happened that Sipadan slides along the growing tectonic plate and the limestone forest began to submerged again, probably eliminating the terrestrial ecosystem all together. Then, polyps of modern corals settled on the ready-made reefs of craggy limestone to expand as a reef and form the strange shape of a "mushroom" along the top perimeter of the seamount. Up above water, the reefs slowly give way to a sand bank which accumulates and grows as time passes. Birds and storms bring driftwood, sea beans, plants and animals to colonise the sandy island. Finally, the ecosystem of coastal forests and coral reefs reached their climax that is Pulau Sipadan today.

The sand bar formed near Semporna show what modern Sipadan was like in the initial stages of development.

As sand accumulates, the land mass increases and vegetation flourishes as shown here in Pulau Mabul, near Sipadan.

Driftwood washed up by storms brings in many flora and fauna from nearby terrestrial ecosystems.

The product of millenia of colonisation by terrestrial flora and fauna- the dense coastal forest of Pulau Sipadan.

The famous vertical drop off of Sipadan. Could this be the upper part of the "mushroom" structure?

Diving along the ancient limestone cliff.

Sipadan today as seen from above (Google Earth).

Indeed, Pulau Sipadan has gone a long way since becoming a little lava-spewing bump at the edge of the Philippine Shelf and Eurasian Plate to the grandeur of today. Not surprisingly, the story of this tiny island in the Celebes Sea does not end here. Maybe Sipadan is going to expand its landmass? Or rather swept below the waves by climate change induced sea level rise? Or, as some joked, topple over into the abyss of the Celebes due to excessive pressure on the seamount by the "mushroom" coral limestone? (Note: The last theory is mend to be, well, a joke!)

Reference:
1.Charles S. Hutchison, 2006 The Unique Geology of Sabah (North Borneo). University of Malaya, Kuala Lumpur. (click here)

2. JED Fox. General Geology of Sabah (excerpt). Sabah Forestry Department. (click here)

3.Intercoastal Zone Management Project, 1998. Sabah Coastal Zone Profile. Town & Regional Planning Department Sabah. (click here)

4.Allagu Ballaguru and Gary Nichols, 2003. Tertiary stratigraphy and basin evolution, southern Sabah (Malaysian Borneo). Journal of Asian Earth Sciences V. 23, Iss. 4: 537-554

5.Mohd Harun Abdullah, Mazlin B. Mokhtar, Sanudin Hj. Tahir and Almah Bt.
Awaluddin, 1997. Do Tides Affect Water Quality in the Upper Phreatic Zone of a Small Oceanic Island – Sipadan Island, Malaysia? Environmental Geology 29(1/2):112-117

6.Ahmad Zaharin Aris, Mohd Harun Abdullah, Kim Kyoung Woong, 2006. Hydrochemical Analysis on seawater intrusion of small carbonate islands: Manukan and Sipadan, Sabah. Proceedings of the 2nd Southeast Asian Natural resources and Environmental Management Conference, kota Kinabalu, Nov. 21-23, 2006, pp.40-44