10 The Worlds Most Dangerous Water Animal

Wednesday, August 8, 2012

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10 The Worlds Most Dangerous Water Animal

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10. Moray eels (Muraenidae).

With a maximum length of 11.5 centimetres (4.5 in), the smallest moray is likely the Snyder's moray (Anarchias leucurus), while the longest species, the slender giant moray (Strophidon sathete) reaches up to 4 m (13 ft). The largest in terms of total mass is the giant moray (Gymnothorax javanicus), which reaches 3 m (9.8 ft) in length and 30 kg (66 lb) in weight. The body is generally patterned. In some species, the inside of the mouth is also patterned. Their jaws are wide, framing a protruding snout. Most possess large teeth that are designed to tear flesh or grasp slippery prey items. A relatively small number of species, for example the snowflake moray (Echidna nebulosa) and zebra moray (Gymnomuraena zebra), primarily feed on crustaceans and other hard-shelled animals, and they have blunt, molar-like teeth suitable for crushing. Moray eels' heads are too narrow to create the negative pressure that most fish use to swallow prey. Quite possibly because of this, they have a second set of jaws in their throat called pharyngeal jaws, which also possess teeth. When feeding, morays launch these jaws into the mouth, where they grasp prey and transport it into the throat and digestive system. Moray eels are the only animal that uses pharyngeal jaws to actively capture and restrain prey. Larger morays are capable of seriously wounding humans. Morays 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 in sand-dwelling morays, 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.Morays are carnivorous and feed primarily on other fish, cephalopods, molluscs, and crustaceans. Groupers, barracudas and sea snakes are among their few predators. There is a commercial fishery for several species, but some cause ciguatera fish poisoning.

9. Lion Fish ( Pterois).

Pterois is a genus of venomous marine fish, also known as the lionfish, found mostly in the Indo-Pacific. Pterois is characterized by red, white and black bands, showy pectoral fins and venomous spiky fin rays. Pterois are classified into nine different species, but Pterois radiata, Pterois volitans and Pterois miles are the most commonly studied. Pterois are popular aquarium fish and are readily utilized in the culinary world. In the mid 1990s, the species P. volitans and P. miles were unintentionally introduced into the Atlantic Ocean and have become an invasive species along the East Coast of the United States, the Mesoamerican Barrier Reef System, and the wider Caribbean. They are now also found in the Gulf of Mexico. Lion Fish range in size from 6.2 to 42.4 cm with typical adults measuring 38 cm and weighing an average of 480 g. But some species have enough venom to produce extreme discomfort for over a period of several days. However, "Lion Fish" venom can provide a danger to allergic victims because some victims may experience anaphylaxis which is a serious and often life threatening allergic reaction that requires immediate emergency medical treatment. Severe allergic reactions to "Lion Fish" venom are usually chest pain, severe breathing difficulties, a drop in blood pressure swelling of the tongue, sweating, runny nose, or slurred speech. If left untreated, The reaction may lead to cardiac arrest and then death.

8. Sea Wasp (Chironex fleckeri).

Sea Wasp (Chironex fleckeri),  is a species of Box jellyfish found in coastal waters from northern Australia and New Guinea north to the Philippines and Vietnam. It has been described as "the most lethal jellyfish in the world", with at least 63 known deaths in Australia from 1884 to 1996. Notorious for its sting, C. fleckeri has tentacles up to 3 metres (9.8 ft) long which are covered in thousands upon thousands of cnidocytes which, on contact, release microscopic darts, each delivering an extremely powerful venom. Being stung commonly results in excruciating pain, and if the sting area is significant, an untreated victim may die in as little as three minutes. The amount of venom in one animal is said to be enough to kill 60 adult humans (although most stings are mild). First aid consists of washing the sting area with vinegar, and in no circumstance should alcohol, alcohol-based lotions, or methylated spirits be applied. Cardiopulmonary resuscitation (CPR) may be required. Medical help should be sought as soon as possible after considering these needs.

7. Great White Shark (Carcharodon carcharias).

The great white shark, Carcharodon carcharias, also known as the great white, white pointer, white shark, or white death, is a large lamniform shark found in coastal surface waters in all major oceans. It is known for its size, with the largest individuals known to have approached or exceeded 6 m (20 ft) in length, and 2,268 kg (5,000 lb) in weight. This shark reaches maturity at around 15 years of age and can have a life span of over 30 years. The great white shark is arguably the world's largest known extant macropredatory fish, and is one of the primary predators of marine mammals. It is also known to prey upon a variety of other marine animals, including fish and seabirds. It is the only known surviving species of its genus, Carcharodon, and is ranked first in a list of number of recorded attacks on humans. The IUCN treats the great white shark as vulnerable, while it is included in Appendix II of CITES. Humans, in any case, are not appropriate prey because the shark's digestion is too slow to cope with a human's high ratio of bone to muscle and fat. Accordingly, in most recorded attacks, great whites broke off contact after the first bite. Fatalities are usually caused by blood loss from the initial bite rather than from critical organ loss or from whole consumption. Since 1990 there have been a total of 139 unprovoked great white shark attacks, 29 of them fatal.

6. Sea Snake (Hydrophiinae).

Hydrophiinae, also known as sea snakes, is a group of venomous elapid snakes that inhabit marine environments for most or all of their lives. Though they evolved from terrestrial ancestors, most are extensively adapted to a fully aquatic life and are unable to move on land, except for the genus Laticauda, which retain ancestral characteristics, allowing limited land movement. They are found in warm coastal waters from the Indian Ocean to the Pacific. All have paddle-like tails and many have laterally compressed bodies that give them an eel-like appearance. Unlike fish, they do not have gills and must surface regularly to breathe. They are among the most completely aquatic of all air-breathing vertebrates.[1] Among this group are species with some of the most potent venoms of all snakes. Some have gentle dispositions and bite only when provoked, but others are much more aggressive. Currently, 17 genera are described as sea snakes, comprising 62 species. Like their cousins in the Elapidae family, the majority of hydrophiinae species are highly venomous; however, when bites occur, it is rare for much venom to be injected, so that envenomation symptoms usually seem non-existent or trivial. For example, The Yellow-Bellied Sea Snake (Pelamis Platurus) has a venom more potent than any terrestrial snake species in Costa Rica based on LD50, but despite its abundance in the waters off its western coast, few human fatalities have been reported. Nevertheless, all sea snakes should be handled with great caution. Bites in which envenomation does occur are usually painless and may not even be noticed when contact is made. Teeth may remain in the wound. There is usually little or no swelling, and it is rare for any nearby lymph nodes to be affected. The most important symptoms are rhabdomyolysis (rapid breakdown of skeletal muscle tissue) and paralysis. Early symptoms include headache, a thick-feeling tongue, thirst, sweating, and vomiting. Symptoms that can occur after 30 minutes to several hours post-bite include generalized aching, stiffness, and tenderness of muscles all over the body. Passive stretching of the muscles is also painful, and trismus, which is similar to tetanus, is common. This is followed later on by symptoms typical of other elapid envenomations: a progressive flaccid paralysis, starting with ptosis and paralysis of voluntary muscles. Paralysis of muscles involved in swallowing and respiration can be fatal. After 3–8 hours, myoglobin as a result of muscle breakdown may start to show up in the blood plasma, which can cause the urine to turn a dark reddish, brown, or black color, and eventually lead to acute renal failure. After 6 to 12 hours, severe hyperkalemia, also the result of muscle breakdown, can lead to cardiac arrest.

5. Stonefishes (Synanceia ).

Synanceia is a genus of fish of the family Synanceiidae, the Stonefishes, whose members are venomous, dangerous, and even fatal to humans. It is one of the most venomous fishes in the world currently known. They are found in the coastal regions of Indo-Pacific oceans. Synanceia are primarily marine, though some species are known to live in rivers. Its species have potent neurotoxins secreted from glands at the base of their needle-like dorsal fin spines which stick up when disturbed or threatened. The vernacular name of the species, the stonefish, derives from the stonefish's ability to camouflage itself with a grey and mottled color similar to the color of a stone. Swimmers may not notice them, and may inadvertently step on them, triggering a sting. When the stonefish is disturbed, it may inject an amount of venom proportional to the amount of pressure applied to it. There were 25 cases of the use of antivenom for stonefish reported to Commonwealth Serum Laboratories for a one-year period between July 1989 and June 1990, with most from Queensland and four from the Northern Territory. There were 14 calls to the Queensland Poisons Information System in 2008 regarding stonefish poison.

4. The Blue-Ringed Octopuses (Hapalochlaena).

The blue-ringed octopuses (genus Hapalochlaena) are three (or perhaps four) octopus species that live in tide pools and coral reefs in the Pacific and Indian Oceans, from Japan to Australia (mainly around southern New South Wales and South Australia). They are recognized as one of the world's most venomous marine animals. Despite their small size and relatively docile nature, they can prove a danger to humans. They can be recognized by their characteristic blue and black rings and yellowish skin. When the octopus is agitated, the brown patches darken dramatically, and iridescent blue rings or clumps of rings appear and pulsate within the maculae. Typically 50-60 blue rings cover the dorsal and lateral surfaces of the mantle. They hunt small crabs, hermit crabs, and shrimp, and may bite attackers, including humans, if provoked. The blue-ringed octopus is 12 to 20 cm (5 to 8 inches), but its venom is powerful enough to kill humans. There is no blue-ringed octopus antivenom available. The octopus produces venom that contains tetrodotoxin, 5-hydroxytryptamine, hyaluronidase, tyramine, histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine. The major neurotoxin component of blue-ringed octopus venom was originally known as maculotoxin but was later found to be identical to tetrodotoxin, a neurotoxin which is also found in pufferfish that is 10,000 times more toxic than cyanide. Tetrodotoxin blocks sodium channels, causing motor paralysis and respiratory arrest within minutes of exposure, leading to cardiac arrest due to a lack of oxygen. The toxin is produced by bacteria in the salivary glands of the octopus.

3. Marble Cone Snail (Conus marmoreus).

Conus marmoreus, common name the "marbled cone", is a species of predatory sea snail, a marine gastropod mollusk in the family Conidae, the cone snails, cone shells or cones. This is a species which is believed to feed mostly on marine molluscs including other cone snails. This snail is venomous, like all cone snails. Its venom is highly potent, and one drop can kill more than 20 men. Its venom cause intense pain swelling tingling and numbness, but severe cases it could have muscles paralysis, breathing failure and problem in eye vision. The worst part is, there is no anti-venom for this snail. There is one subspecies: Conus marmoreus bandanus Lamarck. This species occurs in the Indian Ocean along Chagos and Madagascar, in the Bay of Bengal along India; in the western part of the Pacific Ocean to Fiji and the Marshall Islands. The size of an adult shell can vary between 30 mm and 150 mm. In this species, the shell color can range from black with white dots, to orange with white reticulations, so arranged as to expose the white in rounded triangular large spots. The aperture is white or light pink.

2. Puffer Fish (Tetraodontidae).

Tetraodontidae is a family of primarily marine and estuarine fish of the Tetraodontiformes order. The family includes many familiar species, which are variously called pufferfish, puffers, balloonfish, blowfish, bubblefish, globefish, swellfish, toadfish, toadies, honey toads, sugar toads, and sea squab. They are morphologically similar to the closely related porcupinefish, which have large external spines (unlike the thinner, hidden spines of Tetraodontidae, which are only visible when the fish has puffed up). The scientific name refers to the four large teeth, fused into an upper and lower plate, which are used for crushing the shells of crustaceans and mollusks, their natural prey. Pufferfish are generally believed to be the second–most poisonous vertebrates in the world, after the golden poison frog. Certain internal organs, such as liver, and sometimes the skin, are highly toxic to most animals when eaten; nevertheless, the meat of some species is considered a delicacy in Japan (as fugu), Korea (as bok), and China (as hétún) when prepared by chefs who know which part is safe to eat and in what quantity. The Tetraodontidae contain at least 120 species of puffers in 19 genera. They are most diverse in the tropics and relatively uncommon in the temperate zone and completely absent from cold waters. They are typically small to medium in size, although a few species can reach lengths of greater than 100 centimetres (39 in).

1. Candiru Fish.

 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; morays rely on their highly developed sense of smell, lying in wait to ambush prey. Candiru (English and Portuguese) or candirú (Spanish), also known as cañero, toothpick fish, or vampire fish, are a number of genera of parasitic freshwater catfish in the family Trichomycteridae; all are native to the Amazon River. Although some candiru species have been known to grow to a size of 40 centimetres (16 in) in length, others are considerably smaller. These smaller species are known for an alleged tendency to invade and parasitise the human urethra; however, despite ethnological reports dating back to the late 19th century, the first documented case of the removal of a candiru from a human urethra did not occur until 1997, and even that
 incident has remained a matter of controversy. The definition of candiru differs between authors. The word has been used to refer to only Vandellia cirrhosa, the entire genus Vandellia, the subfamily Vandelliinae, or even the two subfamilies Vandelliinae and Stegophilinae. Candirus are small fish. Adults can grow to around 40 centimetres (16 in) with a rather small head and a belly that can appear distended, especially after a large blood meal. The body is translucent, making it quite difficult to spot in the turbid waters of its home. There are short sensory barbels around the head, together with short, backward pointing spines on the gill covers. According to Samad, the patient claimed "the fish had darted out of the water, up the urine stream, and into his urethra." While this is the most popularly known legendary trait of the candiru, according to Spotte it has been known conclusively to be a myth for more than a century, as it is impossible due to simple fluid physics.   The documentation and specimen provided indicate a fish that was 133.5 mm in length and had a head with a diameter of 11.5 mm. This would have required significant force to pry the urethra open to this extent. The candiru has no appendages or other apparatus that would have been necessary to accomplish this, and if it were leaping out of the water as the patient claimed, it would not have had sufficient leverage to force its way inside. Samad's paper claims the fish must have been attracted by the urine. This belief about the fish has been around for centuries, but was discredited in 2001. While this was merely speculation on Samad's part based on the
 prevailing scientific knowledge at the time, it somewhat erodes the patient's story by eliminating the motivation for the fish to have attacked him in the first place Samad claimed the fish had "chewed" its way through the ventral wall of the urethra into the patient's scrotum. Spotte notes that the candiru does not possess the right teeth or strong enough dentition to have been capable of this. Samad claimed he had to snip the candiru's grasping spikes off in order to extract it, yet the specimen provided had all its spikes intact. The cystoscopy video depicts traveling into to a tubular space (presumed to be the patient's urethra) containing the fish's carcass and then pulling it out backwards through the urethral opening, something that would have been almost impossible with the fish's spikes intact. This vicious fish introduces itself into the most intimate parts of the human body, maintaining itself there by poisonous barbs while it feeds on the soft membranes. Traditional treatment is with two plants, Xagua (Genipa americana) and apple Buitach inserted into the affected area. Both of these plants will kill and dissolve the fish. More often, infection causes shock and death of the victim before candirú can be taken.

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Source. Wikipedia

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