Often mistaken for harmless plants or nonliving gelatinous masses, marine invertebrates and coral can cause allergic reactions, stings and often contain toxic venomous substances that can cause severe injury to divers if encountered. We have listed a few such hazardous creatures, which can cause to serious harm to unaware or inattentive divers through contact.  Essentially underwater contact irritants consist of any substance that when the skin comes in contact with a substance that acts as an irritant and causes contact dermatitis. This is the second part of our two part series on Scuba Diving touch-me-nots. If you missed the first part Click Here.

Sea Cucumbers

Though Sea Cucumbers are seemingly harmless, when under threat, these animals will expel  holothurin which is a white sticky like substance from their Cuvierian organ.Holothurin is a strong poison and the venom of the sea cucumbers quickly weakens the muscles of the enemy. Sea Cucumber venom is toxic to humans if the Cuvierian tubules come into contact with the eyes, the result may be permanent blindness.

Fire Coral

Fire Coral also known as Stinging or Red Sea Coral belongs to the Milleporina order of species and contrary to popular belief isn’t really a coral at all. Fire corals are marine organisms that form colonies that look just like real coral; they are actually closely related to the jellyfish family and other stinging anemones.   The Fire Coral gets its name from the painful burning sting that it inflicts on the unwary diver that brushes against it. A fire Coral sting can cause intense pain and can be felt from two days to up to two weeks. (Also Read: Playing With Fire Underwater: Fire Coral Demystified)

Crown-of-Thorns Starfish

Out of all starfish species, the Crown-of-thorns starfish is probably the most dangerous to divers. The sharp spines on the sides of the starfish’s limbs resemble thorns and create a crown-like shape, giving the creature its name. These thorns are very sharp and are capable of piercing through wetsuits and other clothing and are contain a neurotoxin that can cause onset of edema, erythema ,pain, as well as nausea and vomiting. Crown-of-thorn starfish are found in  tropical coral reefs in the Red Sea, the Indian Ocean, and the Pacific Ocean.

Hydroids

Hydroids are feathery plants like creatures closely related to jellyfish, with stinging cells, and are sometimes referred to as fireweed. Hydroids are actually colonies of animals equipped with strong stinging cells (nematocysts) used to capture prey and for defense. Attached to virtually any firm surface including rocks, seaweeds, and man-made objects including docks and mooring lines Hydroids are one of the primary causes of itching and skin irritation for divers that accidentally come in contact with this tiny creatures.  Two species to avoid in particular are the white, fine feathery ones known as the Feather Hydroid  and the denser yellow/brown variety.

Sea Urchins

Divers are especially wary of these creatures mainly due to the fact that accidental stings while walking in a shallow reef, or touching one accidentally while Scuba diving can be a painful proposition. The spines of sea urchins remain in the wound making wound heal slowly. Sea urchins inject a small amount of venom when stinging, but the amount is negligible to cause any serious injury , around 10 species of Urchins are poisonous but there are a few that are deadly. Sea urchin stings must be washed thoroughly and rinsed with vinegar to wash out the stings and then watched over the next couple of days for signs of infection. Divers should be constantly vigilant where they place their hands, to avoid an accidental encounter with these spiny devils.

* Photo credits: photos by Nemo’s Great Uncle, jon hanson, enje, Dungodung on flickr

A question frequently asked by Scuba Divers is what are the toxic/stinging/hazardous coral and marine life you should avoid touching while Scuba diving? Most divers know and are aware of the toothy creatures to keep away from while diving, but often mistaken for harmless plants or nonliving gelatinous masses are marine invertebrates and coral that can cause allergic reactions, stings and often contain toxic venous substances that can cause severe injury to divers if encountered.

We have listed a few such hazardous creatures,and things to look out for when diving, which can cause serious harm to unaware or inattentive divers through contact.  Essentially underwater contact irritants consist of any substance that when the skin comes in contact with a substance that acts as an irritant and causes contact dermatitis.

Sponges
Although most sea sponges are harmless and contact results in minimal effects or abrasions, except for species that produce crinitoxins and can cause irritation and dermatitis. There are three species in particular which produce contact dermatitis; red-beard sponge (Micronia prolifera), fire sponge (Tedania ignis) and poison-bun sponge (Fibula nolitangere).

The red beard sponge has thick, intertwining branches that vary in color from bright red to orange and are abundantly found in the waters of northeastern United States

Fire Sponge named for the burning sensation and rash it produces when touched is large and usually Bright red or red-orange and lobed, and smooth, with few large pores. Found commonly in the Western Atlantic and Caribbean coastal waters, from Florida to Mexico; Bahamas and the West Indies.

You often feel nothing when you first touch a poisonous sponge. A burning, stinging, or itching feeling begins hours, or even days, after initial contact. Effects ranging from mild to severe pain, and local inflammation, redness, joint-pain and swelling may occur after touching a toxic sponge.

Sea Anemones

While most Sea Anemones are relatively harmless to humans, a few of them produce strong toxins that produce severe effects. Sea anemones are close relatives of jellyfish and corals and bear similar stinging tentacles. The most toxic of Anemones is the Actinodendron plumosum known as the stinging anemone or Hell’s Fire anemone due to its very painful sting. Found primarily in the indo-pacific ,these anemones that look more like soft coral with fir tree like/ leaf shaped or feather-like appearance branches, that possess nematocysts (tiny venous stinging cells) that cause  pain, burning sensation and/or itching. The Hell’s Fire Anemone can be light yellowish green, tan, brown, light green or gray and can be recognized by its frilly or feathery appearance.

Fireworms/ Bristleworms

A fireworm which is a type of bristleworm is a bright orange and red colored flattened segmented worm, reaching 30cm in length, has  of white bristles along each side. The bristles are hollow and venom-filled which easily penetrate the flesh and break off if this worm is touched.  They produce an intense irritation in the area of contact, The fireworm is abundant on reefs, beneath stones in rocky or sea grass areas and on some muddy bottoms.   It is found throughout the tropical western Atlantic.

Continued in Scuba Diving Touch Me Nots (Part 2)

*Photo Credits: photos from flickr by jtu, budak, alphonsator

What is Fire Coral?

Most Scuba divers who have dived in tropical or sub-tropical reefs will have been cautioned about getting stung by the notorious Fire Coral, and will have filed away the information as just one of the many things that can sting or harm you underwater.

Fire Coral also known as Stinging or Red Sea Coral belongs to the Milleporina order of species and contrary to popular belief isn’t really a coral at all. Fire corals are marine organisms that form colonies that look just like real coral; they are actually closely related to the jellyfish family and other stinging anemones.   The Fire Coral gets its name from the painful burning sting that it inflicts on the unwary diver that brushes against it.

How does it look? How can I identify Fire Coral?

Fire Coral is unfortunately rather polymorphic and can appear in several physical forms. Sometimes it appears heavily branched and delicate in appearance, other times it is more, fan-blade shaped and massive. Most common forms it appears is either branched, plated, or encrusted.   It is believed to have close to 50 varieties of Fire Coral species making it rather hard to describe. Most of the time Fire corals have a bright yellow-green and brown skeletal covering fading to a whitish hue at the tips, and will be soft and hairy  and rounded up close.

Where does it exist?

Fire Coral are widely distributed in tropical and subtropical waters. Primarily occurs in the Indian and Pacific Oceans.

Fire corals form extensive outcrops on projecting parts of the reef where the tidal currents are strong. They are also abundant on upper reef slopes and in lagoons, and occur down to depths of 40 meters.

What does it Do?

Fire Coral belongs to the family of Milleporina,  Millepora means ‘many pores’. Upon close inspection, the coral appears to have long fine hairs that protrude from the skeleton. The hairs possess clusters of stinging cells (nematocysts) that inflict the stings on human skin. These hairs capture prey, and help feed the coral.

Divers often mistake fire coral for sea weed or normal coral and may brush against it or lean on it for support. Upon contact the very small nematocysts on the corals hairs release toxins while the sharp calcified exo-skeleton cuts the divers’ skin. A fire Coral sting can cause intense pain and can be felt from two days to up to two weeks. The degree of pain varies on the duration of contact and the number of nematocysts that entered the wound.

Prevention

The best method of prevention is to practice and master Buoyancy control and avoid unnecessary contact with any coral.  Wearing full wetsuits & diving gloves is a good way to ensure you don’t accidentally get in contact with Fire Coral.

What do I do if I get stung?

The first step is to rinse the wound or affected area with salt water, as fresh water will increase the pain. Secondly use vinegar (acetic acid) or Isopropyl Alcohol to kill any remaining stinging cells clinging to your skin and help break down the toxin. Use tweezers to put out any stinging hairs. Immobilize the affected limb to prevent spreading and Finally, apply hydrocortisone cream as necessary to reduce inflammation. It is also critical to watch the wound for infection, which will have to be treated with antibiotics by a doctor.

If the diver displays symptoms like shortness of breath and swelling of the tongue, neck and face, he has probably developed an allergic reaction to the sting and should be treated for allergy and rushed to a hospital.

Photos by: Nick Hobgood, Tim Sheerman-Chase, Scary Cow, welshcathy, Paul and Jill, Craig Grobler