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ABOUT ELASMODVR

ANDY MURCH BIO

 

WHAT IS ELASMODIVER?

Not just Shark Pictures: Elasmodiver contains photos of sharks, skates, rays, and chimaera's from around the world. Elasmodiver began as a simple web based shark field guide to help divers find the best places to encounter the different species of sharks and rays that live in shallow water but it has slowly evolved into a much larger project containing information on all aspects of shark diving and shark photography.

There are now more than 10,000 shark pictures  and sections on shark evolution, biology, and conservation. There is a large library of reviewed shark books, a constantly updated shark taxonomy page, a monster list of shark links, and deeper in the site there are numerous articles and stories about shark encounters. Elasmodiver is now so difficult to check for updates, that new information and pictures are listed on an Elasmodiver Updates Page that can be accessed here:

WHAT'S NEW?

Shark picture - green sawfish

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SHARK ATTACKS

 

Shark Attack Pictures

 

Identifying the perpetrators.

Of the 465 or more species of sharks that are currently described, only a handful are regularly implicated in shark attacks. The most commonly identified (or perhaps misidentified) sharks include the Bull shark, White shark, Tiger shark, and various reef sharks. Historically Sandtiger sharks (AKA Grey nurse sharks in Australia, and Ragged tooth sharks in Southern Africa) were held responsible for many attacks due to their menacing appearance. They have, more recently, been found 'not guilty' in the majority of cases but the bad press that they initially received plus their docile nature when in contact with spear fishermen, left them wide open to exploitation and their numbers have been seriously depleted. It is estimated that the schools once common off the East coast of Australia have dwindled to the point of pending extinction with somewhere around 300 individuals remaining.

In most attacks where the shark escapes, it is difficult (if not impossible) to identify the exact species involved. One of the ways that shark attack investigators figure out who is the culprit in an attack is by the examination of teeth that are sometimes left at the scene having been torn from the sharks jaw during the struggle or embedded in the victims flesh or equipment. For example; teeth are sometimes lodged in surf boards during attacks on surfers.

Another good way to identify individual shark species is by measuring the bite radius, the shape of the wound, and the clean or ragged cut of the teeth. For example; a Tiger shark which has an imposing set of cutting teeth capable of sheering through the shells large sea turtles, would leave a cleanly severed bite out of its victim. Whereas, a Sandtiger or Mako Shark which has dagger-like grasping teeth would leave a ragged wound if trying to pull away a portion of flesh.

It is often difficult for victims and observers to report objectively on their experiences due to the traumatic nature of the encounters. This combined with a general public's lack of knowledge of shark species leaves investigators lacking for accurate information.

Sometimes, geographic location is the best clue to identification. Some species inhabit areas where few other large sharks enter such as the freshwater range of Bull sharks. Attacks occurring far up river are inevitably attributed to this species although in some areas there are other fresh water sharks which may be responsible such as the Ganges shark in the river systems of India.

Bull sharks are indeed one of the most gregarious of shark species and have been implicated in attacks as far reaching as New Jersey to South Africa, and the Zambezi River to Lake Nicaragua.

In attacks off of the surfing beaches of California, White sharks are most commonly implicated. Although other species inhabit this area (such as Blue sharks), the White shark is responsible in the majority of cases as its natural behavior and tendency to frequent surf zones lend to the likelihood of attack.

 

Hunger, curiosity, or mistaken identity?

Attacks occur in many different ways. The majority of White shark attacks do not result in the death of the victim leaving researchers wondering why. Obviously a large Great white shark would have no trouble dispatching a human if that was its intent, but, in many cases the shark bites the victim once and then leaves. There are many theories as to why White sharks do this.

One theory is that the shark is simply using its sensitive taste, touch, and smell to attempt to identify the object in front of it. Unfortunately for the victim, this 'mouthing' can result in catastrophic injury. If the shark is indeed trying to ascertain  the victims content in order to decide whether it is worth eating, then its tendency to leave after the first experimental bite would imply that it finds human flesh either distasteful, or not fatty enough to waste precious energy trying to digest.

Another hypothesis is that the White shark is following its natural 'bite and bleed' instinct that it uses when tackling dangerous prey such as California sea lions. White sharks have repeatedly been documented to attack large seals explosively and then retire to a safe distance while the animal bleeds out. This strategy probably saves the shark from serious injury from the teeth and claws of the wounded prey. But, if this is the reason that humans are only bitten once and then abandoned, one wonders why the shark does not return before the individual is dragged from the water or manages to swim to safety.

Even if the extent of the injuries prove fatal the body of the victim is rarely consumed by the shark although this does happen. A snorkeller was killed in the Abrollos Islands off of the Western seaboard of Australia in March of 2005. The ferocity of the attack which was witnessed by other swimmers, indicated that the shark was single mindedly attempting to eat the victim and a cursory search for remains was almost immediately called off. At that time of year transient White sharks arrive from South Africa having spent many weeks crossing the open ocean where food is in limited supply. It is suspected that the resulting hunger of these sharks is such that they are likely to attack and consume what ever is available upon their arrival off the Australian coast.

Many attacks on swimmers occur in turbid water. This lends weight to the idea of mistaken identity i.e. the shark sees the moving light colored leg of the victim thrashing around in the surf and instinct kicks in. The shark expects a wounded fish and clamps down on the visible appendage only to find out that it is attached to a large struggling human. This mistaken identity scenario has also been attributed to attacks on surfers where the silhouette of the surfer on his/her board, when viewed from below, looks like the outline of a sea lion. In both of these instances, the shark which generally has excellent vision is made out be somewhat less intelligent than it probably deserves.

It may be that some shark bites are not food related at all. How better for a curious shark to explore its environment than to chomp down on an interesting object.

There are probably a multitude of correct reasons why sharks bite depending on circumstance. What really goes on in a sharks brain may never be truly understood.

 

The Shark Attack Capital of the World.

In the summer of 2003 a 'feeding frenzy' occurred in Florida. At the same time there were also a few shark attacks some of which tragically ended in fatalities. The 'frenzy' was a product of the media that was blown completely out of proportion. The coverage resulted in serious repercussions in the shark world. Although the amount of attacks was no greater than previous years, the media starved for real news, worked the attacks until politically motivated officials called for a ban on shark feeding in state waters. The bill was passed and the operators feeding nurse sharks around Boca Raton and other places suffered financially. Divers looking for their first shark interaction in the wild also suffered. The next year the attacks continued.

What is worth pointing out is that the fishing charters and pier fishers were still allowed to bait indiscriminately for sharks. The main beach attack grounds are surrounded by fishing piers where bait and fish scraps are tipped into the water mere yards from frolicking beachgoers. The nurse shark feeds took place way off shore and attracted sharks that have not been implicated in the Florida attacks and even if they were, their dentition would result in minor wounds compared to the reef sharks that were being fished off the beaches. Presently the dive operators negatively affected by the ban are lobbying for its removal but with limited funds at their disposal a return to shark diving in Florida is unlikely.

 

Caring for a shark attack victim

The following advice should be considered as pertinent to the care of a shark attack victim but not as a replacement for training in primary care. It is the responsibility of all of us to seek out basic medical training (which is available almost everywhere at little cost) in order to help others if and when a situation arises. The nature of shark diving has inherent risk which over time adds to the likelihood of injury and makes that need for medical training all the more useful.

 

There are many things that have to be addressed after an attack. Obviously, the first thing is the primary and secondary care of the victim if they have survived the initial encounter. Although the care will largely depend on the extent and type of the injuries there are things that are always required, for example shock management. Following is an outline of the order of primary care recognized by most training agencies. Outlines are just that, and can be deviated from whenever necessary. 

 

  • Firstly, assess the scene and isolate yourself and the victim from further harm. In a shark bite scenario this will probably involve getting everyone out of the water. It is tempting (for some people) to want to rush into the water and wrestle a victim from the jaws of a shark. While this may be the only choice, it would be prudent to look for a craft that will both protect you as a rescuer, and remove the victim sooner from the water. A surf board, small boat, jet ski, or even a life ring is better than nothing. The seconds lost in locating and pushing a 'float' into the water may be detrimental but may also save the victim by allowing blood loss management to take place sooner.

  • While this rescue is being attempted make sure someone has already been sent to contact the emergency medical services that are available in the local area. Your next actions are critically important but should be viewed as a link in a chain of care that should progress as quickly as possible to the next stage of professional care.

  • Secondly, once the victim is out of the water stem any bleeding. It is commonly taught that the monitoring of vital signs i.e. breathing and pulse are of primary concern but the extent of blood loss in attacks is often the cause of death so assessing this factor is critical. Often in attacks there is a large area of flesh removed which will sever blood vessels including arteries. Arterial flow of blood is easily recognized by the pulsing nature of the blood loss and the volume of blood escaping. Many attack victims bleed to death before anyone can reach them. A bite on the thigh (which is a common area of attack) can result in the cutting of the femoral artery which supplies blood to the legs and lower torso. The size of this artery combined with the blood pressure contained in the arterial system means that it is capable of discharging enough blood to kill the victim within minutes. Therefore it is important to know how to restrict the blood flow via pressure points that are at the base of the extremities. In the case of the femoral artery the pressure point is located close to the groin and involves compressing the artery against the femur (thigh bone). If you get this right you will notice a slackening or complete stop in the flow of blood. You can practice this skill by finding your pulse in your wrist and searching for the correct pressure point under your upper arm. Restricting this area should make your pulse go away (when practicing, only allow this to happen for a few seconds). Tourniquets are controversial due to the fact that completely restricting the blood flow to a limb may result in the loss of the limb from oxygen starvation but if the injuries are catastrophic involving a large amount of tissue loss then this may be the best defense against extreme blood loss while the rescuer takes care of other significant injuries.

  • Monitoring of vital signs is also critically important. If it is ascertained that a victim has stopped breathing or is in cardiac arrest, CPR must be started immediately and continued either until the patient can breath on their own or until rescue service personnel take over. When performing CPR it is wise to use a barrier if one is available. Wounds inflicted on the torso may complicate breathing problems such as punctures to the lungs, compression of the chest cavity, and broken ribs. In this case the best you can do is to make sure the victims airway is clear and continue CPR as well as possible.

  • Once it has been ascertained that the patient is not about to bleed to death and that vital signs are stable, it is important to monitor for shock. Shock is almost inevitable after a shark attack and can be just as life threatening as more obvious problems. The signs and symptoms of shock include an erratic or fast pulse, dizziness, incoherence or mental confusion, lethargy leading to unconsciousness, and in severe cases leading to death. Treatment includes keeping the patient warm, trying to keep them conscious, slightly elevating their feet (if they can lay on their backs) and closely monitoring pulse, breathing, and pupil dilation/ eye coordination.

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