Matang: Romanticising the Mangroves (2)

ON FISHERMEN AND THE CHARCOAL FACTORY

A small trawler boat crusing by the mangroves of Matang.

A view of Kuala Sepetang fishing village.

Afternoon sees the placid brown rivers of Matang disturbed by incoming fishing boats. The chugging engines tear the calmness of the air previously dominated by whispers of heated updrafts carrying rounds of white bellied eagles (Haliaeetus leucogaster) high in the sky. Crab and prawn pots can be seen stacked highly on these smallish boats. As their bows swing towards wood-planked berths stretching out into the waters from village and warehouses, workers on the boats pulled out blue drums loaded with the day’s catch. The berths were lined with people readying to pull the drums up with metal hooks and strong muscles. The cued thud of the starboard on the berth signals a synchronised hauling of the catch from the deck to the berth in minutes. Once all catches are landed, the captain reverses the boat and head out once more to the sea. In a small frame of time, the fishing village of Kuala Sepetang laid its hands on another couple of tonnes of crustaceans.

 

The distinctive fishing village jetties of Kuala Sepetang.

A boat heading out to sea.

The livery of Kuala Sepetang’s fishing industry for the last 200 years (1) is an enduring testimony of the importance of ecosystem services provided by the mangroves. Mangroves are major nursery grounds for many fishes that inhabit the open waters of the Straits of Malacca (2). During breeding seasons, commercially important fishes such as groupers (garupa; Epinephelus), catfish (keli; Arius), snappers (ikan merah; Lutjanus) and rays (pari; Neotrigon) head into its murky waters to breed (2). The tangled roots and restrictive channels kept large predators away from the vulnerable young fry while they develop into adults.

 A selection of crustaceans such as flower crabs (Portunus pelagicus), mask crabs (Charybdis feriatus), tiger prawns (Penaeus monodon) and a mantis shrimp (Harpiosquilla sp.) found often near mangroves.

These fishes also share their homes with a myriad of other mangrove residents. The celebrated dried shrimp (Acetes spp.) spreaded on the verandas of village houses, drying under the tropical sun, came from the same habitat as the fishes. The greenish-grey mud crabs (Scylla serrata), bounded and packed in rattan baskets were taken from mud banks in the wake of receding tides.

Roofs of Kuala Sepetang fishing village.

The blood clam (Anadara granosa) is a common mangrove mollusc with characteristic red blood (haemoglobin) which aides in its respiration of dissolved oxygen when the tide is far out from its mudflat habitat (4).

Blood clams (Anadara granosa), an indispensable companion of many Malaysian seafood dishes, clang by their thousands in spinning metal clam-washers. Impurities falling out of the washers form a mound beneath it. This is a mix of spiny murex snails (Murex occa, M. trapa), tiger moon snails (Natica tigrina), rock shells (Thais lacera) and sea cucumbers. The first 3 species are blood clam predators and are also increasingly popular on the menu of seafood lovers. This lot is undeniably a section of the mudflat community, which is a unique ecosystem formed by the deposition of nutrient-rich mud on the seaward side of mangrove coasts.

The well-known charcoal factory near Kuala Sepetang. 

Seafood is not the only major industry in Matang’s mangroves. The continual management of mangroves is motivated by the well-known charcoal industry for centuries. The Khay Hor Charcoal Factory is one of the charcoal producers. A tangy vapour of burning mangrove wood greeted me as I was taken a tour of the factory by veteran charcoal-producer Mr. Chuah Chow Aun. Boats holding mangrove logs from allocated logging plots cruises into a canal and unload their cargo. Here, they are processed into charcoal via slow burning in large traditional clay kilns. In the process, strong vapours emitted from the kiln’s outlets are condensed into tannin acid, commercially used for tightening leather but locally used as mosquito repellent. Mr. Chuah explains that the charcoal produced from Matang’s Rhizophora is dense and odourless, a quality attribute that is reflected by the high demand for his charcoal in Japan.

 

The canal where the unloading of mangrove logs takes place.

The kilns where mangrove logs are traditionally processed into charcoal.

Dark coloured Tannin acid is a byproduct of charcoal production.

The abundance of useful species is an important lifeline for the people of Kuala Sepetang. However, these are but a handful of species in the midst of the thousands of others which are very much ecologically-intertwined with them. Mangroves as a whole are an integral part of the tropical land and seascape. Its presence gave rise to a unique ecosystem which in turn, influenced other seemingly unrelated ecosystems such as coral reefs and seagrass beds (2). At a time when Malaysia is increasingly losing its mangroves (3), it is crucial to ensure that Matang's mangrove ecology and interactions are not destroyed or altered significantly under such intensive resource harvesting.  As any visitors will realise, the cultural and industrial successes of Matang hangs on the ecological balance of its mangroves.

  

Scibbles and numbers probably showing charcoal yields. The future of the charcoal industry, like many others in Matang, depends on a responsible, long-term management of mangroves.

References:

(1) Watson, JG 1928, Malayan Forest Records: Mangrove Forests of the Malay Peninsula, Forest Department, Federated Malay States.

(2) Ronnback, P 1999, 'The ecological basis for economic value of seafood production supported by mangrove ecosystems', Ecological Economics, vol. 29, pp. 235-252. (Available from: http://ecosystems.wcp.muohio.edu/studentresearch/climatechange03/productivity/pdf%27s/Mangroveseafoodproduction.pdf )

(3) Chiew, H 2008, 'Mangrove status in Malaysia', The Star, 10 June. (Available from: http://mangroveactionproject.org/news/current_headlines/mangrove-status-in-malaysia )

(4) Davenport, J and Wong, TM 1986, 'Responses of the blood cockle Anadara granosa (L.) (Bivalvia: Arcidae) to salinity, hypoxia and aerial exposure', Aquaculture, vol. 56, no. 2, pp. 151-162. (Available from: http://www.sciencedirect.com/science/article/pii/0044848686900244 )

Matang: Romanticising the Mangroves (1)

Matang is a land of contrasts. It is where numerous mud creeks wind slowly under the endless verdant cover of mangrove stands. A land sheltering clusters of rickety stilt-houses home to generations of fishermen and wood-cutters while serving, at the same time, a refuge for mangrove wildlife. A land whose ecosystem is among the biggest carbon sinks on Earth (1) and yet home to one of the largest charcoal industry in the country (2). Under this paradoxical coexistence, a surprising synergy unveils. This two-part series begins with a visit to the famous mangroves of Matang.

THE MANGROVES

A small river winding among the mangroves of Matang Permeanant Forest Reserve.

The road crossing Matang’s lowlands is peculiarly straight. Lining both sides of the road are the ubiquitous oil palm and the occasional clusters of coconut stands and kampong houses. I strained my eyes to look beyond the blur of passing palms as the car cruises across this unbroken plain, hoping to catch the glitter of mangrove leaves behind the silhouettes of palm fronds, but there were none. At almost 400kmsq, the mangroves of Matang Permanent Forest Reserve are touted as the largest remaining tract of its kind in Peninsular Malaysia (3). But where is it?

 The Matang Permeanant Forest Reserve is an agglomeration of mud-rich estuaries and islands cloaked in mangroves on the west coast of Peninsular Malaysia. 

(Picture source: 4)

Turning around the corner at the end of the road, the car came into full view of a metalled lane walled by an unbroken line of tall mangroves and dense undergrowth. The mangroves have been hiding just behind the oil palms all this while, continuing under the uniform shadow of its thick canopy. Standing at around 10 metres, this unusually tall mangrove Rhizophora apiculata has a straight trunk with branches that does not appear until right at the canopy. Its wide-arched prop roots often share the forest with the sturdy buttress roots of the Leggadai, Brugueira parviflora, which resembles the roots of lowland rainforest dipterocarps. Indeed it almost feels like I’m deep in a rainforest as I pulled into the Matang PFR visitor centre.

 

 A 65-years-old Bakau Minyak, Rhizophora apiculata displayed in situ.

The Piai Lasa, Acrostichum speciosum, is a fern highly adapted to life in the mangrove forest. It is one of the fastest-spreading plants in such habitat and hence, often compete with the planted mangrove saplings (5).

Here is the scene of fierce competition between the fast growing Piai Lasa and the planted Rhizophora saplings.

A typical scene in the Matang mangroves.

The entrance signboard to Matang PFR boardwalk.

Contrary to the putrid, mosquito-infested mangrove stereotype, Matang turns out to be exceptionally neat and fresh! A newly build boardwalk brings visitors deep into the mangrove forest heartland. Bird nest ferns and giant bracket fungi hang on the trunks and branches while fallen logs scatter among meadows of mangrove fern Piai Lasa (Acrostichum areum), Jejuru (Acanthus spp.) and mangrove saplings. The ground here, having thick layers of fallen leaves across the seemingly dry forest floor with occasional puddles of water, bears uncanny likeness to the rainforest. A chance encounter with a freshly dug puddle of mud no doubt made by wild boars (Sus scrofa) further enhances such an impression. Only a faint whiff of salty air reminds me that I am still in a mangrove, at least for a while.

Wild boars (Sus scrofa) often dig pits like these for molluscs and crustaceans (content source: 6)

A giant bracket fungi measuring almost half a metre across.

The spike-adorned Nibong, Oncosperma tigillarium, is a common palm in freshwater swamps and lowland rainforests but can also be found in drier parts of the mangrove (Content source: 7).

The Rotan Bakau (mangrove rattan), Calamus erinaceus is another peculiar plant related to the Nibong (8).

Glancing up to the canopy, I was rewarded with another surprising sight-the crown-shyness phenomena, in a mangrove forest! This is the first time I’ve seen this phenomena outside of the dipterocarp rainforest. It turns out that these were the result of abrasion between swaying branches of neighbouring trees brought by strong winds (9).

Upon closer scrutiny, the ground reveals the marine fauna component of this part of the forest. Grazing on the dead leaves are several species of the peculiar Ellobiid snails. These snails are essentially terrestrial (they are pulmonate snails ie. they breathe air through lungs) in adult form but marine in its larval stages. It requires the tides to wash its eggs into the ocean which its larva will develop and eventually settle on suitable lands in adult form. (10)

The Banded Cassidula snail, Cassidula nucleus, is a common resident of mangroves.

The Judas Ear Snail, Ellobium aurisjudae, is another Ellobiid found in mangroves.

A larger ellobiid, the Midas Ear Snail, Ellobium aurismidae.

This Spotted Littorinid snail, Littorina scabra is another well-known mangrove snail commonly found way above the water line on trunks or even leaves! Despite it able to survive above water for a considerable time, it breathes via gills (11).

A small stream winds through the thick mangrove forest.

As I wander further along the boardwalk and towards the river, the undergrowth gradually gets thinner. Eventually, only a few straws of saplings remain amongst the mingling roots of Rhizophora. Here, vivid claws of red, blue, orange and yellow male crabs vey for attention among the drab muddy background. But it is not my attention that they are seeking, as I found out when they scurried straight into their pencil-thin burrows in the ground as I approach them. Upon sensing little threat I pose to them, they eventually return to the surface and waver their oversize claws once again. This time, several drab looking female crabs approaches them. I was witnessing a mating display. 

The unique prop roots of Bakau Kurap, Rhizophora murconata.

The undergrowth grew thinner towards the river banks.

A male Rose Fiddler crab, Uca rosea with its oversized claw.

However, there is one thing about the mangrove forest that is more surprising than others. There are several clearings in the forest and distinct plots with different stages of young Rhizophora, reminding visitors that this is in fact a mangrove silviculture site. Matang PFR has a long history of mangrove forest management stretching back to 1908 and was one of the field sites where benchmark research into mangrove management strategies took place a century ago (4). There are two primary species planted in this heavily-managed ecosystem- Bakau Minyak, Rhizophora apiculata and Bakau Kurap, R.  mucronata. These species are highly sought-after for charcoal production and various structural uses in local communities.

A plot of young Rhizophora trees.

A specific area of the boardwalk built for mangrove sapling planting.

A propagule of the Brugueira. This is the ‘seedling’ which drops from a parent tree after maturing and often ends up lodge in the mud via its projectile-like end. Tidal waters then triggers roots and shoots to sprout into a sapling. (12)

As I rounded a corner and walked alongside the Rhizophora-fringed river, a distant object splashed into the water instantaneously! Adrenalin suddenly surge through me. Thoughts of getting face-to-face with the saltwater crocodile (Crocodylus porosus) flashed before my eyes as I scanned desperately around to catch a glimpse of this rare and endangered beast. Knowing that this is the region where crocodiles were prime game in the 19^th Century (13), I am always on the lookout for any of their surviving descendants.  A ripple can be seen on the bank, underneath drooping Nipah (Nypa fruticans) fronds. A reptilian head peeked out from the shadows. Sigh, it was no crocodile but a Water Monitor (Varanus salvator).

The water monitor, Varanus salvator swimming along the river bank. It is an omnipresent resident of many habitats stretching from the coastline right up into the mountains, including certain areas of human settlements.

Thick stands of Rhizophora crowd the banks of the river.

Despite continuous disturbance brought on by the silviculture system, it is the biodiversity component that strikes most awe in me. There is no doubt these disturbances altered the natural ecosystem but the resource that contributed to such disturbances-the Rhizophora mangroves, is paradoxically giving the ecosystem a reason to be conserved and be managed sustainably. Inadvertently, this has also buffered various other flora and fauna from ever-encroaching land uses such as agriculture and aquaculture, which have already consumed and heavily disturbed many stretches of this unique ecosystem that exists between the land and the sea.

References:
 (1) Ong, JE 1993, 'Mangroves-a carbon source and sink', Chemosphere, vol. 27, no. 6, pp. 1097-1107. (Available from: http://mangroveactionproject.org/files/resources/Ong_Mangroves%20A%20Carbon%20Source%20and%20Sink_1993.pdf )

(2) pers. comm. Chuah Chow Aun

(3) MTC 2009, 'Matang Mangroves: A Century of Sustainable Management', Timber Malaysia, vol. 15, no. 3, pp. 6-11. (Available from: http://www.mtc.com.my/info/images/stories/pdf/tm-vol-15-3.pdf)

(4) Giri, C, n.d., Matang Mangrove Forest, Malaysia. (Available from: http://earthobservatory.nasa.gov/IOTD/view.php?id=7131)

(5) Watson, JG 1928, Malayan Forest Records: Mangrove Forests of the Malay Peninsula, Forest Department, Federated Malay States.

(6) Baker, N 2012, Eurasian wild pig. (Available from: http://www.ecologyasia.com/verts/mammals/wild_pig.htm)

(7) FAO 2007, Ecocrop: Oncosperma tigillarium. (Available from: http://ecocrop.fao.org/ecocrop/srv/en/cropView?id=8076)

(8) Rattan Species Diversity, 2006. (Available from: http://www.apforgen.org)

(9) Putz, FE, Parker, GG and Archibald, RM 1984, 'Mechanical Abrasion and Intercrown Spacing', American Midland Naturalist, vol. 112, no. 1, pp. 24-28. (Available from: http://www.jstor.org/pss/2425452)

(10) Apley ML 1970, 'Field Studies on Life History, Gonadal Cycle and Reproductive Periodicity in Melampus bidentatus (Pulmonata: Ellobiidae)', Malacologia, vol. 10, no. 2, pp. 381-397. (Available from: http://www.biodiversitylibrary.org/pdf2/002934900047355.pdf)

(11) Chapman, MG and Underwood, MJ 1999, Seashores: A Beachcomber's Guide, Univeristy of New South Wales Press, Sydney.

(12) Mangroves, 2009. (Available from: http://www.wildsingapore.com/wildfacts/plants/mangrove/mangroves.htm)

(13) Maxwell, WG 1907, In Malay Forests, William Blackwood and Sons, London.

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.