Beautiful but Deadly: Marine Life's Dark Side

A walk on the beach in an island somewhere off Asia, Australia or anywhere in the Caribbean is a promising adventure, dipping yourself underwater with the SCUBA gear would be twice the fun. However so, here are a few things to consider before you touch anything underwater which maybe of interest to you.

The Crown-of-Thorns Starfish 

The The Crown-of-Thorns Starfish can be found in tropical coral reefs in the Red Sea, Indian Ocean and the Pacific Ocean and particularly in the Philippines. They are solitary animals which tend to feed alone maintaining distance between themselves and other members of their species. As they prey upon coral polyps they became notorious in the destruction of coral reefs with an adult capable of cleaning up to 6 square meters of living reef for a year. One starfish of this kind can grow from the size of a grain of sand to the size of a dinner plate and is capable of limb regeneration and can regrow to full size of a severed limb. The sharp spines on the side of the starfish’s limbs resemble thorns and are noted for sharpness which could penetrate standard wetsuits and other clothing.

Scorpion Fish

Scorpaenidae, a family of fishes referred to as the scorpion fish are mostly among the world’s most venomous species. As the name implies they have the type of sting coming from their sharp spines coated with venomous mucus. This family comprise a large number of members mostly over a hundred and could be found in tropical and temperate seas, Indo-Pacific and warm shorelines of the United States. Extreme care must also be considered since with its ornamental appearance, they are often sold as aquarium pets. General characteristics of fishes under this category are compressed body, ridges and/or spines on the head, one or two spines on the operculum, and three to five spines on the preopercle. The spines of the dorsal, anal, and pelvic fins all have venom glands at their bases. A scorpion fish sting causes intense pain and swelling at the portion of the sting. Swelling can spread to affect an entire arm or leg within minutes.  

Stonefish

The Stonefish is a master of camouflage, which makes it even more dangerous, as people often get to close without realizing it. They can be found on the sea bottom and around coral reefs, disguised as rocks. Synanceia is a genus of fish of the family Synanceiidae, commonly referred to as Stonefishes, whose members are  dangerous  or fatal  to humans.  They are  found  in  the coastal regions  of  Indo-Pacific oceans.  They 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. They are the most poisonous fish in the world. With 13 spikes on its back, all filled with extremely potent, protein-based venom. Depending on how deep the sting is, this venom can kill a person in a few hours unless he receives medical attention. 

Blue-Ringed Octopus

The Blue-Ringed Octopus ( Genus-Hapalochlaena) refers to a type of octopus which include 4 species. These octopuses thrive in the salty waters of the Pacific Ocean, Japan and Australia. Characterized by relatively small size and noted for being docile,  extreme care must however be exercised as they are recognized as one of the world’s most venomous animals easily identified by their characteristic blue and black rings and yellowish skin. An individual blue-ringed octopus will normally use its dermal chromatophore cells to camouflage itself until provoked, at which point it quickly changes color, becoming bright yellow with blue rings or lines. It hunts small crabs, shrimps, and may bite attackers, including humans, if provoked or stepped on. It usually grows about the size of a golf ball but its venom is powerful enough to kill humans. As of the present there is no Blue-Ringed Octopus antivenom available. When injected, its venom may contain,  tetrodotoxin, 5-hydroxytryp-tamine, 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 and cone snails. Tetrodo- toxin blocks sodium  channels, causing motor paralysis and sometimes respiratory arrest leading to cardiac arrest due to a lack of oxygen. The toxin is created by bacteria in the salivary glands of the octopus. Chances of survival would be assured if artifical respiration is started before the sign of cyanosis and hypotension aggravates. Victims who live through the first 24 hours generally gain complete recovery.

Sea Krait

Out of 17 genera comprised by 16 species, sea snakes may look less annihilating but the majority are considered poisonous. Unlike fish sea snakes don’t have gills and as such must surface regularly to breathe. Yellow-lipped sea kraits are found mostly in coral atolls and rocky islets where it usually gather in numbers to breed. Growing as long as 1.5 m and weighing an average of 2 kg, these creatures stay on the water to hunt and return to land to digest, breed and shed their skins. They are venomous but generally non aggressive when in contact with humans. But if you must consider, sea snakes venom are known to be 10 times as strong as a rattlesnake’s venom so I wouldn’t take my chance.

Cone Snail

There are 500 different species of cone snails and they are found in tropical and warm seas like Australia, or scattered on oceans worldwide and some thriving in temperate environments such as the  Cape coast of South Africa or the cool waters of Southern California. Cone snails are medium sized to large. Their shells are shaped roughly like an ice cream cone with the narrow end of the cone shell as its anterior and the wide end shows the usually very low spire of the gastropod shell. These snails hunt and immobilize their prey by using a modified radular tooth along with a poison gland containing neurotoxins which is launched out of its mouth in a harpoon-like action Symptoms of a more serious cone snail sting include intense pain, swelling, numbness and tingling. Symptoms can start immediately or can be delayed in onset for days. Severe cases involve muscle paralysis, changes in vision and respiratory failure that can lead to death. There is no antivenom, and treatment involves providing life support until the venom is metabolised by the victim. 

Sea Wasps

Sea Wasps or the Boxed Jellyfish as it is popularly called belong to a class of Cubozoa, named for their cube-shaped medusae. Cubozoans are categorized separately from other types of jellyfish and are considered more complex than Scyphozoans.Box jellies can be found in Australia, the Philippines, Hawaii, Vietnam, and many other tropical areas. The Chironex fleckeri and the Carukia barnesi (Irukandji) species are amongst the most venomous. Human deaths attributed to encounters with these creatures has caused at least 5,568 lives eversince 1954.The “bell” of this box jelly can get as big as a basketball with up to 60 tentacles hanging down as long as 15 feet, which is pretty good sized jelly.Sea Wasps, or box jellies, are not aggressive but are pretty fast swimmers (up to 5mph), dangling their long tentacles in the surf behind them until something, usually a fish, gets caught in their practically invisible tentacles. That’s where all their nematocysts (stinging capsules contained within cells called cnidocytes located along the tentacles) are located. If swimming at a beach where box jellyfish are known to be present, a bottle of vinegar is an extremely useful addition to the first aid kit. Acetic acid, found in vinegar, disables the box jelly’s nematocysts that have not yet discharged into the bloodstream (though it will not alleviate the pain).Turns out, something as thin and flimsy as women’s nylon pantyhose worn over the skin will prevent the jellies from stinging. Aussies have known about this trick for years. 

Xanthid Crab

Crabs belonging to the family Xanthidae includes the colorful egg crabs, reef crabs and spoon-pincer crab. They are commonly found among every shores especially in coral rubble areas. These crabs are generally non venomous but highly poisonous when ingested. So if you think of something like exotic dish and trying out with few of these unusually colorful creatures especially Singapore’s Mosaic Reef Crab, think again.Their toxins are not destroyed by heat or cooking. These crabs should never be eaten. Eating them can cause Paralytic Shellfish Poisoning which can lead to death. There is no antidote to their toxins.

Moray Eel

Moray eels belong to the order Anguilliformes which contains 20 families. Morays are members of the family Muraenidae. The 100 species identified by scientists range in size from 2-10 feet. The largest is the giant moray which reaches 10 feet in length and weighs 75 pounds. Many have beautiful color patterns which help to camouflage them in the reef. Because morays keep their mouths open almost all of the time, the insides of their mouths are camouflaged also. The common morays in the Caribbean reefs include the spotted, goldentail and green morays. Morays are nocturnal creatures and can be and to inhabit the waters of the Indian, Pacific and Atlantic oceans.Only five types of morays are known to be poisonous.Their blood is toxic, but the toxic protein it contains is destroyed by cooking. Another thing to watch for when reaching out to dark areas or crevices underwater, Moray’s razor sharp teeth which are ready to strike when probed by bare hands on their hiding place.

Lyngbya Majuscula

Lyngbya is a genus of cyanobacteria that is one of the causes of the human skin irritation called swimmer’s itch. This skin irritation is unrelated to cercarial dermatitis. Some Lyngbya species also cause destruction of aquatic ecosystems when they form dense floating mats in the water.

Sea Anemone   

Sea anemone Triactis producta Klunzinger is an inhabitant of the Red Sea. A clinical case history of a stinging by T. producta which occurred at Eilat, Gulf of Aqaba, Israel is herein reported. The symptoms consisted mainly of pain and swelling of the affected Limb and the production of a pigmented, papular lesion, which became encrusted and indurated and remained sensitive to touch for a period of about 5 weeks. This species is one of the more dangerous species of venomous sea anemones. Aqueous extracts of the crude toxin obtained from undischarged tentacle nematocysts tested by injection in mosquito fish (Gambusia) were found to be stable to drying, room temperatures, several organic solvents and boiling for variable periods of time. This is the first report to appear in the literature on the venomous properties of this sea anemone.

Sea Urchins

Not all Sea Urchins are venomous but one of the most dangerous, the Flower urchins can be deadly. It looks like its body is covered by flowers instead of thorns, but they are in fact venomous and can cause paralysis or, even worse, death. There have been several reports of people killed by Flower Urchins around Japan.

Velvet Sea Slug (Chelidonura varians)

Velvet Sea Slugs are commonly called Blue Doris, Blue Velvet Nudibranch and Head Shield Sea Slug. These type of slugs are found in the Indo-Pacific region. Size of a slug may grow up to a size of three inches with an overall black color with blue stripes. Velvet Sea Slugs are non-aggressive towards the other marine members and they usually thrive in shallow bottoms of sand, in lagoon or on bay. They are poisonous in nature and secretes venomous Hydrozoan Nematocysts. Although these species had been bred to fill up some aquarium owing to their bright colors, extreme care should be taken in handling them.