C2 Predatory Marine Animals

5C-2.1 Sharks. Shark attacks on humans are infrequent. Since 1965, the annual recorded number of shark attacks is only 40 to 100 worldwide. These attacks are unpredictable and injuries may result not only from bites, but also by coming in contact with the shark's skin. Shark skin is covered with very sharp dentine appendages, called denticles, which are reinforced with tooth-like centers. Contact with shark skin can lead to wide abrasions and heavy bleeding.

5C-2.1.1 Shark Pre-Attack Behavior. Pre-attack behavior by most sharks is somewhat predictable. A shark preparing to attack swims with an exaggerated motion, its pectoral fins pointing down in contrast to the usual flared out position, and it swims in circles of decreasing radius around the prey. An attack may be heralded by unexpected acceleration or other marked change in behavior, posture, or swim patterns. Should surrounding schools of fish become unexplainably agitated, sharks may be in the area. Sharks are much faster and more powerful than any swimmer. All sharks must be treated with extreme respect and caution (see Figure 5C-1).

5C-2.1.2 First Aid and Treatment.

1. Bites may result in a large amount of bleeding and tissue loss. Take immediate action to control bleeding using large gauze pressure bandages. Cover wounds with layers of compressive dressings preferably made with gauze, but easily made from shirts or towels, and held in place by wrapping the wound tightly with gauze, torn clothing, towels, or sheets. Direct pressure with elevation or extreme compression on pressure points will control all but the most serious bleeding. The major pressure points are: the radial artery pulse point for the hand; above the elbow under the biceps muscle for the forearm (brachial artery); and the groin area with deep finger-tip or heel-of-the-hand pressure for bleeding from the leg (femoral artery). When bleeding cannot be controlled by direct pressure and elevation or pressure points, a tourniquet or ligature may

Figure 5C-1. Types of Sharks.

be needed to save the victim's life even though there is the possibility of loss of the limb. Tourniquets are applied only as a last resort and with only enough pressure to control bleeding. Do not remove the tourniquet. The tourniquet should be removed only by a physician in a hospital setting. Loosening of a tourniquet may cause further shock by releasing toxins into the circulatory system from the injured limb as well as continued blood loss.

2. Treat for shock by laying the patient down and elevating his feet.

3. If medical personnel are available, begin intravenous (IV) Ringer's lactate or normal saline with a large-bore cannula (16 or 18 ga). If blood loss has been extensive, several liters should be infused rapidly. The patient's color, pulse, and blood pressure should be used as a guide to the volume of fluid required. Maintain an airway and administer oxygen. Do not give fluids by mouth. If the patient's cardiovascular state is stable, narcotics may be administered in small doses for pain relief. Observe closely for evidence of depressed respirations due to the use of narcotics.

4. Initial stabilization procedures should include attention to the airway, breathing, and circulation, followed by a complete evaluation for multiple trauma.

5. Transport the victim to a medical facility as soon as possible. Reassure the patient.

6. Should a severed limb be retrieved, wrap it in bandages, moisten with saline, place in a plastic bag and chill, but not in direct contact with ice. Transport the severed limb with the patient.

7. Clean and debride wounds as soon as possible in a hospital or controlled environment. Since shark teeth are cartilage, not bone, and may not appear on an X-ray, operative exploration should be performed to remove dislodged teeth.

8. Consider X-ray evaluation for potential bone damage due to crush injury. Severe crush injury may result in acute renal failure due to myoglobin released from injured muscle, causing the urine to be a smoky brown color. Monitor closely for kidney function and adjust IV fluid therapy appropriately.

9. Administer tetanus prophylaxis: Tetanus toxoid, 0.5 ml intramuscular (IM) and tetanus immune globulin, 250 to 400 units IM.

10. Culture infected wounds for both aerobes and anaerobes before instituting broad spectrum antibiotic coverage; secondary infections with Clostridium and Vibrio species have been reported frequently.

11. Acute surgical repair, reconstructive surgery, and hyperbaric oxygen (HBO) adjuvant therapy improving tissue oxygenation may all be needed.

12. In cases of unexplained decrease in mental status or other neurological signs and symptoms following shark attack while diving, consider arterial gas embolism or decompression sickness as a possible cause.

5C-2.2 Killer Whales. Killer whales live in all oceans, both tropical and polar. This whale is a large mammal with a blunt, rounded snout and high black dorsal fin (Figure 5C-2). The jet black head and back contrast sharply with the snowy-white underbelly. Usually, a white patch can be seen behind and above the eye. The killer whale is usually observed in packs of 3 to 40 whales. It has powerful jaws, great weight, speed, and interlocking teeth. Because of its speed and carnivorous habits, this animal should be treated with great respect. There have been no recorded attacks on humans.

Figure 5C-2. Killer Whale.

5C-2.2.1 Prevention. When killer whales are spotted, all personnel should immediately leave the water. Extreme care should be taken on shore areas, piers, barges, ice floes, etc., when killer whales are in the area.

5C-2.2.2 First Aid and Treatment. First aid and treatment would follow the same general principles as those used for a shark bite (paragraph 5C-2.1.2).

5C-2.3 Barracuda. Approximately 20 species of barracuda inhabit the oceans of the West Indies, the tropical waters from Brazil to Florida and the Indo-Pacific oceans from the Red Sea to the Hawaiian Islands. The barracuda is a long, thin fish with prominent jaws and teeth, silver to blue in color, with a large head and a V-shaped tail (Figure 5C-3). It may grow up to 10 feet long and is a fast swimmer, capable of striking rapidly and fiercely. It will follow swimmers but seldom attacks an underwater swimmer. It is known to attack surface swimmers and limbs dangling in the water. Barracuda wounds can be distinguished from those of a shark by the tooth pattern. A barracuda leaves straight or V-shaped wounds while those of a shark are curved like the shape of its jaws. Life threatening attacks by barracuda are rare.

Figure 5C-3. Barracuda.

5C-2.3.1 Prevention. Barracuda are attracted by any bright object. Avoid wearing shiny equipment or jewelry in waters when barracudas are likely to be present. Avoid carrying speared fish, as barracuda will strike them. Avoid splashing or dangling limbs in barracuda-infested waters.

5C-2.3.2 First Aid and Treatment. First aid and treatment follow the same general principles as those used for shark bites (paragraph 5C-2.1.2). Injuries are likely to be less severe than shark bite injuries.

5C-2.4 Moray Eels. While some temperate zone species of the moray eel are known, it primarily inhabits tropical and subtropical waters. It is a bottom dweller and is commonly found in holes and crevices or under rocks and coral. It is snake-like in both appearance and movement and has tough, leathery skin (Figure 5C-4). It can grow to a length of 10 feet and has prominent teeth. A moray eel is extremely territorial and attacks frequently result from reaching into a crevice or hole occupied by the eel. It is a powerful and vicious biter and may be difficult to dislodge after a bite is initiated. Bites from moray eels may vary from multiple small punc ture wounds to the tearing, jagged type with profuse bleeding if there has been a struggle. Injuries are usually inflicted on hands or forearms.

Figure 5C-4. Moray Eel.

5C-2.4.1 Prevention. Extreme care should be used when reaching into holes or crevices. Avoid provoking or attempting to dislodge an eel from its hole.

5C-2.4.2 First Aid and Treatment. Primary first aid must stop the bleeding. Direct pressure and raising the injured extremity almost always controls bleeding. Arrange for medical follow-up. Severe hand injuries should be evaluated immediately by a physician. Mild envenomation may occur from a toxin that is released from the palatine mucosa in the mouth of certain moray eels. The nature of this toxin is not known. Treatment is supportive. Follow principles of wound management and tetanus prophylaxis as in caring for shark bites. Antibiotic therapy should be instituted early. Immediate specialized care by a hand surgeon may be necessary for tendon and nerve repair of the hand to prevent permanent damage and loss of function of the hand.

5C-2.5 Sea Lions. The sea lion inhabits the Pacific Ocean and is numerous on the West Coast of the United States. It resembles a large seal. Sea lions are normally harmless; however, during the breeding season (October through December) large bull sea lions can become irritated and will nip at divers. Attempts by divers to handle these animals may result in bites. These bites appear similar to dog bites and are rarely severe.

5C-2.5.1 Prevention. Divers should avoid these mammals when in the water.

5C-2.5.2 First Aid and Treatment.

1. Control local bleeding.

2. Clean and debride wound.

3. Administer tetanus prophylaxis as appropriate.

4. Wound infections are common and prophylactic antibiotic therapy is advised. 5C-3 VENOMOUS MARINE ANIMALS

5C-3.1 Venomous Fish (Excluding Stonefish, Zebrafish, Scorpionfish). Identification of a fish following a sting is not always possible; however, symptoms and effects of venom do not vary greatly. Venomous fish are rarely aggressive and usually contact is made by accidentally stepping on or handling the fish. Dead fish spines remain toxic (see Figure 5C-5). Venom is generally heat-labile and may be decomposed by hot water. Local symptoms following a sting may first include severe pain later combined with numbness or even hypersensitivity around the wound. The wound site may become cyanotic with surrounding tissue becoming pale and swollen. General symptoms may include nausea, vomiting, sweating, mild fever, respiratory distress and collapse. The pain induced may seem disproportionately high to apparent severity of the injury. Medical personnel should be prepared for serious anaphylactic reactions from apparently minor stings or envenomation.

Figure 5C-5. Venomous Fish. Shown is the weeverfish.

5C-3.1.1 Prevention. Avoid handling suspected venomous fish. Venomous fish are often found in holes or crevices or lying well camouflaged on rocky bottoms. Divers should be alert for their presence and should take care to avoid them.

5C-3.1.2 First Aid and Treatment.

1. Get victim out of water; watch for fainting.

2. Lay patient down and reassure.

3. Observe for signs of shock.

4. Wash wound with cold, salt water or sterile saline solution. Surgery may be required to open up the puncture wound. Suction is not effective to remove this toxin.

5. Soak wound in hot water for 30 to 90 minutes. Heat may break down the venom. The water should be as hot as the victim can tolerate but not hotter than 122°F (50°C). Immersion in water above 122°F (50°C) for longer than a brief period may lead to scalding. Immersion in water up to 122°F (50°C) should therefore be brief and repeated as necessary. Use hot compresses if the wound is on the face. Adding magnesium sulfate (epsom salts) to the water offers no benefit.

6. Calcium gluconate injections, diazepam, or methocarbamol may help to reduce muscle spasms. Infiltration of the wound with 0.5 percent to 2.0 percent xylocaine with no epinephrine is helpful in reducing pain. If xylocaine with epinephrine is mistakenly used, local necrosis may result from both the toxin and epinephrine present in the wound. Narcotics may also be needed to manage severe pain.

7. Clean and debride wound. Spines and sheath frequently remain. Be sure to remove all of the sheath as it may continue to release venom.

8. Tourniquets or ligatures are no longer advised. Use an antiseptic or antibiotic ointment and sterile dressing. Restrict movement of the extremity with immobilizing splints and cravats.

9. Administer tetanus prophylaxis as appropriate.

10. Treat prophylactically with topical antibiotic ointment. If delay in treatment has occurred, it is recommended that the wound be cultured prior to administering systemic antibiotics.

5C-3.2 Highly Toxic Fish (Stonefish, Zebra-fish, Scorpionfish). Stings by stonefish, ze-brafish, and scorpionfish have been known to cause fatalities. While many similarities exist between these fish and the venomous fish of the previous section, a separate section has been included because of the greater toxicity of their venom and the availability of an antivenin. The antivenin is specific for the stonefish but may have some beneficial effects against the scorpionfish and zebrafish. Local symptoms are similar to other fish envenomation except that pain is more severe and may persist for many days. Generalized symptoms are often present and may include respiratory failure and cardiovascular collapse. These fish are widely distributed in temperate and tropical seas and in some arctic waters. They are shallow-water bottom dwellers. Stonefish and scorpionfish are flattened vertically, dark and mottled. Zebrafish are ornate and feathery in appearance with alternating patches of dark and light color (see Figure 5C-6).

5C-3.2.1 Prevention. Prevention is the same as for venomous fish (paragraph 5C-3.1.1).

5C-3.2.2 First Aid and Treatment.

Figure 5C-6. Highly Toxic Fish.

1. Give the same first aid as that given for venomous fish (paragraph 5C-3.1.2).

2. Observe the patient carefully for the possible development of life-threatening complications. The venom is an unstable protein which acts as a myotoxin on skeletal, involuntary, and cardiac muscle. This may result in muscular paralysis, respiratory depression, peripheral vasodilation, shock, cardiac dysrhythmias, or cardiac arrest.

3. Clean and debride wound.

4. Antivenin is available from Commonwealth Serum Lab, Melbourne, Australia (see Reference 4 at end of this appendix for address and phone number). If antivenin is used, the directions regarding dosage and sensitivity testing on the accompanying package insert should be followed and the physician must be ready to treat for anaphylactic shock (severe allergic reaction). In brief, one or two punctures require 2,000 units (one ampule); three to four punctures, 4,000 units (two ampules); and five to six punctures, 6,000 units (three ampules). Antivenin must be delivered by slow IV injection and the victim closely monitored for anaphylactic shock.

5. Institute tetanus prophylaxis, analgesic therapy and antibiotics as described for other fish stings.

5C-3.3 Stingrays. The stingray is common in all tropical, subtropical, warm, and temperate regions. It usually favors sheltered water and will burrow into sand with only eyes and tail exposed. It has a bat-like shape and a long tail (Figure 5C-7). Approximately 1,800 stingray attacks are reported annually in the U.S. Most attacks occur when waders inadvertently step on a ray, causing it to lash out defensively with its tail. The spine is located near the base of the tail. Wounds are either of the laceration or puncture type and are extremely painful. The wound appears swollen and pale with a blue rim. Secondary wound infections are common. Systemic symptoms may be present and can include fainting, nausea, vomiting, sweating, respiratory difficulty, and cardiovascular collapse.

5C-3.3.1 Prevention. In shallow waters which favor stingray habitation, shuffle feet on the bottom and probe with a stick to alert the rays and chase them away.

5C-3.3.2 First Aid and Treatment.

1. Give the same first aid as that given for venomous fish (paragraph 5C-3.1.2). No antivenom is available.

2. Institute hot water therapy as described under fish envenomation.

3. Clean and debride wound. Removal of the spine may additionally lacerate tissues due to retropointed barbs. Be sure to remove integumental sheath as it will continue to release toxin.

4. Observe patient carefully for the possible development of life-threatening complications. Symptoms can include cardiac dysrhythmias, hypotension, vomiting, diarrhea, sweating, muscle paralysis, respiratory depression, and cardiac arrest. Fatalities have been reported occasionally.

5. Institute tetanus prophylaxis, analgesic therapy, and broad-spectrum antibiotics as described for fish envenomation.

5C-3.4 Coelenterates. Hazardous types of coelenterates include: Portuguese man-of-war, sea wasp or box jellyfish, sea nettle, sea blubber, sea anemone, and rosy anemone (Figure 5C-8). Jellyfish vary widely in color (blue, green, pink, red, brown) or may be transparent. They appear to be balloon-like floats with tentacles dangling down into the water. The most common stinging injury is the jellyfish sting. Jellyfish can come into direct contact with a diver in virtually any oceanic region, worldwide. When this happens, the diver is exposed to literally thousands of

minute stinging organs in the tentacles called nematocysts. Most jellyfish stings result only in painful local skin irritation.

The sea wasp or box jellyfish and Portuguese man-of-war are the most dangerous types. The sea wasp or box jellyfish (found in the Indo-Pacific) can induce death within 10 minutes by cardiovascular collapse, respiratory failure, and muscular paralysis. Deaths from Portuguese man-of-war stings have also been reported. Even though intoxication from ingesting poisonous sea anemones is rare, sea anemones must not be eaten.

5C-3.4.1 Prevention. Do not handle jellyfish. Beached or apparently dead specimens may still be able to sting. Even towels or clothing contaminated with the stinging nematocysts may cause stinging months later.

5C-3.4.2 Avoidance of Tentacles. In some species of jellyfish, tentacles may trail for great distances horizontally or vertically in the water and are not easily seen by the diver. Swimmers and divers should avoid close proximity to jellyfish to avoid contacting their tentacles, especially when near the surface.

5C-3.4.3 Protection Against Jellyfish. Wet suits, body shells, or protective clothing should be worn when diving in waters where jellyfish are abundant. Petroleum jelly applied to exposed skin (e.g., around the mouth) helps to prevent stinging, but caution should be used since petroleum jelly can deteriorate rubber products.

5C-3.4.4 First Aid and Treatment. Without rubbing, gently remove any remaining tentacles using a towel or clothing. For preventing any further discharge of the stinging nematocysts, use vinegar (dilute acetic acid) or a 3- to 10-percent solution of acetic acid. An aqueous solution of 20 percent aluminum sulfate and 11 percent surfactant (detergent) is moderately effective but vinegar works better. Do not use alcohol or preparations containing alcohol. Methylated spirits or methanol, 100 percent alcohol and alcohol plus seawater mixtures have all been demonstrated to cause a massive discharge of the nematocysts. In addition, these compounds may also worsen the skin inflammatory reaction. Picric acid, human urine, and fresh water also have been found to either be ineffective or even to discharge nemato-cysts and should not be used. Rubbing sand or applying papain-containing meat tenderizer is ineffective and may lead to further nematocysts discharge and should not be used. It has been suggested that isopropyl (rubbing) alcohol may be effective. It should only be tried if vinegar or dilute acetic acid is not available.

Figure 5C-8. Coelenterates. Hazardous coelenterates include the Portuguese Man-of-War (left) and the sea wasp (right).

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