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:: Similan Islands Information ::
Ko Similan National
Park
Topography
The Similan National
Park consists of 9 islands comprised of steep granite mountains, beaches &
rock formations of many shapes & sizes. The shorlines of each island are
unique due to the pounding of the sea and erosion of the waves over the years.
The western part of the archipelago lies in the Andaman sea east of the Indian
ocean with the east coast bordering the shorline of Phang Nga province &
lying south of the Mergui Archipelago. The beaches consist of pure fine white
sand and are very clean.
Generalised
Stratigraphy
The Similans are intrusive
granitoids and are part of a north trending belt known as the “western Belt”.
They are characterized by Cretaceous plutons of mixed I (subduction of oceanic
lithosphere) and S (continent – continent or continentmagmatic arc collision)
type granites.
The granites in
this belt occur as small isolated plutons and are characterized by multiple
intrusions of porphyritic biotite-muscovite granite (with K-feldspar
megacrysts). They occur predominantly along the Burmese-Thai border and along
the western part of the Southern Thai peninsular, including Phuket island.
Tin-tungsten mineralization is common in the S-type granite of this belt and has
been mined extensively.
It is believed that the
granite intrusions are possibly related to Mesozoic subduction from the west
between the Indian and Shan-Thai terrain.
The Shan-Thai terrain had
its origins on the northwestern margin of Gondwanaland in the Southern
hemisphere during the lower Paleozoic. The Shan-Thai comprised eastern Burma,
western Thailand, Peninsular Malaysia and northern Sumatra. It is thought that
the Shan-Thai terrain remained attached or close to Australian Gondwanaland
until the early Permian as indicated by early Permian glaciomarine deposits (the
pebbly mudstones of the Kang Krachan Formation or the Phuket group), coolwater
faunas and fauna with northwest Australian affinities and by middle-late Permian
and early Triassic fauna showing affinities to Cathaysialand and to northern
tethys province type. The rifting and displacement in the Paleotethys ocean
resulted in extensive depositions of deep marine facies. In the late Permian the
Shan-Thai collided with Cathaysialand and the suturing of Indochina was largely
completed by the late Triassic.
The distinctive Permian
karstic limestone of the South Western Thailand are known as the Ratburi Group.
The limestones comprise of a transgressive regressive carbonate platform
sequence, interpreted as having been deposited in progressively shallow-water
environments. This ranges from open shoal, marginal platform, to shallow, open,
inner platform and protected lagoon. Brachiopods, corals, crinolids and bryzoas
are the typical fauna associated with the Ratburi Formation.
Structural
Geology
Complex synclinal
structures have been found in the Paleozoic rock in particular the Phuket Group.
The trendnd of syncline / anti cline varies from N-S to NE-SW. Limestones
clearly show folding structures and no rock younger than the Permian Limestone
has been found ontop of these synclines (except colluvium). Faulting occurs in
four directions which are N-S, NE-SW, E-N and NW-SE.
Morphology
The towerlike limestone
hills of Southern Thailand are of the Rathuri Group. The limestone formations
are usually honeycombed by caves and grooves. Other karstic features are
isolated towers, dead-end valleys and subterrabean creeks. The formation of the
limestone hills in southern Thailand is related to the structural setting. The
most recent theories on the morphological development of karstic regions invoke
the ratio between rates of vertical and lateral erosion. In this light,
precipitous limestone hills are indicative of extremely rapid vertical erosion
associated with low water tables and abundance of vertical joint planes.
Climate
The high season begins in
November and finishes at the end of May. The monsoon season then begins around
the middle of May & continues until mid October. The average annual
temperature is 27C but can get up around 34-36C during the hottest part of the
year. The average annual humidity is approximatley 85% with rainfall of around
3,500 millimeters per year. The national park is closed from Mid May till Mid
October.
Flora &
Fauna
Types of forests can be divided into 3 main
characteristics:
Beach Forest –open forest with scattered plants at
approximate height of not over 15 meters such as Terminalia catappa,
Barringtonia asiatica, Callophyllum inophyllum. Small perennials and large shrub
not exceeding 10 meters in height found are Xylocarpus gaugeticus, Herltiera
littoralis, Hibiscus tiliaceus which is a smaller shrub found are Capparis
micracautha, Breynia vitris-idaea Fischer, Pandanus odoratissimus. Grounds
covering plants common in the area are beans, Vigna sp., Spilanthes sp.,
Ischaemum barbatum, Lophatherum gracile, Hoya parasittrica, Asplenium
nidus.
Scrub Forest – habitat for shrubs which can develop on grounds
with soil depth of not exceeding 30 centimeters. A few cacti can be found while
more common shrubs found are Cercus spp., Dracaena spp., Memecylon caeruleum,
Cleistanhus polyphyllus.
Primary Forest – habitation for perennials at a
height of 20 meters or above such as Dipterocarpus costatus, Dipterocarpus
boudii, Shores spp.,. Lower perennials at 15-20 meters in height are palaquium
obovatum, Eugenia denaiflora, Wrightia sp., 10-15 meters in height are
Hydnocarpus ilicifolius, Semecarpus curtisii, Diospyros wallichii. Bambusa sp.,
Calamus longisetus, Plam, Amydrium medium and Bauhinia glauca are also found
with other creepers and parasites such as betel pepper, bauhinia and
orchid.
The most unique vegetation found only on Ko Yai in the Andaman
sea are sapodilla and Nguang Chang Talay while edible plants are Manilkara sp.,
Toumefotia argentia, Bouea oppositifolio, Lepisanthes rubiginosa, Diospyros
wallichii, Neang and Copparis micracantha.
Marine and
Wildlife:
Beneath the sea at Mu Ko Similan National Park lies a
complex ecosystem commonly called the rainforest of the sea: the coral reef. The
major residents of the reef are coral and the closely related sea anemones; of
the Phylum Cnidaria, Class Anthozoa, which contains all radially symmetrical
invertebrate animals. Corals and sea anemones exist as individual polyps living
in either solitary or mostly colonial forms. The polyps of hard corals construct
communal limestone homes which are built up into a multitude of shapes and sizes
eventually giving rise to a coral reef. Soft corals have soft bodies made of
large numbers of identical polyps connected by fleshy tissue (Zooxanthallae).
These soft corals contain small algae within their tissues which are able to
convert the sun's energy into food. This cooperative relationship is known as
symbiosis and also exists in hard corals, clams and other marine organisms.
There are several factors that support good environment for the reef i.e.
temperature, salinity, light, wave and tide, sedimentation and nutrient.
Therefore, healthy coral reef can be found easily in the Andaman Sea comparing
to the Gulf of Thailand. In Andaman Sea, coral reefs are able to classified as
deep water and medium water. For the deep water coral reef grow down to 30 m. In
this case water allows enough light for the algae. This reef type is mostly
found in Similan and Surin islands. For the rest area, medium water coral reef
grow between 8-15 m beneath the surface.
Coral can also be classified to
fall into these structural categories: massive, columnar, encrusting, branching,
foliceaous, laminar and free-living coral. The hard corals found in Mu Ko
Similian National Park are deep water species of mostly staghorn coral types
(Acropora echinata) and the smaller cauliflower shaped types (Seriatopora
histrix). Many other species of marine life co-exist within the coral reef:
Gorgonian sea fans, flower-like soft coral, several species of crabs, spiny
painted lobsters, squid, sponges, sea cucumbers and giant clams.
Above
the sea surrounding each island lies Beach forest, which steadily becomes
Tropical forest further inland. Important tree species include Manilkara sp.
Cordia subcordia, and Tournefotia argentia. A survey conducted in 1992 revealed
that 39 species of birds can be found on the nine islands. Resident species
include the Brahminy Kite, and the White-breasted Waterhen, while migratory
species include the Pintail Snipe, and Grey Wagtail. Temporary migratory species
include the Barn Swallow, Cattle Egret, Watercock, and the Roseate Tern. The
most commonly seen species include the Pacific Reef-Egret, Nicobar Pigeon, Pied
Imperial Pigeon, White-bellied Sea-Eagle, and the Collared
Kingfisher.
The environment of Mu Ko Similian National Park is obviously
that of a small island, wherever you go, you are not far from the sea. Natural
fresh water reserves are few, and as a result, large mammal species cannot
exist. Surveys have revealed that 27 species of small mammals exist within the
park, including 16 species of bats namely: the black-bearded tomb bat, the
lesser false vampire bat, the intermediate horseshoe bat, the lesser bent-winged
bat, and the hairless bat. 3 species of squirrels can be found including the
gray-cheeked flying squirrel. 4 species of rats: the yellow Rajah rat, the
ricefield rat, roof rat and noisy rat can be seen scurrying around as well.
Finally, the more unusal but fairly common residents include the bush tailed
porcupine, common palm civet, flying lemur and the bottlenosed dolphin. 22
species of reptiles and amphibians can be found in the park including the banded
krait, reticulated python, white-lipped pit viper, common pit viper, garden blue
lizard, hawksbill turtle, leather turtle, bengal monitor lizard, common water
monitor lizard, ornate froglet, common asiatic frog, marsh frog, and the common
bush frog. Finally, another most interesting species located in the Similans
island is called the hairy leg mountain land crab. This crab is found in such
large numbers you will be sure to see many just by walking around a bit. No
matter where you are on the island, seeing this creature will be a reminder you
are never far from water.
:: Mergui Archipelao Information ::
Myeik or Mergui
Archipelago, located in southernmost part of Myanmar (Burma), comprises over 800
beautiful islands. Due to its virtual isolation, the islands and surrounding
seas are alive with an amazing diversity of flora & fauna and very beautiful
underwater scenes and marine life
The only human inhabitants in the
area are sea gypsies, called Salon in Myanmar(Burma). They live on boats during
dry season and remain on land during rainy season. They still practice the same
fishing and boat building techniques that have been used for generations
Mergui
Archipelago
Just north of the Surin Islands, an imaginary line
divides Thai waters from Myanmar's Mergui Archipelago. Also known as the
Myeik(Burma) Archipelago, this immense area covers approximately 36,000 sp km
(14,000 sq miles) and included roughly 820 islands. Diving here is still in its
infancy, as the entire region has been off-limits to outsiders since the late
1940s. After several years of negotiation by Phuket dive operators, the
archipelago was opened for tourism in 1997, yet much of the area remains
unexplored.
The islands are similar to their Thai counterparts, with
rugged, high-profile limestone and granite topography. One obvious difference,
aside from the sheer number of Myanmar(Burma) islands, is their unspoiled
terrestrial scenery. Dense brush and rainforest cover most areas above the
high-tide line, while vast stretches of mangroves and magnificent white-sand
beaches are interspersed with rocky headlands, tidal creeks and a few freshwater
rivers. Though several of the larger islands are home to small communities of
Moken 'sea gypsies,' the vast majority are uninhabited and largely untouched by
humans.
Underwater, this region offers scenic reefs, fascinating
topography and prolific fish and invertebrate life. One of the main attractions
for divers is the strong possibility of seeing big animals, especially sharks
and rays. More dependable, however, is the tremendous variety of smaller fish
and reef creatures, including many unusual species, some of which are rarely
encountered in Thai waters. Add to this the allure of diving where few people
have before and you've got all the ingredients for a top-notch dive destination.
Considering the vast number of islands and reefs, many more dive sites are
undoubtedly waiting to be discovered.
The diving here has tremendous
potential, the diving in the Mergui Archipelago is still excellent. Even at sites that were bombed
regularly ( Since Banned), soft corals, anemones and gorgonian fans usually survive undamaged,
as do nudibranchs, cuttlefish, octopuses and other invertebrates. Fish that lack
swim bladders (like sharks, rays and moray eels) also seem unaffected, unless
the explosion is very close. Also, since many fish move from reef to reef, new
fish seem to show up all the time
 Among the geographical beauties of the Union of Myanmar, many
treasures are in the depths existing beneath the archipelago waters to this day.
Myeik Archipelago comprises over 800 islands covering an area of 10,000 sq.
miles. Several expeditions have been undertaken to survey the undersea
ecosystems and biodiversity.
Lumpi island can be reached from Myeik,
about 90 nautical miles southwest, 30 miles west from Bokpyin and 60 miles
northwest from Kawthaung. This beautiful island of Lumpi is totally untouched;
with a rich history of maritime trade and mysticism. The modern day, Mergui
Archipelago, is as it was days gone by. The archipelago is virtually isolated
but you will find the islands and surrounding seas alive with amazing diversity
of wildlife, flora and fauna. Parrots, hornbills, sea eagles Brahming kites and
herons fill the skies. On land, the animal population includes monkeys, wild
cattle, elephants, deer, wild pigs, crocodiles, tigers and rhinoceros.
Crab eating maquekes monkeys can be seen here on the shoreline. The
only human inhabitants to be found in this beautiful area are the Moken sea gypsies, a nomadic
seafaring race.Their life style has changed very little over the years.
The sea gypsies
have been the sole inhabitants of the Mergui Archipelago over the years and they
still use the same fishing and boat building techniques which they have been
using for many generations. Lumpi offers a great variety of breathtaking scenery
and wildlife, with more luxuriant ever green forests, beach and dune forests,
tidal mangroves, magnificent beaches and spectacular coral formation.
The
forests that grow on the island have a variety of both terrestrial and marine
ecosystems and inhabitants. The surrounding waters are rich in bird life, fish
marine, mammals (dolphins) and marine turtles.
Salone, a group living part of the time on a few
littoral area on the fringes of the Andaman sea and part of the time on their
boats, wondering about among the Islands of the Myeik Archipelago in a nomadic
existence that has caused them to become known as the sea gypsies. There are no
more then five thousand Salons left in the world today scattered over the Myeik
Achipelago as well as some parts at the Andaman Sea.
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