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.
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).
Figure 5c-1. Types of Sharks.
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| 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
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.
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2. | Treat for shock by laying the patient down and elevating his feet. |
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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.
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4. | Initial stabilization procedures should include attention to the airway, breathing,
and circulation, followed by a complete evaluation for multiple trauma.
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5. | Transport the victim to a medical facility as soon as possible. Reassure the
patient.
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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.
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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.
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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.
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9. | Administer tetanus prophylaxis: Tetanus toxoid, 0.5 ml intramuscular (IM)
and tetanus immune globulin, 250 to 400 units IM.
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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.
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11. | Acute surgical repair, reconstructive surgery, and hyperbaric oxygen (HBO)
adjuvant therapy improving tissue oxygenation may all be needed.
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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.
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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.
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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.
First aid and treatment would follow the same general
principles as those used for a shark bite (paragraph 5C-2.1.2).
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.
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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.
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.
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 puncture 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.
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Extreme care should be used when reaching into holes or crevices.
Avoid provoking or attempting to dislodge an eel from its hole.
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.
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.
Divers should avoid these mammals when in the water.
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.
