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The giant moray (Gymnothorax javanicus) is in terms of body mass the largest of the moray eel species, from the family Muraenidae.

General Description
As the name suggests, this is a large eel, reaching up to 3 metres in length and 30 kilograms in weight. While juveniles are tan in colour with large black spots, adults have black specks that grade into leopard-like spots behind the head and a black area surrounding the gill opening, there is a greenish base colour with dark speckling, and a more pale area around the face. In some species, the inside of the mouth is also patterned.
The body is long and heavy set but despite this is very flexible and moves with ease.
The dorsal fin extends from just behind the head along the back and joins seamlessly with the caudal and anal fins. Most species lack pectoral and pelvic fins, adding to their serpentine appearance. Their eyes are rather small so giant moray eels tend to rely on their highly developed sense of smell, lying in wait to ambush their prey.
Their jaws are wide, framing a protruding snout. Most possess large teeth that are designed to tear flesh or grasp slippery prey items and they are capable of seriously wounding humans.
Giant moray eels secrete a protective mucus over their smooth, scaleless skin which in some species contains a toxin. Morays have much thicker skin and high densities of goblet cells in the epidermis that allows mucus to be produced at a higher rate than in other eel species. This allows sand granules to adhere to the sides of their burrows thus making the walls of the burrow more permanent due to the glycosylation of mucins in mucus. Their small circular gills, located on the flanks far posterior to the mouth, require the moray to maintain a gap in order to facilitate respiration.
Typically, only its head is visible sticking out of the reef, but occasionally it will spend time with its head and much of its body extending up into the water column. It is usually a solitary species, but on occasion two giant morays may share the same crevice or cave.

Eating
Giant moray eels are carnivorous and feed primarily on other fish cephalopods, molluscs and crustaceans. It also engages in cooperative hunting with the roving coral grouper. The invitation to hunt is initiated by head-shaking. The rationale for this joining of forces is the ability of morays to enter narrow crevices and flush prey from niches not accessible to groupers. This is the only known instance of interspecies cooperative hunting among fish. Cooperation on other levels, such as at cleaning stations is well-known.
Morays rest in crevices during the day and hunt nocturnally, although they may ensnare small fish and crustaceans that pass near them during the day.
The giant moray eel has an unique way of swallowing their prey, this is due to their alien-like second set of jaws (or pharyngeal jaws) which they have in the back of their throat (very nicely visible in the video above!). When they lash out at a prey, they grab it with their first set of jaws first, then with the second while holding it with the first set. When the second set of jaws has a hold on the prey it pulls the prey into the digestive system. The giant moray eel is the only animal in the world which uses its pharyngeal jaws while hunting.
Its natural prey consists mainly of fishes, but it also eats crabs, shrimp and octopuses. This species will also eat other species of eel.

Reproduction
Giant moray eels travel up to 4,000 miles to breed, a journey which can take up to seven months. During that time it is believed that the eels do not eat. Instead, they use their body fat and muscle tissue for nutrients. Adults die after breeding.
Courtship among compatible morays begins when water temperatures reach their highest, and they begin sexual posturing in the form of gaping widely. Then the morays will wrap each others’ long slender bodies together, either as a couple or 2 males and a female. They simultaneously release sperm and eggs in the act of fertilisation, which signals the end of their relationship.
On hatching, the eggs take the form of leptocephalus larvae, which look like thin leaf-shaped objects, that float in the open ocean on ocean currents for around 8 months. Then they swim down as elvers to begin life on the reef and eventually after three years become a moray eel, living between 6 and 36 years
Scientific studies have shown hermaproditism in morays, some being sequential (they are male, later becoming female) and others are synchronous (having both functional testes and ovaries at the same time) and can reproduce with either sex depending on species in a natural life cycle.

Where to find the Giant Moray Eel
Giant moray eels are found worldwide in tropical and temperate seas, particularly in relatively shallow water among reefs and rocks, in lagoons and seaward reefs, as well as in estuarine areas.
This immense moray hides in reef interstices, under ledges and in caves on reef walls and they live at depths of up to several hundred metres.
We encounter Giant Morays on many of our trips, but they are particularly common on dives done form our Similan Liveaboard trips

Conservation
This species of moray are fished, but are not considered endangered. This is due in no small part to their toxicity. Ciguatoxin, the main toxin of ciguatera, is produced by a toxic dinoflagellate and accumulated up through the food chain, of which moray eels are top, making them dangerous for humans to eat. This fact was apparently the cause of death for King Henry I of England, who expired shortly after feasting on a moray eel.

The giant moray eel is frequently thought of as a particularly vicious or ill-tempered animal. In truth, they hide from humans in crevices and would rather flee than fight. Giant morays are shy and secretive, and attack humans only in self defense or mistaken identity. Most attacks stem from disruption of a giant moray’s burrow (to which they do react strongly), but an increasing number also occur during hand-feeding of giant morays by divers, an activity often used by dive companies to attract tourists. They have poor vision and rely mostly on their acute sense of smell, making distinguishing between fingers and held food difficult; numerous divers have lost fingers while attempting hand feedings. For this reason the hand feeding of giant moray eels has been banned in some locations.
The moray’s rear-hooked teeth and primitive but strong bite mechanism also makes bites on humans more severe, as the eel cannot release its grip even in death and must be manually pried off.

The saltwater crocodile, (Crocodylus porosus), also known as the Estuarine or Indo-Pacific crocodile, is the largest of all living reptiles.

General Description
An adult male saltwater crocodile’s weight on average is 409 to 1,000 kilograms and length is normally 4.1 to 5.5 metres. However, mature males have been known to exceed 6 metres and weigh more than 1,000 kilograms, and this species is the only extant crocodilian to regularly reach or exceed 4.8 metres. Weight can vary enormously based upon the condition and age; older males tend to outweigh younger ones since they maintain prime territories with access to better, more abundant prey. This species has the greatest sexual dimorphism of any modern crocodilian, with the females being much smaller than males. Typical female body lengths range from 2.3 to 3.5 metres. The largest female on record measured about 4.2 metres. The mean weight of the species as a whole is roughly 450 kilograms.
Saltwater crocodiles have very large heads. A pair of ridges run from the eyes along the center of the snout. The eyes, ears, and nostrils are located on the same plane on the top of the head, allowing for it to see, hear, and breathe while almost totally submerged. The eyes have a special second pair of eyelids known as the nictitating membrane. These eyelids are clear and protect the eyes while underwater. The ears, situated behind the eyes, have flaps which also close while underwater. The jaws are heavy set and contain between 64-68 teeth. The teeth in the upper jaw are perfectly aligned with those in the lower jaw. The fourth tooth on each side of the bottom jaw is larger than the other teeth and is visible when the mouth is closed.
Juvenile saltwater crocodiles are yellow in colour with black stripes and spots. As they mature, the colour becomes paler and the stripes indistinct until they disappear. Adults are dark in colour with light grey areas. The belly is yellowish and the underside of the tail is grey near the tip. Dark bands are located on the lower flanks. The hide lacks osteoderms (bony plates) and is ideal for tanning in the leather industry. Scales are oval in shape and the scutes are small. The colouration of this species differs in regions; some areas have juveniles much lighter in colour than elsewhere.
Saltwater crocodiles can swim at 15 to 18 miles per hour in short bursts, but when cruising they go at 2 to 3 mph.
Saltwater crocodiles are considered very intelligent and sophisticated animals. They communicate by barks and are thought to display four different calls, including a high-pitched distress call performed by juveniles in a series of short barks. Threat calls consist of a hissing sound made at intruders. The courtship bellow is heard as a long, low growl.
Saltwater crocodiles use thermoregulation to maintain body temperatures. They cool themselves in water and warm themselves in the sun.

Eating
The saltwater crocodile is an apex predator capable of taking nearly any animal that enters its territory, either in the water or on dry land. They are known to attack humans who enter the crocodiles’ territory. Juveniles are restricted to smaller animals such as insects, amphibians, crustaceans, small reptiles, and fish. The larger the animal grows, the greater the variety of animals it includes in the diet, although relatively small prey (especially fish) make up an important part of the diet even in adults. Large adult saltwater crocodiles can potentially eat any animals within their range, including monkeys, kangaroos, wild boar, dingos, birds, domestic livestock, pets, humans, wild boar, bats, and even sharks.
Generally very lethargic, a trait which helps it survive months at a time without food it loiters in the water or basks in the sun through much of the day, preferring to hunt at night. Saltwater crocodiles are capable of explosive bursts of speed when launching an attack from the water.
It usually waits for its prey to get close to the water’s edge before striking, using its great strength to drag the animal back into the water. Most prey animals are killed by the great jaw pressure of the crocodile, although some animals may be incidentally drowned.
Its typical hunting technique is known as the “death roll”: it grabs onto the animal and rolls powerfully. This throws any struggling large animal off balance, making it easier to drag it into the water. The “death roll” is also used for tearing apart the large animals once they are dead.

Reproduction
Breeding and raising of the young saltwater crocodiles actually happens in freshwater areas, the female lays between 40 – 60 eggs in a nest made from plant matter and mud on a river bank which is elevated to avoid loss from flooding during the rainy season. The mother guards the nest, even preventing it from drying out if necessary by splashing it with water. The eggs take 90 days to develop. The sex of the young saltwater crocodiles is determined by the incubation temperature. Below 30°C the hatchlings will be female, and above 32°C they will be male.
When eggs are about to hatch the baby crocodiles make chirping sounds, and the mother helps them by digging them out of the nest. Then she takes the hatchlings to the water’s edge in her mouth and from here on watches over them until they are able to look after themselves.
Not all of the newborn crocodiles will reach adulthood, less than 1% will not survive. Predation by turtles takes its toll in the early days, and later on the juveniles are often killed and eaten by territorial mature males.
Newly hatched saltwater crocodiles measure about 25 to 30 centimetres long and weigh an average of 70 grams. Males reach sexual maturity at around 3.3 metres at around 16 years of age, while females reach sexual maturity at 2.1 metres and 12–14 years. The average lifespan for the saltwater crocodiles is up to 70 years.
The territorial behaviour of the male saltwater crocodiles forces the young crocodiles out of the region in which they have been raised. They have to find an unoccupied territory for themselves. If they are unable to do that they will either be killed or be forced out to sea. Here they will move around until they find another river system.

Where to find Saltwater Crocodiles
Saltwater crocodiles generally spend the tropical wet season in freshwater swamps and rivers, moving downstream to estuaries in the dry season, and sometimes travelling far out to sea. Crocodiles compete fiercely with each other for territory, with dominant males in particular occupying the most eligible stretches of freshwater creeks and streams. Junior crocodiles are thus forced into the more marginal river systems and sometimes into the ocean. This explains the large distribution of the animal. 
While these species do have a fairly large habitation area, we only visit a few of those areas – as their habitat and our diving rarely overlap. Some of our expeditions have brought us to their habitat, but we take care not to intrude. They are not encoutnered at all aboard our Similan Liveaboard

Conservation
Extensive hunting for their hides (the most valuable of all crocodile skins) has reduced the population of saltwater crocodiles numbers to a critical level. Their reputation as a man-eater doesn’t help either. The two facts combined have resulted in crocodiles numbers dwindling to almost zero in countries that previously had healthy populations.
When saltwater crocodiles were finally made a protected species their numbers slowly recovered. Today several breeding programs exist, for skin and meat production. For this crocodile eggs are collected from the wild. The egg collection so far hasn’t shown any detrimental effect on the population numbers.
Aggressive trapping of problem crocodiles and their removal to crocodile farms has reduced the numbers of conflicts between humans and reptiles.
Population estimates range from 200,000 to 300,000 worldwide, and they are considered at low risk for extinction. But saltwater crocodile hides are valued above all other crocodilians, and illegal hunting, habitat loss, and antipathy toward the species because of its reputation as a man-eater continue to put pressure on the population.

The saltwater crocodiles are the largest crocodilians in existence, in addition to being highly opportunistic and territorial predators when compared to other crocodilians. They have a strong tendency to treat humans in their territory as prey, and have a long history of attacking and consuming humans who stray into their territory. Therefore, the only safe policy for dealing with saltwater crocodiles is to avoid their territory whenever possible as they tend to be highly aggressive when encroached upon

Olive ridley sea turtles, Lepidochelys olivacea (Eschscholtz, 1829), aka Pacific ridleys, are small, hard-shelled marine turtles, one of the two species of the genus Lepidochelys, and a member of the Family Cheloniidae. It is closely related to the Kemp’s ridley, with the primary distinction being that olive ridleys are found only in warmer waters The olive ridley sea turtle was named after H.N Ridley FRS, who was on the island of Fernando de Noronha, and in Brazil in 1887.

General Description
The olive ridley gets its name from the olive coloration of its heart-shaped top shell (carapace) and is one of the worlds smallest of the sea turtles, with adults reaching up to 60 centimetres in length and weighing anything from 36 to 49 kilograms. The species may be identified by the uniquely high and variable numbers of vertebral and costal scutes along its carapace which is bony, without ridges and has large scutes (scales). In addition, the vertebral scutes also show frequent division, as do the scales on the dorsal surface of the head. The prefrontal scales, however, usually number two pairs.
Their smooth shells and paddle-like flippers help them speed through the water as fast as 24 kph. These long-distance travelers have been known to swim up to 4,828 km in one year.
Males have longer thicker tails than females and well-developed curved claws on the forelimbs.
Although olive ridley sea turtles cannot withdraw their heads into their shells, the adults are protected from predators by their shells, and thick scaly skin on their heads and necks.
The turtles spend almost all their lives submerged but must breathe air for the oxygen needed to meet the demands of vigorous activity. With a single explosive exhalation and rapid inhalation, olive ridleys can quickly replace the air in their lungs. The lungs are adapted to permit a rapid exchange of oxygen and to prevent gasses from being trapped during deep dives. The blood of olive ridley sea turtles can deliver oxygen efficiently to body tissues even at the pressures encountered during diving.
The species can rest or sleep underwater for several hours at a time but submergence time is much shorter while diving for food or while escaping predators. Breath-holding ability is affected by activity and stress, which is why sea turtles drown in shrimp trawls and other fishing gear within a relatively short time.
Although olive ridley sea turtles move swiftly in the ocean, they are slow and defenseless on land. Male sea turtles almost never leave the water. Female sea turtles leave the ocean only to lay eggs and, for most species, nest only at night. Females of most species may nest every two to three years.

Eating
The olive ridley is omnivorous, meaning it feeds on a wide variety of food items, including algae, lobster, crabs, tunicates, mollusks, shrimp, and fish. They can dive to depths of about 150 metres, to forage on benthic invertebrates. and they possess powerful jaws that crush their prey which enables the turtle to swallow their meal.

Reproduction
The olive ridley has one of the most extraordinary nesting habits in the natural world. Large groups of turtles gather offshore next nesting beaches. Then, all at once, vast numbers of turtles come ashore and nest in what is known as an arribada. During these arribadas, hundreds to thousands of females come ashore to lay their eggs. At many nesting beaches, the nesting density is so high that previously laid egg clutches are dug up by other females excavating the nest to lay their own eggs.
There are many theories on what triggers an arribada, including offshore winds, lunar cycles, and the release of pheromones by females. Despite these theories, scientists have yet to determine the actual cues for ridley arribadas. Not all females nest during an arribada, instead some are solitary nesters. Some employ a mixed nesting strategy. For example, a single female might nest during an arribada, as well as nest alone during the same nesting season.
Females nest every year, once or twice a season, laying clutches of approximately 100 eggs on average. Incubation usually takes between 50 to 60 days.
Nesting can take between one and three hours. After a female turtle drags herself up the beach, she hollows out a pit with her back legs and deposits anything from 50 to 200 eggs the size of golf balls. When the last egg is laid, the turtle covers the eggs with sand, tamps down the sand with her tail and flings more sand about with her flippers to erase any signs of the nest.
After about two months, the hatchling turtles emerge at night. The light reflected off the water from the sky guides them to the sea. These days, car headlights, street lamps, or lights on buildings near the beach cause some hatchlings to travel in the wrong direction. Waiting herons make fast meals of other hatchlings. Any babies still on the beach in the morning are easily picked off by predators or die in the hot sun. It is thought that when the surviving hatchlings reach sexual maturity, at about 15 years of age, they return to the beach where they hatched to lay their eggs.

Where to find Olive Ridley Turtles
The olive ridley is mainly a pelagic sea turtle, but has been known to inhabit coastal areas, including bays and estuaries. Olive ridleys mostly breed annually and have an annual migration from pelagic foraging, to coastal breeding and nesting grounds, back to pelagic foraging.
They are found worldwide in tropical and warm temperate ocean waters, and is usually an open ocean inhabitant, commonly found in protected, relatively shallow bays and lagoons and the shallow water between reefs and the shore  
Wicked Diving is lucky enough to experience these turtles in most places we dive. However, the numbers are very low in the Similan Islands so it warrants a special day when we see one. They are spotted in the area around Komodo park and on our expeditions.

Conservation
The olive ridley sea turtle is listed as endangered by the IUCN. Degradation of nesting beaches, ongoing directed harvest, and bycatch in fisheries have all contributed to the decline of the species. The olive ridley may be the most abundant sea turtle on the planet, but some argue that it is also the most exploited.
According to the Marine Turtle Specialist Group (MTSG) of the IUCN, there has been a 50% reduction in population size since the 1960s. Although some nesting populations have increased in the past few years, the overall reduction is greater than the overall increase.
The principal cause of the historical, worldwide decline of the olive ridley sea turtle is long-term collection of eggs and killing of adults on nesting beaches. Because arribadas concentrate females and nests in time and space, they allow for mass slaughters of adult females for their meat and skin, as well as the removal of an excessive number of eggs. These threats continue in some areas of the world today, compromising efforts to recover this species.
Additionally, incidental captures in fishing gear, primarily in longlines, but also in trawls, gill nets, purse seines, and hook and line, frequently snag and drown these turtles and is therefore a serious ongoing source of mortality that adversely affects the species’ recovery.
Though the olive ridley is widely considered the most abundant of the marine turtles, by all estimates, it is in trouble. Rough estimates put the worldwide population of nesting females at about 800,000.
Olive ridley sea turtles are protected by various international treaties and agreements as well as national laws. Many governments have protections for olive ridleys, but still, eggs are taken and nesting females are slaughtered.
This species is also threatened by human impact. Pesticides, heavy metals and PCBs have been detected in turtles and eggs, but their effect is currently unknown. Oil spills cause respiratory, skin, blood and salt gland problems. Marine debris such as plastic bags, plastic and styrofoam, tar, balloons and plastic pellets have been discovered in dead olive ridley stomachs. Consumption of synthetic materials interferes with metabolism and harms the animal through absorption of toxic byproducts. Marine recreation, boating, and ship traffic also threatens this species due to propeller and collision injuries.

Eating olive ridley sea turtles and their eggs, anywhere, can cause severe illness and even death, especially to children. The flesh has been found to contain chelonitoxin which may cause a number of symptoms including nausea, vomiting, diarrhea, burning sensation of lips, tongue and mouth, chest tightness, difficulty swallowing, hypersalivation, skin rash, coma and even death.

The indian ocean walkman (Inimicus didactylus) also known as the Demon Stinger fish, Scorpion fish, Devil Stinger fish, Bearded Ghoul is a member of the Inimicus genus of venomous fishes, closely related to the true stonefishes.
It is irregularly surfaced with spines and a knobby appearance. The fish has venomous spines to ward off enemies.

General Description
Adults can attain a body length of up to 26 centimeters in length. The body color is red or sandy yellow with light blotches, and very similar to that of the surrounding sandy or coral seabed in which they are found. This coloration acts as a camouflage which renders them extremely difficult to detect in their natural habitat. The skin is without scales except along the lateral line, and is covered with venomous spines and wart-like glands which give it a knobby appearance. The head is flattened, depressed and concave. The eyes, mouth and nostrils project upwards and outwards from the dorsal aspect of the head. Sexual dimorphism is not believed to occur in this species.
The species has a depressed head that is strongly concave on the dorsal side. The head is also covered with flaps of skin and raised ridges, and tentacles are present on the head, trunk, and fins. Its mouth points up almost vertically, and its eyes protrude visibly outwards. A raised knob at the end of its snout gives it the appearance of having an upturned nose.
The indian Ocean walkman has a dorsal fin: composed of 15 to 17 spines and 7 to 9 soft rays. A caudal fin: made up of of 2-4 spines and 4-14 soft rays, with dark bands at basal and subterminal positions. The walkman also has a pelvic fin: which includes one spine and 3-5 soft rays and a pectoral fin: comprised of 10-12 rays. The two most caudal rays of each pectoral fin are detached from the rest of the fin, and angled downwards.
The indian ocean walkman is nocturnal and typically lies partially buried on the sea floor or on a coral head during the day, covering itself with sand and other debris to further camouflage itself.
Due to the fact that this species lives a fairly sedentary life, mostly buried in sand it will often become riddled with parasites, algae and crustaceans due to the amount of time spent motionless waiting for prey. Fortunately for the indian oceanic walkman this isn’t much of a problem as it has the ability to shed its outer layer, effectively getting rid of any unwanted passengers.
When disturbed by a diver or a potential predator, the indian ocean walkman fans out its brilliantly colored pectoral and caudal fins as a warning. Once dug in, it is very reluctant to leave its hiding place. When it does move, it displays an unusual way of moving, it crawls slowly along the seabed, employing the four lower rays (two on each side) of its pectoral fins as legs.
When disturbed they raise the spines along their backs and will usually move off out of harms way, however, if cornered they are able to charge at considerable speed.
The indian ocean walkman is highly dangerous and poisonous with venomous spines along its back.


Eating
They feed nocturnally on fish and invertebrates including crustaceans and cephalopods.Indian ocean walkman fish are masters of camouflage, enabling them to lie in wait for their victims to come close, before lunging forward and inhaling their prey with their large mouths. The indian walkman fish have massive mouths and are able to swallow prey that are over half the size of the walkman itself.

Reproduction
The indian oceanic walkman is oviparous, like most other fish species with fertilization taking place inside the body, followed by the female laying her eggs. The eggs are laid in clear or greenish, gelatinous walls of hollow pear-shaped sacks, which float near the surface. The eggs hatch within 5 days. When larvae hatch, they come equipped with fully developed eyes, range in length from 1.5 to 2.3 mm, and have large yolk sacs. As the larvae develop further, they take on the characteristics of two general morphs: preflexion and postflexion. The former is more elongated and slender than the latter with larger development of the pectoral fins.
The breeding season for indian oceanic walkmans is usually in the late spring or early summer.
When it’s time to spawn, some walkmans will travel up to 220 miles to meet their mate. There, they gather on the ocean floor during the day and raise to the surface at night to spawn

Where to Find the Indian Ocean Walkman
The species is usually found in sandy areas and seagrass beds and are mostly solitary creatures, being found in pairs only in the mating season. As the walkmans are masters of camouflage you will find that their habitat varies from fish to fish as no matter the habitat you can be sure indian oceanic walkman fish have adapted to it.
Indian oceanic walkmans usually inhabit shallow waters, but can be also found up to depths of 2194 metres.
Wicked Diving encounters these occasionally in Thailand. However, they are quite common on our muck dives in Komodo.

Conservation
Little is known about the abundance of this species, but it is not generally considered in need of special conservation efforts.
Because of its small size, this species is not fished commercially; however, despite the fact that these fishes are highly venomous, they are collected occasionally for the aquarium trade, where they are sold as “popeyed sea goblins.”

Due to the fact that these prehistoric looking fish are masters of disguise, you will be very fortunate to see one on a dive. Always be careful when sitting down on large sandy areas as an indian oceanic walkman may well be buried in the sand. Also avoid touching any area of hard substrate, the walkman can disguise itself so well that you may think you are touching a rock and inadvertently touch the fish’s venomous spines.

Spinner dolphins (Stenella longirostris) derive their name from a habit of leaping from the water and warping their bodies into graceful curves, or spinning lengthwise before splashing back. The motives for this behavior are not known but such actions are often in themselves enough to distinguish this species.
Common names for the geographic varieties of Stenella longirostris include: the Costa Rican, Eastern, Whitebelly, and Hawaiian or Gray’s dolphins. A dwarfed form of this species is found in the Gulf of Thailand.

General Description
Like other dolphins of the genus Stenella, spinner dolphins are relatively small, reaching lengths of up to 2 metres and weighing approximately 59-77 kilograms at maturity. They have long, slender snouts or beaks that are black above and white below.
Coloration is dark gray dorsally fading to lighter gray on the sides and the belly is white. A dark stripe extends from the flipper to the eye.
Spinner dolphins’ pectoral flippers are used to steer them through the water. They also use them to stroke one another, increasing and affirming social bonds. Dolphin “friends” may swim along, touching flippers and stroking each other. Dolphins that appear to be closely bonded may swim along in synchrony, twisting, turning and swimming in perfect harmony together.
The spinner dolphin can leap into the air and make as many as seven complete spins before diving back into the ocean again, they usually perform a series of spins, each spin tending to be made with less energy, finally finishing up with an emphatic side slap. The power of the spin comes from the tremendous acceleration under the water and the torque of the tail just as the dolphin breaks the surface. The aftermath of the spin — the sound of the slap, the splash on the surface, and the dense bubble cloud underwater, which even distant dolphins can pick up through their echolocation may be the real purpose of the spin.
Spinner dolphins maximize the effect of this splash by twisting around to land in a belly-flop, or back-flop. Spins are most frequently performed while the school is spread out across the water.
The most common cause of spinning is assumed to be in order to rid the spinner dolphin of parasites, such as remora fish.
Spinning may also serve as a courtship display or to eject water from the upper respiratory tract, reset the organs of balance, help mix fluid in the gut and venous reservoirs, or simply be for fun. It might also be important to maintain the spinner’s thermal budget, since the dolphins’ core and subcutaneous temperature are higher when the spinner dolphins are spinning. In order to live most of their lives underwater, spinner dolphins are conscious breathers: they think about when to breathe (probably as much as we think about walking). Therefore, in order to breathe, they have to be conscious. Dolphins sleep by isolating one side of the brain first to sleep then switching to the other side after a few hours. In this way, the animal is never completely unconscious, but still gets the rest it needs. This practice also prevents the dolphins from losing body heat and getting too cold.
Spinner dolphins can be very noisy under and above the water. Echolocation enables dolphins to track objects in dark water or water with poor visibility in order to “see” much further than their eyes will allow. Their complex array of whistles are a means for the dolphins to communicate with one another. The spinners also identify themselves with sound they make whilst trailing bubbles from their blowholes. These sounds are known as signature whistles.

Eating
Spinner dolphins feed at night on mesopelagic fish, shrimp and squid that are found about 650-1,000 feet below the surface of the water. The mesopelagic boundary layer stays in deep waters in the ocean during the day. At night they move up in the water column (vertical migration), and inshore (horizontal migration). Dolphins follow these diel migrations of their prey in order to maximize foraging efficiency.

Reproduction
Adult females give birth to a single calf at two year intervals. Parturition usually occurs in early summer but can occur in any season.
Spinner dolphins carry their young inside their womb and gestation lasts as long as 10 months. The baby emerges tail first, and will suckle from its mother for up to 2 years.
Calves are usually about 75 cm long at birth and can be seen swimming near their mothers for about a week before they swim nearer to her dorsal fin. This is called echelon swimming. Other features of a newborn spinner dolphin are fetal folds; wrinkles along their sides where they were curled up in the womb, and floppy dorsal fins. The dorsal fin, made of cartilage, takes a few days following birth to become hard and rigid. The softness allows it to fold over the calf’s back during birth.
Multiple males may mate with one female in short, consecutive intervals. Calving intervals for males average three years. Maturity occurs at around seven and maximum longevity is twenty years.

Where To Find Spinner Dolphins
Spinner dolphins often associate with spotted dolphins, common dolphins and small to medium sized whales (e.g. pilot whales)
They usually occur in groups of 30 to several hundred but may number into the thousands
In most places, spinner dolphins are found in the deep ocean where they likely track prey. They tend to rest in bays and protected areas during the day and then fuse into larger groups to feed in deeper water on fish and squid at night.
Spinner Dolphins can be found in all tropical and subtropical oceans around inshore waters, islands, banks or shallow coral reefs.
Wicked Diving sees Spinners on many of our expeditions in more remote places and open waters. We have seen them a few times a year in Thailand and once a month or so on our Komodo Liveaboard trips.

Conservation
Spinner dolphins are classified as Lower Risk, however, due to the as yet unexplained association between large yellowfin tuna and schooling dolphins, fisheries have been known to use spinner dolphins in order to track tuna. As a result spinners often become trapped in the nets and drown. Stress from being pursued by the fisheries has also been documented as a very serious threat to dolphins. Currently, fishing methods for tuna imported under the Dolphin Safe Programme do not allow fishing practices, such as setting on dolphins.
Interactions with tourists is also a growing threat to the spinner dolphin population; because the species is active at night, daytime interactions with tourists inhibit necessary rest and sleep time.

As a result Environmentalists and tour operators are at odds as to wether you should dive with the spinner dolphin.
The 1972 Marine Mammal Protection Act prohibits any “taking” of marine mammals, i.e., to “harass, hunt, capture, or kill.” As a “Level B harassment” which was later defined in the act as “any act of pursuit, torment, or annoyance which . . . has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns.”
While the research is ongoing, some experts believe that when humans come to the spinners’ resting grounds, they could change the dolphins’ behavior and perhaps endanger them. The spinners go to those areas “for a purpose, and that’s because they need to rest,”
If the dolphins don’t get adequate downtime, that could make it more difficult for them to fish and to avoid predators at night.
There are some guidelines, in place to protect the spinner dolphin however, many tour operators simply aren’t adhering to them, and the majority of tourists are completely unaware of them.

On a spinner dolphin encounter, the usual procedure is to have snorkelers, swimmers, divers assume a passive float position in a safe, non-intrusive manner, other guidelines request that if swimming, snorkeling or diving with spinners that you remain at least 45 metres from the dolphin and that you limit your time observing to a maximum of 30 minutes. Always remember that spinner dolphins should not be encircled or trapped between boats or the shore.
If approached by a spinner dolphin while on a boat, put the engine in neutral and allow the animal to pass. Boat movement should be from the rear of the animal.

It is up to your discretion if you want to have an encounter with these playful creatures. It is not yet illegal to swim, snorkel or dive with spinner dolphins however various environmental groups are currently working on legislation to make it so. Therefore, before you jump into the water examine both your conscience and the local laws to ensure that you are making the right decision.

The ornate ghost pipefish (Solenostomus paradoxus) occasionally known as the harlequin ghost pipefish, is a pipefish of the family Solenostomidae frequently found along reef edges prone to strong currents.
The ornate ghost pipefish is one of the hardest fish to spot in the ocean.  First of all they are relatively small, only growing to about 12 centimetres in maximum length. This combined with the fact that their bodies look more like coral or seaweed than an actual saltwater fish, makes them a master of camouflage!

General Description
The ornate ghost pipefish can be recognised by its distinctive body form with slender appendages on the body and fins. It has deeply incised membranes in the dorsal, caudal and ventral fins.
Its colour varies from almost totally black to semi-transparent with red, yellow, and white scribbling, spots and blotches and they can reach a maximum length of 12 centimetres.
These pipefish are different to seahorses in several ways. The head is held at an angle to the body, but not at such a large angle as that of the seahorse. One also finds that they have two dorsal fins whereas a seahorse only has one. In addition, the ghost pipefishes do not have a pouch in which the young are reared, instead the female looks after the eggs in a pouch formed by her modified ventral fins. These fins are greatly expanded and united with the abdomen along the upper margin and together below for a brood pouch.
The ornate ghost pipe fish has the elongated snout and laterally compressed body that is typical of all syngnathoid fishes. More specific to the Solenostomid’s is a dermal skeleton composed of plates, a head region that represents over a third of the total body length and the presence of pelvic fins, 2 separate dorsal fins, an anal fin and a large ventral fin.
The females are larger than the males with an average length of 130 mm; males, on average, are 37% smaller.
These spend a lot of time floating upside down, mouth pointed downwards and virtually motionless.
During the breeding season, a murky, muddy bottom or a coral reef is the habitat of choice. Here they change not only their colour, but also their shape in order to camouflage themselves even better.

Eating:
These little treasures eat tiny crustaceans, sucked inside through their long snout.
They feed mostly on mysids but also target small benthic shrimps

Reproduction
This is an external skin-brooding species. Embryos are enclosed in an envelope and attached to special epidermal cells called cotylephores. These cells occur only on the inside surface of the pelvic fins of females (the brooders in this species). The pelvic fins of females are expanded and connect to the body and to each other in order to form a brood pouch (similar to that of a kangaroo).
Females carry eggs in this pouch during the incubation period. This method allows the female to move her young to a site that is better for survival and also limits the risk of exposure to predators during the brood’s developmental stage.
Life starts as a larvae adrift on the currents of the oceans. Maturity is gradually reached during this stage, before settling on the seabed.
At first, the fish will be transparent until it makes its way to the coral reef to reproduce. Here it will take on shape and colour to maximise its camouflage.
They will take a mate and pair off, a union that can often be observed for days on end. Once fertilized, the female will carry around up to 350 eggs in her brooding pouch. These eggs will eventually be set adrift, restarting the cycle of life once more.

Where to Find Ornate Ghost Pipefish
They usually solitary, but has also been observed in pairs or very small groups.
The species is found in protected coastal waters, at depths between 3 metres and 25 metres especially near coral and rocky dropoffs. Usually they will be found living within crinoids, feather stars, gorgonian fans and branching black coral bushes. Here they live very well camouflaged by their complex colour patterns and body shape.
Because they are relatively weak swimmers, rapidly fanning their little fins for propulsion, they tend to stay within very small territories. Even though the fins provide accurate navigation and precise positioning of their bodies, their range is extremely limited.

With a keen eye they are found on many dive sites of the Similan Islands. In Komodo they are also found by the passionate diver – but due to currents, they are not found on all sites.

Conservation
Coral bleaching, pollution and destructive fishing methods all impact on the habitat and the life cycle of the ornate ghost pipefish, the aquarium trade also negatively affect their numbers in the wild.

Colourful and distinctive, small and delicate, motionless and elongate, they are so small, (about the size of a finger) and blend in so well with their surroundings that they are near-impossible to find, divers who are willing to hover and stare at feather stars and gorgonians for long periods of time may just be rewarded for their patience!

Robust Ghost Pipefish

 

 Robust ghost pipefish also better known as False Pipefish, Tube mouth Fish, Blue-Finned Ghost Pipefish, Squaretail Ghost Pipefish and Seagrass Ghost Pipefish are in fact not members of the Pipefish family, but are closely related to the Pipefish and Sea Horse family, which is perhaps why the Robust Ghost Pipefish while having the long tube-like snout taking up 1/3 of its size is similar to the pipefish, and its body covered with external plates makes its appearance and size more like a seahorse.

With their incredible ability to mimic their surroundings and their tiny size, it is not surprising that these spectacular critters are seldom spotted by divers.  Robust ghost pipefishes are masters of disguise. In fact they may have some of the best disguises in the sea but when viewed, they are one of the oceans most beautiful creatures!

 

 General Description

Robust ghost pipefish are closely related to Seahorses, but unlike Seahorses, male  robust ghost pipefish do not have a pouch in which the young are reared. Instead the female has the pouch and has to look after the eggs.

 Robust ghost pipefishes are also different to seahorses in several other ways. A  robust ghost pipefish’s head is held at an angle to the body, but not at such a large angle as that of the seahorse.  Robust ghost pipefishes have two dorsal fins whereas a seahorse only has one.

Colour varies from place to place blending in with surroundings ranging from Green to brown.

In certain habitats, like among rocks and macroalgae, they assume a blotched color pattern.

The  robust ghost pipefish mimics the appearance of rotting sea grass or seaweed making it very difficult to spot. The species grows up to 15cms, live at depths of 5-20m and are also characterised by their hard body plates and tubular snouts, similar to the closely related seahorses.

Robust ghost pipefish use their incredible camouflage as their best line of defence. Their hard body plates also make them difficult to swallow for many smaller predators.

 Female  robust ghost pipefish can be up to twice as large as males and groups of smaller males are often seen accompanying a larger female as she produces and incubates the eggs.

It is easily distinguished from other members of the genus by the short caudal peduncle, and a highly distinctive deep snout. The snout is especially wide in larger males. Its body is also sometimes covered with small filaments. The caudal fin of this species is lanceolate, with the membranes between the rays being slightly incised. The  robust ghost pipefish will usually hang vertically, with its head directed towards the sea floor, but will sometimes adopt a horizontal orientation to the substrate when it swims.

It can easily be identified by a uniform colouration of beige, brown, black, green or very rarely bright red.  It has no filaments or hairs and no distinctive markings over the body.  It mimics seagrasses with uncanny ability and also sways with surge or current in the same way as an inanimate leaf.

 

 

 Eating

The species feeds on plankton and small crustaceans, such as shrimp, mysids (opossum shrimps) and benthic creatures which it sucks off the seafloor.  Robust ghost pipefish often hang upside down while feeding and the unassuming prey is sucked up through the specially adapted snout.

 

Reproduction

Unlike seahorses, male  robust ghost pipefishes do not have a pouch in which the young are reared, instead a female ghost pipefish looks after the eggs in a pouch formed by her modified ventral fins. These fins are greatly expanded and united with the abdomen along the upper margin and below to form a brood pouch (almost like a kangaroo!).

After incubation, the eggs are released into the water column and are planktonic, travelling with the currents until they find a suitable reef to inhabit.

The eggs spend a relatively long amount of time floating around in the ocean as plankton, reaching almost adult length before they finally settle onto the reef. This means that they have a wide geographic range since they can travel long distances after they are born.  The  robust ghost pipefish are generally found living in male and female pairs.

 

 

Where to Find Robust Ghost Pipefish

The  robust ghost pipefish tend to make their homes in current swept areas, close to a steady stream of food. Always found in pairs or family groups floating with head down mimicking seagrass on seagrass beds at the edge of reefs. When disturbed it will move into the vegetation.

hovering close to the substrate or some sort of submerged object offering a measure of protection from open-water predators: they usually seem to prefer silty, open substrates in coastal calm and shallow waters, often being found on coarse sand and broken coral rubble, but in fact it is not uncommon at all finding them in rich coral reef areas too.

 

We encounter these in both Thailand and Komodo. However, in Thailand they tend to be very well camoflauged in detrius. In Komodo we more easily find them in the shallows.

 

Conservation

Robust ghost pipefish  are not considered to be great to eat and unlike their cousins the seahorses are not prized for their medicinal powers, so they are rarely fished. They are most at threat from the aquarium trade and loss of habitat due to the overall decline of the worlds reefs.

 

The robust ghost pipefish  is one of those sea creatures that divers simply love , mainly due to the fact that these tiny creatures are so difficult to spot, blending in so well with their surroundings, that often the only way to see  robust ghost pipefish is to dive with an experienced dive master who knows where they live on the reef. The second reason for these creatures being so popular with divers is that they are simply stunning and unusual creatures to look at, as they hover motionlessly upside down looking like an extension of the coral behind it.

 

 The  eagle rays are a group of cartilaginous fish that are part of the family of  Myliobatidae. Eagle rays  are basically large species of rays that unlike many ray species, tend to live in the open ocean rather than on the bottom of the sea.

The Genus name of this type of fish is  Aetobatus  which is a word derived from the Greek meaning eagle (aetos) and ray (batis).

 

General Description

The  eagle ray has a very long tail and a well defined body that ranges from 48 centimetres to 9 meters in length.  They have inky blue bodies and a long tail that can reach up to 5 meters in length. The eagle ray also has a very angular disc and a long broad snout rounded like a duck’s bill, with a “v” shaped flap.

It has a pectoral disc with sharply curved, angular corners, and no caudal fin; their jaws contain a single row of flat, chevron-shaped teeth. Each tooth is a crescent-shaped plate joined into a band.

The  eagle ray swims by moving its two wings vertically – sometimes they break the surface of the sea and give the impression of two sharks traveling together. The  eagle ray can also jump out and across the surface of the water.

 

Eating

Eagle rays feed on mollusks and crustaceans such as clams, shrimp, oysters, octopus, squids, sea urchins as well as bony fishes. They crush the shells with their flattened and very strong teeth and are very fast swimmers, which allows them to hunt efficiently.  This type of ray is very well-adapted with its shovel shaped snout for searching for food in the mud for benthic invertebrates. When they find their prey, the  eagle ray  crushes it with its teeth and uses the papillae in its mouth to separate the shells from the flesh.

 

Reproduction

Eagle rays are ovoviviparous (aplacental viviparity) specimens, meaning that their eggs develop inside the body and hatch within the mother, feeding initially on yolk, then receiving additional nourishment from the mother by indirect absorption of uterine fluid enriched with mucus, fat or protein through specialized structures. They tend to give birth to up to six young at a time, whose width at birth ranges from 17-35 centimetres.

Their mating behavior consists of many male  eagle rays pursuing a female. The male chases the female in mid water, then nibbles on her dorsal surface. The female stops swimming to begin copulation. The male bites the female on a pectoral fin and bends one clasper forward, then attempts an abdomen to abdomen copulation with either clasper, usually mid-water. Copulation lasted for 20 seconds to 1 minute, this makes it possible for females to mate with up to four males over a short period of time.

 

Where to Find The Eagle Ray

The  eagle ray tends to inhabit warm, tropical waters, however they have occasionally been seen to enter estuaries. They swim close to the surface, occasionally leaping out of the water, or close to the bottom.

The eagle ray is commonly spotted swimming in bays and around coral reefs.  It spends most of its time, however, swimming in schools in the open water.  Eagle rays swim in big groups just below the surface where they travel very long distances, but they usually return to their original location where they interact with other  eagle rays.

 

Eagle Rays are found on many of the dives sites of Komodo and surrounding areas. They are also found in Thailand where our Similan Liveaboard operates

 

Conservation

The  eagle ray is considered as a “Near Threatened” species by the World Conservation Union (IUCN). However, the eagle ray is considered of minor commercial importance since the poor quality of the flesh makes it a difficult fish to eat. While  eagle rays are often captured by humans, this is usually for aquarium purposes.

A taxon is Near Threatened when it has been evaluated against the criteria but does not qualify for Critically Endangered, Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future.

 

The  eagle ray is generally considered to be a shy species wary of scuba divers and difficult to approach because they tend to swim away. Therefore they represent no real threat to scuba divers as long as they are left alone to enjoy their natural habitat without any difficulties.

Nevertheless, they are considered a potentially dangerous species due to their venomous tail spines that can inflict serious wounds if the human gets too close.

Dugongs

 

The  dugong  is a large marine mammal, sometimes refered to as a “Seacow”. They are considered to be the inspiration behind the myth of Mermaids.  Dugongs are large grey mammals which spend their entire lives in the sea. Though Acquatic they breathe air through their lungs and give birth to live babies rather than lay eggs like fish.

 

General Description

The  dugong  can reach up to 3 metres in length and weigh almost 500 kilograms. They have a thick layer of fat giving them a distinctly rotund posture, small paddle-like fins positioned far forward on the body and a broad, flattened, powerful tail that resembles the tail of whale.

The  dugong has thick, smooth skin that is a pale cream colour at birth, but darkens dorsally and laterally to brownish-to-dark-grey with age. The colour can also change due to the growth of algae on the skin. The skin of a  dugong appears smooth, but a really close view reveals a rough surface covered in pits from which grow short, thick hairs.  dugongs have 2 nostrils near the top of their heads on a “fleshy lip”, which can curl up to make breathing easier on the surface. Its snout is sharply downturned, an adaptation for grazing and uprooting benthic seagrasses.

Dugongs  can dive for up to six minutes on the same breath and rest on their tail to breathe with their heads held above the water.

The  dugong can dive to a maximum depth of 39 metres, although the majority spend their lives at a depth of 10 metres.

Communication between  dugongs comprises of a series of whistles, chirps barks and other sounds that echo underwater.

Due to their poor eyesight,  dugongs often use smell to locate edible plants. They also have a strong tactile sense, and feel their surroundings with their long sensitive bristles

Dugong  are slow-moving and have little protection against predators. They have few natural predators, although animals such as Crocodiles, Killer Whales, and Sharks pose a threat to the young, who tend to hide behind their mothers when in danger.

Dugong  males have ivory tusks used for fighting during male-male rivalry as well for uprooting seagrasses.

 

Eating

Dugongs are sometimes called “Sea Cows”, because they graze on seagrasses. These marine plants look like grass growing on a sandy sea floor in shallow, warm water.Dugongs eat large amounts of seagrass, leaving behind feeding trails of bare sand and uprooted seagrass, they have also been known to consume algae and invertebrates such as jellyfish sea squirts and shellfish when a supply of seagrass has been scarce.

 

Reproduction

Female  dugongs  give birth underwater to a single calf every three to seven years. They give birth in extremely shallow waters enabling the baby  dugong to swim to the surface to take its first breath. Baby  dugongs are about 100 to 120 centimetres long and weigh 20 to 30 kilograms at birth. The calf stays with its mother, drinking milk from her teats and following close by until 18 to 24 months of age.

Dugongs reach adult size between 9 and 17 years of age, and reach sexual maturity between the ages of 8 to 18 and have a lifespan similar to humans, if left alone.

 

Where to Find  Dugongs

Dugongs swim in warm shallow coastal waters were they find protection from large waves and storms. the largest dugong concentrations typically occurring in wide, shallow, protected areas such as bays, mangrove channels and the lee sides of large inshore islands  dugongs surface only to breathe, and never come onto land.

Although they are social animals, they are usually solitary or found in pairs due to the inability of seagrass beds to support large populations. Gatherings of hundreds of dugongs sometimes happen, Because they are shy, and do not approach humans, little is known aboutdugong behaviour

Dugongs are found in warm coastal waters from the western Pacific Ocean to the eastern coast of Africa

 

Here at Wicked Diving – We find them throughout the Komodo Park and surrounding islands and bays. They are rarely found in the waters of Thailand, though they do exist.

 

Conservation

The  dugong has been hunted for thousands of years for its meat, skin, bones and oil. Despite being legally protected in many countries, the main causes of population decline include hunting, habitat degradation, and fishing-related fatalities. Due to its slow rate of reproduction, and long life span, the  dugong is especially vulnerable to extinction.

 

Melibe

Melibe is a genus of sea slugs, nudibranchs, marine gastropod mollusks in the family Tethydidae. Other common names include “Hooded Nudibranch” and “Transparent Nudibranch”.
Most nudibranchs are carnivores, but their prey is usually comprises of slow-moving animals such as sponges or bryozoans. In contrast, melibe is an active predator which traps fast-moving free-swimming animals such as small crustaceans and amphipods, using its extendable oral hood.

General Description
The melibe is like no other nudibranch or sea slug, Instead of a rasping tongue, it sports a unique oral hood that captures small planktonic animals. The large expandable oral hood, fringed with sensory tentacles, opens and is thrown forward in order to catch food. A single pair of rhinophores on the hood are rounded and earlike. 4-6 pairs of flat paddle shaped cerata run along its dorsum in two rows. A close look may reveal the digestive tract, visible as dark branching lines running down the length of the body.
Melibe and the giant kelp plants they live on have matching colors—yellowish brown to olive green with a translucent body which reaches approximately 15cm upon maturity.
Although they prefer to stay attached to a surface, melibe do swim when dislodged or if they’re approached by a kelp crab, then they close their hood to reduce drag. Most predators avoid the noxious secretions of nudibranchs; but the kelp crab is an exception. The noxious secretions of the melibe are said to exude a fruity smell.
The life span of the melibe is approximately 1 year, they die shortly after laying their eggs.

Eating
To feed, a melibe firmly attaches itself to a kelp blade and then sweeps its raised hood downward or to the side. When food lands on the lower surface of the hood, themelibe sweeps together the two sides of the hood, and its fringing tentacles lock in the prey. The hood contracts to force the captured food into the melibe’s mouth.
Prey include amphipods, copepods, mysids, other small crustaceans, small mollusks, small jellyfish and ctenophores, larvae of other invertebrates and occasionally small fish.

Reproduction
Melibe are hermaphrodites (they have both male and female sexual organs), and fertilization occurs internally. The animal can lay as many as 30,000 eggs, which are enclosed in a long, gelatinous yellow or cream-colored ribbons which form tight coils or wavy folds.

Where to Find Melibe
The melibe is usually found on eelgrass and other seaweeds near low tide and below, and in kelp forest in deeper water.

While we have yet to encounter one of these in Thailand – we do find encounter them in the sea grasses found near our Komodo Dive center.

Conservation
This unique and amazing animal is neither collected nor hunted, but its existence depends on healthy kelp forests and other seaweed beds. Sludge and other pollutants smother tiny kelp plants during their microscopic stage.