In a little over 50 years, the systematic global slaughter of sharks has risen dramatically; by 400 per cent to approx. 800,000 metric tons per year - and this is only the recorded catches, many are not reported and the actual annual amount is in all likelihood much higher.
Phil: "We are systematically eliminating large predators such as Swordfish, Tuna and Shark from our planet. In the current generations lifetime - say 20 or 30 years, they may all disappear due to destructive fishing practices and the consuming greed of humans. Meaning they will be Extinct - gone forever. There will be no coming back from this, it will have disastrous consequences for ecosystems and of course we have no idea what kind of effect this will have for us in the future."
Sharks have roamed our seas as apex predators for over 400 million years, and throughout this time they have become immensely well adapted to their respective environments. The term Apex predator means that they prey on other creatures beneath them in the food chain for their survival, and sit right at the top (or apex) of this intricate energy web.
Due to this Sharks play an extremely important role within marine ecosystems; they are essential to the health of the oceans, driving evolution in fish species through predation, regulating fish, squid, pinniped and crustacean populations, and removing diseased and less viable animals from ecosystems.
In short; Sharks maintain the critical balance of the oceans and have done so longer than any other Apex predator our planet has EVER seen.
Eliminating sharks from ocean systems has disastrous effects, including the degradation of coral reefs and the collapse of commercial fisheries. Ecosystems with healthy shark populations actually have higher numbers of fish than those with unnaturally low shark populations; though it may seem counter intuitive for a large predator to increase numbers of fish, this happens because of the complex way sharks maintain the balance between different species.
One of the things that is often overlooked by consumers is that sharks reproduce differently to other fish and cannot be caught at the same rates as other species without serious ramifications. Rather than laying thousands or millions of eggs as most other fish do, many shark species are extremely slow to mature and can take up to fifteen/twenty years to reach sexual maturity, and often then only produce one or two pups per year, with long gaps (often 3-5 years - or much longer in Deep sea sharks) between mating.
Such a fragile and slow reproduction rate in many species means that their populations are especially sensitive to disturbances such as over fishing and at the current rate of removal and consumption simply will not survive.
We have had sharks in the oceans for over 450 million years, and they have survived all five of the mass extinction events that have occurred during this time, some of which wiped over 95% of all species off the face of the earth! To put this into some perspective; Dinosaurs appeared around 230 million years ago, and subsequently became extinct in one of these events, and Hominids (Human-type animals) evolved 4.5 million years ago.
So not only have sharks been around 100 times longer than us, they massively outlived the Dinosaurs and even existed before the evolution of land plants and trees! In fact we even share a common ancestry with sharks; Our evolution from the oceans means that we have developed certain characteristics that originated in sharks and fish, our jaws and the muscles surrounding it that enable us to speak and chew, as well as small bones in our ears that enable us to hear, all evolved from the primitive gill arches in fish, and our top lip, jaw and palate all start life as gill-like structures on our necks in the womb.
Although they can differ dramatically in appearance and size, (the smallest shark is the Pigmy Lantern shark 8.3 inches - to the biggest, the Whale shark 17 meters) all sharks share a few essential biological traits. For example sharks do not have a single bone in their bodies; their skeleton is made from cartilage, and they all share similar sensory organs. There are currently over 500 known species of shark, 600 species of skate and ray and 30 Chimaera - all of which belong to the class Chonrichthyans (cartilaginous fishes).
Most shark species have between 5-15 rows of teeth and in fact you can really see the difference between shark species when you look at the design of their teeth, each species; depending on the environment they inhabit and the type of prey they consume has a tooth specifically designed for the job. These are very distinct, for example Great White sharks have large triangular teeth with serrated edges for tearing large chunks of flesh, where as Mako sharks have very pointed teeth for piercing and trapping fish.
The skin of a shark is covered with tiny teeth called dermal denticles (or placoid scales) These are covered in hard enamel and as the shark grows these fall out and are replaced with new ones. They function defensively to protect the shark but also reduce drag making the shark more efficient as it travels in the water. What is fascinating about these scales is that many scientists believe the teeth of a shark evolved directly from them....as sharks teeth are similar in composition and shape, and like the scales fall out to be replaced on a conveyer-belt type system.
Sharks have highly developed senses - in fact they have SEVEN of them! thats two more than we have. Not only this, but the senses that we do have in common are far more developed. Sharks possess a reflective layer behind their retina called a Apetum Lucidium which allows them to see in dark environments, meaning that their eyes are ten times more sensitive to light than ours.
Two thirds of the total weight of a sharks brain is made up of olfactory lobes, which allow it to analyse smell directionally; they can detect one part of blood to one million parts of water, equivalent to one teaspoon of blood in a swimming pool. Sharks also have very acute hearing and are particularly sensitive to the low frequency sounds associated with wounded prey or sporadic swimming. Their sense of touch is heightened by the fact that sharks have multiple nerve endings beneath their denticles and in their teeth which they use to identify objects with 'test' bites.
However it is the two extra senses that a shark possess which are by far the most impressive. Sharks are able to detect changes in water pressure through a system of fluid filled canals that run down the side of a sharks body - known as the Lateral line. Any variations in the water around the shark are detected through ripples in the water made by displacement or pressure; they can quite literally sense the presence of other fish around them.
Finally (and most interestingly) sharks are able to detect electrical currents! They have an extraordinary electrosensory system, comprising of jelly-filled pores on the snout and head called the Ampullae of Lorenzini which enable the shark to detect changes in the Earths geomagnetic field or the electrical currents given off by all living things such as a muscle movement or a heartbeat
But as we have already established – sharks are not senseless killers, they are in fact very sensitive and very susceptible to exploitation.....they definitely have more to fear from us, so why exactly are they so feared? What is it about sharks that terrifies people?
Extract from Truo world aims day film by Phil Knox of Purple Flame Media.
Jaws quickly made its way in to the public concious, and the tension present in the film means that to this day it is still considered one of the ultimate horror movies. The tag line “Don't go in the water" from the movie struck such a cord that it radically changed how people perceived (and continue to perceive) sharks and inadvertently turned out to be the biggest anti shark PR campaign ever. The “revenge seeking shark” effect was such that Shark numbers worldwide have been effected due partly to the frightening and false ideas the film helped spread about them, and partly due to the thousands of shark fishing tournaments and revenge killings that popped up in its aftermath.
The film did have other effects however, it was never intended by the writer or director to be detrimental to the species; In fact Peter Bletchley the author of the novel that inspired the film spent much of his life after its release working to un-do the damage caused and promote shark conservation.
For many the movie has spawned a lifelong passion for the predator, and it has inspired a new generation of shark enthusiasts and scientists from around the world; all fascinated and excited by sharks and the idea of understanding and studying their anatomy and behaviour. The same can be said for conservationists, many of whom saw the film and fell in love with sharks – researching and campaigning to change the much maligned attitude of the shark as a killer.
We know that sharks are not capable of the 'Revenge' style attacks that occur in the film Jaws but we also know that shark attacks do happen – however these are extremely rare and are often blown way out of proportion by the media who thrive on spreading fear and anger in an effort to sell stories.
Fatal attacks on humans by sharks unfortunately do happen; it is foolish to ignore the fact that these animals are predators after all, but fortunately these are incredibly rare and are often the result of simply being in the wrong place at the wrong time.
Humans are not food for sharks, we are not part of the ocean food chain – The Great White shark for example favours blubber rich seals/whales while some species like Tiger sharks prefer Turtles and other sharks such as Makos predominantly eat fish. Many species are however opportunists and have been known to 'feed' on shipwrecked or floating bodies, but for the most part when a shark actually attacks it is not doing so to eat us but rather to find out what we are.
Often once the shark has tested its intended prey and discovered it to be human not a tasty seal; the shark releases and looses interest. Many deaths from shark encounters occur due to blood loss as this test bite severs an artery or causes the victim to go into shock. Very few people have been intentionally the prey of sharks and even fewer have been devoured by them.
In 1963 off of Aldinga Beach, 50km south of Adelaide Rodney Fox was bitten by a Great White shark across his chest whilst spear fishing in murky water - often the smell of speared fish attracts sharks, and can cause them to go into attack mode. He was very lucky to survive.
In total, Rodney had 462 stitches in his chest, and 92 in his right hand and arm. From the extent of the wounds the fact that he survived is amazing. What is even more amazing is that a year later he was back in the sea, and even invented the first ever shark cage.
Rodney became fascinated by sharks and has built a career out of cage diving, his company - the first operating in Australia, not only worked on expeditions where Great White sharks were filmed for the first time, but he also helped produce the underwater footage used in Jaws. Rodney has never blamed the shark that bit him, but has turned a near-fatal incident into a life of discovery, ingenuity and passion. http://www.rodneyfox.com.au
In 2014 only 3 people were known to have been killed by sharks!
Chairs on the other hand killed approx. 700 people around the world!