What a day!
Just gorgeous weather today. Even late to the office enjoying the scenery....
This is why we live here!!!
First is picture from the viewpoint - that's Khao Lak. On the left, the Andaman Sea, on the right Khao Lak Lamrun National Park. In the middle, us.
A quick one from our shop below....
Have a good day!
One of the most common sharks here in the Similans, the Whitetip Reef Shark is timid. We find these at several of our sites, but they seem to be most frequent visitors at the deep drop offs of Christmas Point and North Point.
The Whitetip Reef Shark (Triaenodon obesus) is generally unaggressive toward humans who invade its environment. Although it often rests in caves during daylight hours, this species is probably the most commonly-encountered shark of the tropical Pacific.
Here in the The Similans, we find the Blacktip Reef shark to be more commonly encountered in the shallows, and the Whitetip to be found in the deeper sites. Because they tend to be in the caves during the day, we can only assume that they are more common at night.
Despite its formal species name, obesus, the Whitetip Reef Shark is rather slender and delicately built. This body form grants it the ability to slither, eel-like into crevices in the reef, where this species is an absolute master at extracting prey. Quiescent during the day, Whitetip Reef Sharks become active and determined hunters at night. Moving over the reef face in loosely organized packs, these sharks systematically poke their blunt heads into each crack and crevice in the reef face in search of prey.
Known prey of the Whitetip Reef Shark includes sleeping diurnal teleosts or hiding nocturnal creatures such as octopuses, soldierfishes, wrasses, and trumpetfishes, which are grasped with its small, tricuspid teeth. Using its ampullae of Lorenzini and uniquely tube-flapped nares, the Whitetip Reef detects its prey primarily by bioelectrical cues and scent. When a hunting Whitetip Reef locates a prey animal within a hole in the reef face, it violently twists and turns to push itself deep into the crevice. Some sharks actually squirm into a hole in one side of a coral head and exit through an opening on the other. During these zealous foraging bouts, Whitetip Reef Sharks have been observed breaking off pieces of coral — sometimes tearing their skin and fins. Although they are primarily nocturnal, Whitetip Reef Sharks can and do feed opportunistically by day.
In addition to electrical and olfactory cues, the Whitetip Reef Shark is also highly responsive to sounds and vibrations. In experiments conducted at the Marshall Islands and French Polynesia, Whitetip Reefs consistently responded to recorded sounds of struggling fish, feeding sharks, and even vocalizations of teleosts. At Eniwetok Atoll, Marshall Islands, artificially generated sounds were found to be most attractive to Whitetip Reef Sharks when they combined low frequency (25-100 Hertz) with varied intermittent pulses every 7.5 to 15 seconds. These sound characteristics correspond well to the irregular sounds and vibrations generated by a fish struggling on the end of a spear or on hook and line. In South Pacific areas where spearfishing is common, Whitetip Reef Sharks respond very rapidly to the sound of a speargun discharge, typically appearing within seconds. Although normally quite placid, this inquisitive species can become persistent and bold when faced with a diver playing or carrying a speared fish — sometimes dashing in to tear an impaled fish from the spear tip.
Due to the abundance of Whitetip Reef Sharks in coastal areas of the tropical Pacific and Indian Oceans, day-to-day life of this species is better known than that of most sharks. Whitetip Reefs are most often encountered during daylight hours while they rest quietly in underwater caves throughout much of the tropical Indo-Pacific or in lava tubes of Hawaiian reefs. But in some locations — such as at Cocos Island and near-shore waters off the Pacific coast of Costa Rica — this species is often seen lying stretched out on the sandy bottom, completely exposed in broad daylight. Sometimes, several of these gregarious sharks are seen lying side-by-side or even stacked on top of one another, like cord-wood. The significance of these diurnal al fresco gatherings is not known, but may have something to do with these sharks being cleaned by small wrasses and at least one species of goby.
Aspects of the private lives of consenting adult Whitetip Reef Sharks have been observed. On several occasions at Rangiroa Atoll, Marshall Islands, two to five mature male Whitetip Reefs were observed following a mature female, possibly attracted by a pheromone ‘perfume’ released by the female to announce her readiness
to mate. Actual copulation in a pair of Whitetip Reef Sharks has been photographed in June 1982 at Molokini Crater, 2.5 miles (4 kilometres) southwest of the island of Maui, Hawaii. Mating took place on the bottom at a depth of 23 feet (7 metres). Both partners’ heads were pressed into the substrate of volcanic rubble and their bodies were aligned parallel to one another, extending upward into the water column at an angle of about 45 degrees. The female Whitetip Reef had fresh cuts above her gill slits and behind her first dorsal fin, presumably from her suitor’s precopulatory ‘love nips’. The smaller male shark had a tight grasp on the female’s left pectoral fin as his left clasper was flexed 90 degrees across his belly and inserted into her vent. The male Whitetip Reef had a swollen and distended left siphon sac — a subcutaneous organ in male sharks that stores the seawater used to flush sperm through the clasper groove and into the reproductive tract of females. After documenting this intimate moment, the underwater photographer and his diving companions opted to leave the mating sharks in peace.
Tagging and telemetry studies have revealed much about the home range and general ecology of the Reef Whitetip Shark. At Mahuta Reef in the Avatoru Lagoon area of Rangiroa Atoll, 75 Whitetip Reefs were tagged, of which 64 (85%) were resighted. Of these 64 individuals, only 8 (13%) were ever resighted beyond Mahuta Reef and of these 8 only 2 (25%) were sighted at other reefs. A year after tagging was completed, about 75% of Whitetip Reefs at Mahuta still bore tags or tagging scars. Even after 3.3 years, some 40% of the sharks had remained in the immediate. This strongly suggests that Whitetip Reef Shark populations are highly stable, with only a trickle of immigration and emigration each year. Telemetry studies of this species at Mahuta have demonstrated that typical day-time range is only 0.02 square miles (0.05 square kilometres) — about the area of Vatican City or about 10 American football fields. At night, however, the same sharks ranged over an area of about 0.4 square miles (1 square kilometre) — an area 20 times as large, or about 100 times the area of a union rugby field. These data suggest that the Whitetip Reef Shark is a definite ‘home-body’, rarely venturing far from a relatively small area.
The Reef Whitetip is one of the three most common sharks on Indo-Pacific coral reefs, the other two being the Blacktip Reef Shark (Carcharhinus melanopterus) and the Grey Reef Shark (Carcharhinus amblyrhynchos). Although these three sharks are widely distributed over the vast expanse of the tropical Pacific and Indian Oceans, their relative distribution over the reef profile is remarkably uniform from place to place. Blacktip Reef Sharks, especially juveniles, are typically found closest to shore, inhabiting the turbid lagoon shallows over sandy plains at depth from 0 to 50 feet (0 to 15 metres). Juvenile Grey Reef Sharks are found in the clearer, deeper waters of the back reef, while adults of this species typically patrol the reef crest and fore reef from the depth of about 65 feet (20 metres) down to a depth of about 330 feet (100 metres). Both species are most active at dawn and dusk, accomplishing most of their feeding during these twilight hours when schooling diurnal fishes are most vulnerable.
Neatly nestled between the crepuscular Blacktip Reef and Grey Reef sharks, Whitetip Reefs typically haunt the reef flats and shallower parts of the fore-reef at depths of 35 to 100 feet (10 to 30 metres). Although it can extend its range from the intertidal to at least 130 feet (40 metres), the Whitetip Reef manages to coexist with the Blacktip Reef and Grey Reef Shark by feeding primarily at night and specializing in extracting prey from cracks and crevices in the reef face that are all but inaccessible to these other sharks. By inhabiting different depths and ecological niches, the slender Whitetip Reef Shark reduces competition for food resources with other sharks sharing its habitat.
Much of this was written by R. Aidan Martin for the ReefQuest Centre for Shark Research. Lots of great information for the shark Freak in all of us.
Wikipedia is a great source of information with some really nice links as well for follow up research. We Used them, Elasmo-divers and several books, but primarily "Sharks and Rays of the World" by Debelius.The Blacktip Reef Shark is one of the more common sharks we see on our dives. While they have the outline of the typical sharks, they are often quite small - less than 1.5m. While many of the Sharks we have tend towards the deeper sites, this is one that can be seen be snorkelers. So this is a shark actually best seen from our Day Trips, rather than the Liveaboards.
Carcharhinus melanopterus
Blacktip Reef Shark
Description & Behavior
Carcharhinus melanopterus
Blacktip Reef Shark
melanopterus (Quoy and Gaimard, 1824), is a small shark measuring up to 1.8 m with a short, bluntly-rounded snout, oval eyes, and narrow-cusped teeth. There are 2 dorsal fins, no interdorsal ridge. Juveniles (<70>World Range & HabitatHere is a lot more information about Manta Rays. 
These guys are really cool. More than that, they are majestic - no other word for it. They move so smoothly and such grace.
February and March.Still we see them throughout the year and at almost all dive sites. The odds are highest for encounters at Koh Bon and Koh Tachai. But we have seen them at almost every site on the Similans at some point - diving or snorkeling.| Recognition | A gigantic devilray with gracefully sculpted, falcate pectoral 'wings', paddle-like cephalic lobes projecting forward from the front of the head (actually extensions of the pectoral fins, supported by radial cartilages), and a very broad, rectangular mouth at the end of the head (a mouth type known as 'terminal'), pebble-like teeth in the lower jaw but not the upper. They don't have teeth in the traditional sense. |
| Color | Variable, ranging from black, greyish blue, to greenish or reddish brown above (black color morph sometimes with whitish, triangular shoulder patches), and nearly black, white with various degrees of greyish blotching (the precise pattern of blotching has been used to identify individuals), to almost pure white below; one albino specimen has been reported. |
| Size | Disc width at birth about 4 feet (1.2 metres); maximum disc width 22 feet (6.7 metres), possibly larger (reported to widths of up to 30 feet or 9.1 metres), maximum recorded weight 3 100 pounds (1 400 kilograms). Click here for amazing birth video... |
| Distribution | Circumtropical (around the globe, generally between 35 degrees north and south latitude), including: off southeastern South Africa, Madagascar, Mozambique, Tanzania, Kenya, and Somalia; in the Gulf of Aden, Red Sea, Arabian Sea, and the Bay of Bengal, off Burma (Myanmar), Thailand, Malaysia, Indonesia, northern Australia, New Guinea, Solomon Islands, Philippines, Kampuchia, Viet Nam, China, Korea, and southern Japan; off Guam, Palau, Yap, New Caledonia, Fiji, and Hawaii; off southern California to northern Peru, North Carolina to southern Brazil, the Azores, Senegal to Liberia. |
| Habitat | Occurs most often in nearshore waters (mainly over continental and insular shelves, but occasionally over deep water), near coral and rocky reefs; swim by flapping their large pectoral fins and are usually encountered near the surface or mid-waters of lagoons or seaward reefs, particularly near surge channels; in Australian waters, Mantas sometimes migrate into temperate waters; they are capable of rapid speed and juveniles sometimes leap well clear of the water, landing with a loud slap (adults drive their bodies only partway out of the water and then fall back into the sea, sometimes performing 2 or 3 of these jumps in succession); often host to one or more discfishes (especially the White Remora, Remorina albescens) and sometimes observed in association with dolphins, seabirds, sharks, and other rays (notably the Spotted Eagle Ray, Aetobatus narinari); these rays actively seek the services of cleaner wrasses (Labroides spp.), often hanging over or swimming near "cleaning stations", sometimes several lining up to wait their turn. |
| Feeding | A gigantic filter-feeder, preying on planktonic crustaceans and small schooling bony fishes; filtering mechanism consists of transverse plates of pinkish-brown spongy tissue that bridge the gaps between successive gill bars (cartilaginous skeletal elements that support the gills); when feeding, the cephalic lobes are unfurled and spread (directing and sometimes apparently scooping plankton-bearing water into the mouth), the animal often swimming in slow somersaults (vertical loops) that are repeated over and over (this behavior may keep the rays within a patch of particularly rich feeding, and may also concentrate planktonic prey to facilitate feeding); most often encountered as solitary individuals, but members of this species often aggregate in regions offering predictably rich feeding (off Yap, in the western Caroline Islands) — with up to 50 individuals clustered in the same general area, but not forming true schools. The geology of Koh Bon ridge is particularly conducive to these habits. Sadly we only groups of 5 or 6 |
| Reproduction | Ovoviviparous, with each of the pups wrapped in a thin-shell that hatches inside the mother, later to be born alive; one specimen harpooned off North Carolina expelled a pup (with one pectoral fin wrapped above its body, and the other wrapped below) in mid-trajectory when it leaped, a behavior which may represent spontaneous abortion (ejected prematurely due to capture stress) or be part of normal birthing (If so, what a dramatic way to enter the world!); litter size 1 to 2 (usually 2) pups, with birthing apparently occur in relatively shallow water, where the young remain for several years before expanding their range farther offshore; mating behavior in this species has recently (July 1997) been filmed off the Ogasawara Islands, Japan, and featured one or more males rapidly chasing a female for 20—30 minutes, after which one male nips the tip of either of the female's pectoral fins (which severely impairs her swimming), moves to her ventral surface, and inserts one of his claspers (paired intromittant organs, developed along the inner margins of the pelvic fins) into her cloaca (vent), thereby mating belly-to-belly; the male may hold onto the (much larger) female's pectoral fin for several minutes after removing his clasper, eventually letting her go free. |
| Age & Growth | Growth of newborns is apparently very rapid, virtually doubling the disc width at birth during the first year of life; males may mature at a disc width of about 13—15 feet (4.0—4.5 metres), females at a disc width of about 16—18 feet (5.0—5.5 metres), but this needs confirmation; no data on age at maturity for either sex. |
| Danger to Humans | Minimal unless attacked (especially harpooned) or otherwise startled, but the enormous size and power of this ray should invite respect. Not only is there a danger from any contact (don't try to touch 1 tonne animals in the wild) but actually trying to ride one brings huge consequences in many ways. DON'T Touch them |
| Utilization | Formerly hunted commercially by harpoon from small boats off eastern Australia and in the Sea of Cortez (Gulf of California), this species is now rarely hunted; places where these rays can be reliably encountered have spawned substantial dive-tourism industries; seemingly inquisitive, individual Mantas sometimes approach and even solicit attention from divers, apparently enjoying the tactile stimulation provided by the bubbles from scuba exhaust; in areas frequented by divers, however, Mantas often become very wary of divers and cease to approach them. When approached rapidly, some individuals roll onto their backs (perhaps to keep the offending diver in sight?), sound (dive), and swim away rapidly, righting themselves only when some distance away; another behavioral response to approach by a diver from the side is curving one pectoral fin toward its back and the other toward its belly — forming an S-shape in cross-section — tilting its dorsal (top) surface toward the diver (possibly a defensive response?); in areas where divers touch Mantas, the rays often develop pinkish skin lesions that may persist for months (apparently these lesions occur where human touch has removed the protective mucus that coats the rays' skin). When diving or snorkeling with these magnificent, supremely graceful rays, resist the temptation to touch them and avoid obstructing their looping glide path while they feed. Not only bearing in mind the currents that they usually associate themselves with, it's also a great idea to neither pursue nor intrude on thier path. They frequently return to the same spot. Patience is the key to encounters with these magnificent creatures |
| Remarks | The Manta Ray is one of the very largest and least-known elasmobranchs; although stingless, Manta Rays are actually very closely related to stingrays (family Dasyatidae), the Manta Ray, together with 9 species of devil rays (genus Mobula) comprising a subfamily (Myliobatinae) within that group; until recently, a number of Manta species were considered valid (Manta alfredi, M. ehrenbergi, M. hamiltoni), but all are now tentatively regarded as a single, world-wide species; this matter is currently under investigation by comparison of genetic samples from several populations, which should (hopefully) settle the matter once and for all. |
Similan Islands and Manta Rays 
One of the most amazing, and to me the most fascinating creatures we have here are the Manta Rays that call this area home. I had never seen them before and even now, after several years of diving with them - they are enthralling to see. Their movements are reserved and majestic. I still find them to be one of the most alien of our creatures.
While doing research for this I learned a lot more than I had expected. They are even more fascinating now. Read how they reproduce - wow! Similar to How eagles do, but drifting across the oceans - weightless. Ahem...
I was really amazed at how little was known about them. Something so large, so beautiful and something that we see so frequently - it was baffling how little there was about them. The first birth ever recorded only happened this year!
Below is a great FAQ written by R. Aidan Martin for the ReefQuest Centre for Shark Research. Because there seems to be regional variations and new information, I will include comments in italics.
Where are Manta Rays found?
Mantas are found world-wide in tropical to warm temperate seas. On the Similans they are most frequently found at Koh Bon, Koh Tachai and randomly at other sites.
Does the Manta Ray have any teeth?
Yes, Mantas have about 300 rows of tiny, peg-like teeth, each about the size of the head of a pin. The crown of each tooth has a blunt surface with three weak ridges. These teeth are often indistinguishable from the denticles (scales) inside the mouth and are not used for feeding. They may play a role in Manta courtship and mating (see below).
How do Manta Rays reproduce?
Like sharks and other rays, Mantas are fertilized internally. Male Mantas have a pair of penis-like organs — called claspers — developed along the inner part of their pelvic fins. Each clasper has a groove through which sperm is transferred to a female Manta's body, where fertilization takes place. During courtship, one or more male Mantas chase a female for prolonged periods. Eventually a successful male grasps the tip of one of her pectoral wings between his teeth and presses his belly against hers. Then, the male flexes one of his claspers and inserts it into her vent. Copulation lasts about 90 seconds. The fertilized eggs develop inside a mother Manta's body for a lengthy but unknown period that may be 9 to 12 months or more. One to two pups are born per litter, but no one knows where or when Mantas give birth. There is one report from North Carolina of a baby Manta being born as its mother was in mid-leap after being harpooned, but this may not be typical. Mother Mantas may take a year off between pregnancies to re-build her energy stores.
How big is a newborn Manta Ray and where have they been found?
Based on the smallest free-swimming members of this species, newborn Mantas are about four feet (1.2 metres) across. Very few newborn Mantas have been reported and we know almost nothing about where they are born. While there is still little known about where they prefer to give birth, there was recently a live birth at an aquarium in Japan
What is the size of the largest Manta Ray ever found?
Records of giant Mantas are notoriously difficult to verify. The largest reported in the scientific literature measured 22 feet (6.7 metres) across and there is one report of an individual 30 feet (9.1 metres) across. But most Mantas encountered by people are about 12 feet (4 metres) across.
How long do Manta Rays live?
No one knows how long Mantas live. Based on known lifespans of closely related (but much smaller) warm-water rays, Mantas may live up to 25 years or so.
Why do Manta Rays have different color patterns?
Mantas vary enormously in color pattern on the shoulders and, especially, the undersurface of
the body. It is not known what functions — if any — these differences hold for Mantas, but they are very useful for researchers in distinguishing one individual from another. The shape and extent of the shoulder patches, the precise pattern of spots and blotches on the undersurface, and the lifetime pattern of scars form a pattern of markings as unique as a human fingerprint. Manta markings can be photographed and filed in an organized way to allow cataloguing all individual Mantas in a given area. There are also intriguing regional differences in Manta color patterns. For example, specimens from the eastern Pacific often feature dusky to mostly black undersurfaces, while those from the western Pacific are typically snow white underneath.
| |
Have Manta Rays ever killed anyone?
There are numerous reports, mostly anecdotal, of harpooned Mantas leaping on small vessels and smashing them or their occupants. Some of these cases may have resulted in the death of one or more people due to crushing or drowning, but it must be borne in mind that the animal was simply trying to defend itself. Divers have sometimes been injured accidentally while trying to ride or photograph Mantas from too close. But there is no record of an unprovoked Manta attacking or injuring a person. A similar question - has anyone ever killed a Manta? An animal with no teeth, no defense mechanism that eats plankton.
What preys on Manta Rays?
Only large warm-water sharks, such as the Tiger Shark (Galeocerdo cuvier), are known to prey upon Mantas. The head marine Biologist from the Phuket aquarium claims that they are predated upon by killer whales! Yes we do have a pod of killer whales that migrates through the area!
Is it ok to ride Manta Rays?
No wild animal is benefited by being ridden., and Mantas are no exception. Riding a Manta increases its swimming effort — using up calories that might have been better used growing, reproducing, escaping predators, or healing wounds — and may stress the animal unduly. While riding Mantas, people have scraped their skin, gone too deep, risen too fast, or fallen off and been injured accidentally. Simply touching a Manta may remove some of the mucus coating that protects the animal from marine infections. Last, but not least, some Mantas clearly do not like being touched and may speed away, ending the encounter by sheer distance. For all these reasons, touching or riding Mantas is to be avoided. We also see it as extremely vain to think that one of the most majestic animals on earth should be ridden. Not only is it a clear and public display of ones ignorance, but should be reported to marine park rangers. The operator that allows this activity should also be reported, and as things don't always get accomplished through the courts, please post the name and details of the operator on forums like lonely planet and scuba forum.
We feel VERY STRONGLY that interference of any kind with the marine environment is shameful and to be avoided.
Why are Manta Rays bodies flattened?
Mantas bodies are flattened from top-to-bottom because their ancestors were, too. Mantas are derived from stingrays, which are flattened bottom-dwellers that swim by undulating their expanded pectoral fins. This flattened body form is advantageous for hiding in the bottom sediment, making it difficult for predators to see partially buried stingrays. During the course of their evolution, Mantas lost the stinging barb and their pectoral fins developed into graceful, flapping wings, but their flattened body shape remained.
Do Manta Rays migrate?
Given the scattered nature of their planktonic food, it is very likely that Mantas migrate. But little is known about where they travel and when. Each autumn (March-April) at Ningaloo Reef, of the coast of Western Australia, Mantas appear in large numbers, apparently to take advantage of the rich feeding afforded by the mass spawning or corals and other reef creatures that takes place at this time. Where the Mantas go when they leave Ningaloo is not known. Manta movement patterns are presently being studied by tagging and sonic telemetry at numerous locations, including Ningaloo Reef, the Ogasawara (Bonin) Islands, Hawaii, and the Sea of Cortez.
Do Manta Rays sleep?
No one knows. In vertebrates (backboned animals), sleep is characterized by a profound change in brainwaves. This has never been demonstrated experimentally in Mantas or any other elasmobranch (shark or ray). Actively swimming sharks and rays, such as the Manta, are believed to swim constantly, never stopping from birth to death. Although it is feasible that some parts of the brain shut-down while the parts of the brain responsible for coordinating swimming movements stays awake, this has not been demonstrated experimentally.
Are Manta Rays social?
Apart from courtship and mating (which is quite elaborate, see above), Mantas do not appear to be particularly social. Mantas frequently aggregate at rich feeding sites and cleaning stations, but there is little evidence of social interaction among them. Actively predaceous animals — such as lions, wolves, sharks, and dolphins — often establish social hierarchies (structures) and signals. Outside breeding season, most passively grazing animals — such as cows, deer, antelopes, and apparently Mantas — show little awareness in one another other than avoiding collisions.
Are Manta Rays more active by day or by night?
Mantas are most commonly seen during daylight hours because that's when most observers are most active. We have virtually no idea what Mantas do at night or how active they are. Manta courtship (see above) seems to feature prolonged chasing, which would be best accomplished in clear, open water during the day. Mantas may feed most actively at night, when many planktonic creatures rise surfaceward, providing a rich bounty on which Mantas may feed. Beginning about an hour after dark at a certain seaside hotel on the Kona Coast of Hawaii, groups of Mantas are often observed feeding on krill and other planktonic organisms concentrated in the hotel's underwater lights. Unfortunately, this spectacle has largely ceased, possibly due to too much interaction from the throngs of excited divers and snorkellers who converged on the feeding Mantas.
How deep do Manta Rays swim?
Divers have observed Mantas as deep as 100 feet (30 metres), but no one knows how deep they can swim.
What is the difference between mantas and mobulas?
Mantas and mobulas (also known as "devil rays", of which there are 9 species) are similar in form, sharing paddle-shaped cephalic lobes and gracefully curved pectoral wings. Mantas grow much larger than mobulas. Mantas reach widths of at least 22 feet (6.7 metres), while most mobulas are 3 to 10 feet (1 to 3 metres) across. Mantas and mobulas are most readily distinguished by the position of the mouth: in Mantas, the mouth is terminal (located at the front of the head), while in mobulas the mouth is subterminal (located underneath the head, as in many sharks).
What are cephalic lobes and what is their function?
The forward-pointing, paddle-like organs at each corner of a Manta's mouth are termed "cephalic lobes". They are basically forward extensions of the pectoral wings, complete with supporting radial cartilages. Mantas have been observed using their cephalic lobes like scoops to help push plankton-bearing water into their mouths. When Mantas are not actively feeding, the cephalic lobes are often furled like a flag ready for storage or held with their tips touching like the swinging doors of an Old West saloon. Either of these cephalic lobe positions may reduce drag during long-distance swimming.
Why do Manta Rays sometimes jump out of the water?
Mantas may leap completely out of the water for a variety of reasons. They may do it to escape a potential predator or to rid themselves of skin parasites. Or they may leap to communicate to others of their own species — the great, crashing splash of their re-entries can often be heard from miles (kilometres) away. It's anyone's guess what they may be trying to communicate. Leaping male Mantas may be demonstrating their fitness as part of a courtship display. Since these leaps are highly energetic and often repeated several times in succession, they may simply represent a form of play.
Have Manta Rays ever been exhibited in an aquarium?
Very few aquariums have the enormous tanks and filtering capacity needed to display a full-grown Manta. Although there have been many valiant attempts to display Mantas in aquaria, most specimens refuse to feed and die within a few hours or days of being deposited in a tank. The Expo Aquarium, in Okinawa, Japan, has successfully maintained Mantas for as long as 36 days. Despite the failures of the past, several large aquaria continue to refine and test capture and transport methods toward the goal of maintaining a healthy Manta in captivity indefinitely. It seems that this is no longer true. Again, the trapping and caging of such creatures is a real shame.
Are Manta Rays hunted anywhere in the world?
In the 1990's, targeted harpoon fisheries in the Philippines and off the Pacific coast of Mexico decimated resident populations. Due to the scarcity of catches, Mantas are rarely targeted in these locations today. Mantas are sometimes ensnared in drift or set nets, particularly in tropical parts of the western Pacific and Indian oceans. These catches are rarely reported, so it is difficult to assess the threat posed to manta populations by these "incidental" captures.
Do Manta Rays have any monetary value?
Mantas are valued commercially for their tasty meat, sandpapery hide, and oil-rich liver. A Manta in captivity is worth a small fortune to any public aquarium with the facilities to display it, a reality that drives a small but recurrent harvest in Japan and possibly other areas. The monetary value to the diving and snorkeling industry is enormous. By observing one manta, we will generate thousands of Euros into the local economy. Additionally this will be recurring income, rather than a one time catch. Please don't purchase any products from Mantas or other species while in Thailand.
Are Manta Rays in danger of extinction?
We don't know. Mantas seem to be fairly abundant in some areas, rare or absent in others. Until we understand the extent and dynamics of Manta stocks, there is no way to assess their conservation status. Based on their low birth rate, Mantas are probably highly vulnerable to sustained fishing pressure and habitat degradation. This likelihood would seem to favor a cautionary approach to Manta exploitation and management until such time as we have the sound scientific data to make a more informed assessment of this species' risk of extinction.
Why are Manta Rays important?
So little is known about the basic biology and life history of Mantas, little can be said about their importance from a scientific or ecological standpoint. It can be argued that Mantas are important because they add to the beauty, diversity, and mystery of our world. Without Mantas, our planet would seem a significantly poorer place.
Mantas are most frequently seen in February and March with plenty of sightings outside that time. We offer daytrips and liveaboards that offer great chances of seeing them.
Happy Lagoon Bungalows...
A lot of our guests stay here, because it's convenient and easy. While we do have several other resorts this one has the most character.
This is one of the more interesting resorts in Khao Lak.
Near to the beach, but not close enough to charge too much money for the rooms. They offer
ordinary service, but the location is really convenient and the rooms are a reasonable deal for the price
The Restaurant is middle of the road, nothing too interesting or odd, just ordinary (mind you it's Thailand, so when here is ordinary, it's pretty good - But when the food is good...It's the BEST)
What makes this resort so odd is the designer. Someone got a little bit weird after the Tsunami (they are on high ground and lost no staff or customers), and first they built a 10 meter mock of James Bond Island (in Phang Nga bay). They built it in the middle of little bond.
But when the bulk order of Cement came in they went nuts.
Little ponds,
fake grottoes,
and a bar that would have made the Flintstones feel right at home.
Built entirely out of cement, but with an American Indian theme, it is one of the strangest things in town.
The Totem pole, the peculiar caves/tables. Well it's best experienced in person.
The Happy Lagoon does not have a website (though some very eager Germans have set one up claiming to be them), they can be contacted by phone or email Contact us for more information.
The rates are reasonable, starting at 400 Baht for the cheap rooms up to 1500 for the bungalows. They may change prices for the 2007-2008 season.
Khao Lak Diving
Similan Liveaboards
Dive Safely
Wicked Diving, Khao Lak brings you more of our Similan Marine Life articles with this one on the Grey Reef Shark.
While they are around, we don't see them as frequently as some of our other sharks - Leopards and Black tips. this is more to do with the geology than anything else. They tend to be a bit more open and in sites we don't dive as often or that we spend as much time in. Such as Deep off Christmas point and off Koh Tachai
They are also pretty timid when it comes to humans.
GREY REEF SHARK
Order: Carcharhiniformes
The grey reef shark was originally described as Carcharias amblyrhynchos by Bleeker in 1856. He later changed this name to the currently valid name of Carcharhinus amblyrhynchos. The genus name Carcharhinus is derived from the Greek "karcharos" meaning sharpen and "rhinos" meaning nose. Synonyms used in previous scientific literature that refer to the grey reef shark include Carcharias nesiotes Snyder 1904, Carcharhinus menisorrah Whitley 1944, Galeolamna fowleri Whitely 1944, Galeolamna turfiensis Whitely 1949, Galeolamna coongoola Whitely 1964, and Carcharhinus wheeleri Garrick 1982.
English language common names include grey reef shark, blacktail reef shark, black-vee whaler, bronze whaler, gray reef shark, gray shark, gray whaler shark, longnose blacktail shark, shark, and whaler shark. Other common names from across the world include 'anga (Tongan), bagea totoho (Gela), grijze rifhaai (Dutch), grys rifhaai (Afrikaans), ikan yu (Malay), jarjur (Arabic), kortneus-swartsterthaai (Afrikaans), mago (Niuean), malie-aloalo (Samoan), marracho enlutado (Portuguese), nga-man-nee (Burmese), pako mej (Marshallese), pating (Tagalog), qio dravu (Fijian), raira (Tahitian), requin à queue noire (French), requin bar (French), requin blanc (French), requin dagsit (French), requin gris (French), te alava (Tuvaluan), te bakoanimarawa (Kiribati), tiburón coralero rabinegro (Spanish), and tiburón de arrecifes (Spanish).
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The grey reef shark may be taken by longline shark fisheries and are valued for their fins that are used in shark fin soup. It is also utilized for human consumption and fishmeal. However, this species often occurs out of the range of most commercial shark fisheries.
Conservation
The gray reef shark, Carcharhinus amblyrhynchos, is listed as Lower Risk (LR/nt) on the IUCN Red List of Threatened Species:
LOWER RISK (LR) - A taxon is Lower Risk when it has been evaluated, does not satisfy the criteria for any of the categories Critically Endangered, Endangered or Vulnerable. Taxa included in the Lower Risk category can be separated into three subcategories:
1. Conservation Dependent (cd). Taxa which are the focus of a continuing taxon-specific or habitat-specific conservation program targeted towards the taxon in question, the cessation of which would result in the taxon qualifying for one of the threatened categories above within a period of five years.
2. Near Threatened (nt). Taxa which do not qualify for Conservation Dependent, but which are close to qualifying for Vulnerable.
3. Least Concern (lc). Taxa which do not qualify for Conservation Dependent or Near Threatened.
The grey reef shark is vulnerable to overfishing due to its restricted habitat, small litter size, and relatively late age of maturity. These factors, along with an increase in unmanaged fishing pressure, make this shark vulnerable to threats. However, at this time there is not enough data on the grey reef shark to analyze the status of populations.
The grey reef shark is currently listed by the World Conservation Union (IUCN) as "Near Threatened". More fisheries data is required for future assessment. The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
Danger to Humans
Although it is one of the most aggressive sharks, the grey reef shark will usually only attack a person when it is threatened. Even so, it has been responsible for 7 unprovoked attacks resulting in no fatalities according to the International Shark Attack File. If cornered or threatened is some way, the grey reef shark will display threat behavior explicitly. It will raise its snout, depress the pectoral fins, and arch its back while swimming with an exaggerated sway. If the threat continues, the shark will move with lightening speed, delivering quite bites prior to retreating. Although the bites are often serious, they are rarely fatal. This species of shark is also more likely to attack while solitary rather than schooling perhaps due to an increased feeling of vulnerability.
Guiter Shark AKA Shark Ray
Much of this information is from the Australian Museum, as there is little information on this rare shark....
While they are not common, they are found on the outer edges of Richelieu Rock and sporadically at other deeper sites. As they are more benthic we see them only at the bottom of the reefs.
We see they infrequently, and if you read the link above about their numbers, you'll see why.
The Shark Ray is a very distinctive, deep-bodied fish which is found widely in the Indo-Pacific.
The upper surface of this species is a blue-grey color with white spots. There is a large blue-edged, black blotch above each pectoral fin and dark bands between the eyes. Unfortunately the specimen in the images has faded and these markings are not visible. This colouration is often not as distinct in large individuals which may only have faint markings.
Some of the most obvious features of this species are the wide, blunt snout, the large thorns on the bony ridges on the head and the large spiracles (the holes in the head behind the eyes). The tail of this species is much longer than the disc. The Shark Ray belongs in the family Rhinchobatidae (the guitarfishes). Two of the characters that separate the guitarfishes from other fishes are the well developed lower caudal fin lobe and the distinct demarcation between the head and pectoral fins. Both of these characters are clearly visible in the top image.
The Shark Ray is a very distinctive, deep-bodied fish which is found widely in the Indo-Pacific.
The upper surface of this species is a blue-grey colour with white spots. There is a large blue-edged, black blotch above each pectoral fin and dark bands between the eyes. Unfortunately the specimen in the images has faded and these markings are not visible. This coloration is often not as distinct in large individuals which may only have faint markings.
Some of the most obvious features of this species are the wide, blunt snout, the large thorns on the bony ridges on the head and the large spiracles (the holes in the head behind the eyes). The tail of this species is much longer than the disc. The Shark Ray belongs in the family Rhinchobatidae (the guitarfishes). Two of the characters that separate the guitarfishes from other fishes are the well developed lower caudal fin lobe and the distinct demarcation between the head and pectoral fins. Both of these characters are clearly visible in the top image.
The Shark Ray is not dangerous to humans. It uses its flattened pavement-like teeth to feed on crabs and shellfish.
Some more nice pictures of the Gran Palace in Bangkok in July, 2007.
It is a very chaotic place, the layout is not so easy to understand and while the area is huge, many of the buildings feel cramped.
Rather than the overall majesty, it is in the details that I find the most interesting things.
The little statues throughout, the ornamentation.
And, as you can see, visiting on a sunny day! That's not too common in this huge city. So lots of shiny pictures .
Trying to add some substance to all this talking! Here is a nice map showing Khao Lak in relation to the Surin Islands. As the Crow flies, it's about 80 Km, but currently we aren't leaving directly.
With the best snorkeling and jungle around, this is always a staff favorite. Really scenic. The k is good, but not as exciting as the Similans. So we usually only go there for snorkeling and camping
You will also see that Koh Tachai and Koh Bon are very convenient From Khao Lak. Richelieu Rock is little bit far, so we often depart from Kuraburi and that's a straight shot out and back.
Just above the Surin Islands is the border with Myanmar/Burma. It's always strange to realize how close we are.
It always sounded so exotic and far away - Burma. Yet it's just a couple of hours away...
Here are a couple of scenery pictures to tide you over until next season. I know I can't wait.
The first picture is the channel between the two largest islands. You can see the water is clear and it is even better than that, Average temperature of 27c (about 150 Farenheit - like bathwater!)
Here is a longtail parked outside the national park headquarters.
Hmm...not many other National Park offices look like that.
Khao Lak Diving
Similan Liveaboards
Dive Safely
This image was in a hospital on Bangkok. I don't think I will ever use a sad toilet again. Or angry toilet. Or depressed toilet. Nope
Only happy toilets for me.
Khao Lak life - a few things we find in the house!
It's been a while since we added to the collection of bug pictures...
Here are a few new ones to add.
The first one is a beetle that is fairly common. Very nice, as the shell is a green metallic color. They are the bug that usually lands on people who've never been here before and you here the screams from 200 meters away. They are pretty big, but totally harmless.
The other Feller we have here is one of the many versions of grasshopper that we have. these actually look like leaf and as you can see are pretty big.
They even have the veins down their backside, just like a leaf.
Khao Lak Weather - July
It has been a wet month. Lots of rain, but that's what July is famous for. With a couple of different weather patterns roll through it made the diving non-existent for the last three weeks. The past couple of days have really cleared up and we reckon that it goes on further like this - we will have some reasonably flat seas soon.
But when the clouds clear it
is amazing....here's sunset last night...
Khao Lak Diving
