NARD Diving MedicineDiving MD

Marine Life

Dive teams operate in the water environment, and because of this they must understand and respect it. Man can never conquer the ocean, anyone believing he can has no business on a dive rescue team. Only by working with the sea, can one strive to be one with the sea. By comprehending its flow and creatures will the rescuer safely operate within it.

The creatures that reside in the waters of the world are not monsters of the deep, but creatures ranging in size from the one celled protozoan to the blue whale. The fish and marine mammals rule the sea, with the killer whale as their king, any person entering their world must do so under their rules. Divers, boaters, swimmers, and anyone visiting the water, should know that they are visitors, and should not ravage the home of any marine animal.

People fear what they do not understand. Knowledge brings understanding, and with understanding, a loss of fear. Try to learn about the area you serve, and then impart this to others. By doing this you may reduce accidents by getting people to respect their water environment, and coastlines. Here we are only going to present the plants and creatures that cause the most harm around the water, but remember there are benefits from these creatures.

The survival of some sea animals is partially dependant upon protective or aggressive behavior, and the use of toxic mechanisms. These creatures are divided into three categories: those that bite, those that sting, and those that have spines. Injury from any aquatic creature may result in secondary infection due to bacterial and viral pollution found in all waters. Of the poisonous and venomous fish encountered there will generally have aquatic venoms falling into two classes: for defense and offense (obtaining food).

Defensive venoms are commonly not meant to kill, but to warn intruders away, hence they are quick acting and distinctively very painful. Offensive venoms are meant to kill, or stun pray, and usually is found in the mouth of the creature. These are normally neurotoxic, relatively painless and meant to paralyze. Wounds from either are highly subject to secondary infection.

Poisonous and venomous fish are of a variety of marine life that can release their toxin by one of four routes: 1) Stings, 2) Punctures, 3) Bites and/or Lacerations, and 4) Eating inedible, spoiled, or contaminated seafood.

Stings come from various types. The most common of these types are corals (hydroid), jellyfish (nematocysts), and sea-anemones. These are not the only types, just the most common. The tentacles of many of these animals are lined with stinging cells called nematocysts. Armed with these, the slightest brush can set them off. They are designed to act in one of three ways. Some have a sticky coating to adhere to anything it touches. Others have tentacles that wrap around the object. The last has a harpoon type tip. Stinging capsules called nematocysts contain an inverted thread like stinger coiled within which averts when the capsule fires. This happens every time they are touched, whether the creature is dead, or alive. They may fire immediately, or sometime later when deposited on the skin. Under some conditions the mechanical stimuli such as rubbing the area, or a change in skin pH will cause then to fire. Not all species have nematocysts capable of penetrating human skin, and toxicity of injected venom varies with species, it may be innocuous or lethal. Some individuals may exhibit allergic reactions, or anaphylaxis when stung.

Frequently the victim never sees what stung him. The sting will exhibit itself with burn like welts, occurring in whip like streaks, clusters or signally. The initial pain is sudden, and may be of sufficient intensity to cause shock. It is probable that a number of salt water drowning are the indirect result of contact with nematocysts. Portuguese man-of-war, and sea wasp stings require immediate first aid.

Signs, and symptoms vary in intensity depending on species and extent of the sting. They range from a mild prickly sensation to an intense throbbing, shooting pain, which can result in unconsciousness. There is commonly a reddening of the area, which may manifest as welts, blisters, and/or swelling. Muscle cramps and numbness may occur at the site area, or somewhere else. Nausea and vomiting can develop from the toxin. Depending on the strength of the toxin, or how susceptible the victim is to it, more serious symptoms may develop such as, loss of speech, frothing at the mouth, respiratory difficulty, paralysis, delirium, convulsion, shock, and ending in cardiac arrest.

Treatment involves removing the victim from the water if not already done. Observe for signs of shock, and remove any tentacles using gloves. Meat tenderizer containing papain can be applied to many stings to neutralize the toxin. Rinse liberally with alcohol, to inactivate any intact nematocysts, thus preventing them from firing. Try to avoid rubbing, and never use fresh water to rinse the affected area. Antihistamine given sub-Q should be administered if the victim develops any respiratory difficulties. Benedryl by mouth (PO) is all right as long as the patient is not exhibiting any serious signs. Many victims appear to have shortness of breath but actually are hyperventilating. Cortisone cream can reduce inflammation. If distress develops, keep the victim lying down. Administer BLS, or ALS as needed.

If contact with nematocysts occurs, and no first aid kit is readily available, remember not to grab the affected area. If on another person, caution them not to touch it. Use your knife to remove any tentacles left. Mix some sand with sea water, and place on the area. After a minute or two, rinse the area with sea water. The theory behind this field procedure is that the sand will absorb all poison left on the victim, and then wash it away. It may be debatable as to if this procedure actually works, but it does calm the victim. The reason being is the fact that you are doing something. Psychological support is important to all victims. Saying there is nothing that can be done only worsens the situation

Most aquatic venoms are heat labile meaning they, breakdown when heat is applied. To obtain the best results heat must be used properly. Too little heat for too short a time, will have no effect. The victim can tolerate more heat if the temperature is elevated slowly. Place the affected part in hot water, then slowly add hotter water to obtain the hottest water the victim can stand. Temperatures between 110o and 114o F (43o and 46o C) should be maintained for a minimum of 30 minutes. Very young, and very old people cannot dissipate heat entering the body via the skin very well, and will consequently blister more easily. Hot compresses or total body immersion may be necessary for parts of the body other than extremities

For some toxins a venous tourniquet may be needed. This confines the venom to a limited area by slowing venous return. When properly applied, one finger should be able to be inserted between the tourniquet and skin, and a pulse distal to the tourniquet should be felt. Loosen it for 90 seconds every 10 minutes. Properly utilized, a tourniquet may be life saving in cases of extreme sensitivity or envenomation.

Many species have spines capable of inflicting traumatic, and venomous wounds, such as: stingrays, sea urchins, catfish, and lionfish. The wound site when venomous, has a pale color. Introduction of venom results in instant extreme pain.


  • Establish an airway and administer oxygen 100%

  • Place a venous tourniquet above the sting site if possible.

  • Start an IV normal saline in the opposite extremity to the bite or sting.

  • Give epinephrine 1:1000 sub-Q 0.5ml at the site of sting distal to the tourniquet and give the same amount in the opposite body side arm. Thereafter the dose of 0.5ml in the opposite body side, and may be repeated every 20 minutes until manifestations subside.

  • Monitor cardiac rhythm.

If patient goes into shock:

  • Administer 10ml 1:10,000 epinephrine SLOW IVP. Draw up 250 mg of aminophylline and add it to 250 ml of D5W and hang piggyback to control bronchospasm (indicated by wheezing). Draw up 5ml dopamine (Intropin) or 2ml norepinephrine (Levophed) and add to a different 250ml of D5W and hang piggyback. Adjust infusion rate to blood pressure. Have 100 mg of hydrocortisone ready in a syringe for once patient is stabilized, it is given to minimize the inflammatory reaction.

COELENTERATES (JELLYFISH) Swimmers and scuba divers sustain stings from one of several coelenterates on a daily bases. The stinging apparatus of the group is called a nematocyst. These nematocyst are like little hypos waiting to inject venom on whatever they touch. It is because of these stinging cells that the rescuer must be careful when touching a victim, because they act like a contact poison. These stings can be mild to severe and every year people die from coelenterates. The most common are:

Portuguese Man-of-War (Physalia physalis) that depends mainly on the wind, currents, and tides for locomotion. It has a distinct blue, balloon like float that can be up to 12 inches in length. Under the float are numerous tentacles reaching lengths to 100 feet. These tentacles contain about 700 to 900 nematocysts per inch of tentacle. The man-of-war is found floating on the water or washed up on beaches. When beached the venom in the stinging cells remains potent for several days.

Sea Wasp (Chiropsalmus quadrigatus) found in most North American waters, it is considered as venomous as a large Portuguese man-of-war, while the Australian variety may cause death in 3 to 8 minutes. It is a free swimming jellyfish that has a square bell shape. It has contractible tentacles on each of the four corners. It is a strong swimmer using active pulsations of the bell.

Moon Jelly (Aurelia aurita) a saucer shaped bell jellyfish measuring up to 12 inches with numerous short tentacles all around it. The center of the bell has a leaf clover design in the center being either yellow (female) or lavender (male). It is capable to move on its own, but is also carried on the currents and tides

After coming in contact with the nematocysts, the victim will fell an intense burning sensation with marked erythema. Extensive stings by the man-of-war and sea wasp produce extreme throbbing or shooting pains, LOC, muscular cramping, abdominal rigidity, nausea, vomiting, severe back pain, loss of speech, frothing at the mouth, sensation of loss of airway, respiratory difficulty, paralysis, delirium, convulsions and death. In nonfatal stings permanent pigmented scarring may occur. When sever respiratory symptoms are present follow anaphylactic protocol.

Treatment is directed to alleviating effects of the poison and relief of pain, there are no known antidotes. Remove any adherent tentacles with self protection. Next splash a copious amount of alcohol over the involved area, this prevents further stinging by "fixing" all remaining nematocyst. Then apply a generous amount of Adolph's Unseasoned Meat Tenderizer. Meat tenderizer contains the proteolytic enzyme papain, which neutralizes the protein toxin. Administer an antihistamine IM promptly. Intravenous injection of calcium gluconate may be needed to control muscle spasms. If pain is severe, a narcotic analgesic is indicated either IM or IV.

STINGRAYS are quite numerous in the shallow waters of most bays and all along the Gulf coast where swimming and wadding is popular. Stingrays have a sharp spine covered by a venomous integumentary sheath. Injury is sustained when the fish is accidentally stepped on. Upon contact the ray lashes out with its tail that has a venomous barb. The barb enters the soft tissue producing a jagged laceration, a typical puncture wound or a stellate wound. Portions of the saw tooth stinger frequently are left in the wound, with leaking of venom from the stinger. It causes a laceration like wound. The predominant symptom is a sharp intense shooting pain. The reaction is usually local, but the venom may produce changes in the cardiovascular, respiratory, nervous, or urinary systems. The majority of these stings require treatment for secondary infection. Combat the effects of stingray venom by immersing the injured limb in water as hot as can be tolerated, for 30 to 90 minutes, the relief of pain is immediate, and dramatic. Do not use ammonia on a stingray wound. Elevate the injured limb to reduce swelling. Prevent infection by removing foreign matter.

The pain is excruciating, radiating proximal thus distinguishing the injury from trauma produced by an inanimate object. Muscle weakness progressing to paralysis mat occur. In a small number of cases the pain may last for several hours with decreasing blood pressure, tachycardia, chills, vomiting and vascular collapse.

Treatment is as soon as possible submerge the affected part in tap water as hot as can be tolerated, by the victim, for at least 30-60 minutes. The venom is a heat labile protein. Soaking does two things: deactivation of the venom and reduction in pain. After soaking, irrigate with an antibacterial solution. Tease out any barb. Then replace the part in hot water again for another hour. DO NOT SUTURE THE WOUND! Apply a bulky pressure dressing, give an antihistamine parenterally. Some cases may require morphine for pain. Follow up care is change the dressing frequently and inspect for infection, foreign body reaction, or anaerobic granulomatous lesions (Mycobacterium marinum).

Lionfish, California sculpin, stonefish, and scorpion fish, have venomous fin spines capable of inflicting potentially lethal injuries. They are found in the warmer waters of North America and are popular in salt water aquariums. After contact there is immediate, and intense pain with swelling, which may progress to the axilla, or groin. Treat with heat, the wound should be managed as with a stingray, heat should be promptly and properly applied. In severe cases with systemic effects there is excruciating pain, primary shock, pulmonary edema, and dysrhythmias. The type of fish should be known for proper antivenom. In the field contact Poison Control, and transport to the hospital for evaluation.

Catfish have venomous dorsal and pectoral fins, that can inflict severe and potentially contaminated injuries. The wound usually produces a throbbing pain that subsides in about one hour. It should be cleaned, irrigated, and a broad spectrum anti-biotic given to avoid secondary infection.

Sea urchins have spines, and pedicellaries that are tiny fang like organs among the spines. They may inflict venomous and traumatic injuries, based on the species. When barbs are present on the spines they point towards the tip of the spine making continued penetration almost impossible. Remove as much of the spine as possible. Some may require surgical removal. With sea urchins apply a strong ammonia solution in hot water.

Bristleworms are members of the annelida family that are segmented worms. They are wide spread found in warm tropical, or moderate areas. They are especially common in the Gulf of Mexico, and tropical Pacific. The venom causes swelling and minor pain. Remove bristle worm stingers with tape, and apply alcohol or vinegar.

When diving on or near a coral reef, protect the body with long sleeves, trousers, gloves, and sox or rock boots. A long sleeved jumpsuit is ideal for protection, because body heat is lost in even the warmest water. Coral is extremely sharp, some having razor edges. If untreated it can develop into an ulcer, and often becomes infected. Some, such as fire coral, sting similar to jellyfish.

Cone shells are responsible for killing many people every year. They are widespread, and normally found under rocks, in coral or on the beach. Cone shells are popular by beach combers because of their colorful spiral designs. The animal has a distinct head, one or two pairs of tentacles, two eyes and a large foot. The venom apparatus is at the narrow end of the shell and is able to reach most of it. Their stings have a 25% mortality. Symptoms develop within minutes of the sting, and can last up to 24 hours. No antivenom is available. The victim will fell a burning or stinging sensation at the wound site followed by numbness and tingling. This numbness and tingling may spread to the rest of the body, involving the mouth and lips. Due to mouth involvement, speech and swallowing will become difficult. Other symptoms include respiratory distress and visual disturbances.

Treatment includes laying the victim down and applying a venous tourniquet above the wound site. Treat the victim the same as a snake bite and treat for shock. Start an IV lifeline and monitor cardiac rhythm. Victim may respiratory arrest at any time be prepared.

One of the most venomous creatures of the sea is the sea snake. All sea snakes and some octopus bites contain a neurotoxin of varying toxicity. The sea snake uses its venom to obtain live food and is reluctant to waste it. It is believed that it can control the amount of venom injected at any one time, so defensive bites usually contain a minimal amount of toxin. Deadly bites to man are rare. Local effects from sea snake and octopus bites are usually minimal. Octopus bites may bleed profusely. There is an octopus found in Australia that has caused several deaths, known as the Blue-ringed octopus. It rarely gets more than four inches long, yet its bite is often fatal.

Identifying venomous fish and their habits can help in avoiding contact with them. Do not handel these marine life. When diving, or walking in coastal areas wear hard sole booties or tennis shoes. Many of these wounds are extremely painful, and must be treated with painkillers.

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