Historically, there is little that incites fear into beach-goers hearts more than a shark fin breaking the surface. The increase in recreational swimming and ocean sports, like surfing increase the risk of shark attacks. Shark attacks have caused much retaliation from local and national populations. The shark attack prevention techniques featured in this article are generally considered indiscriminate or primitive, killing sharks (known for attacks or not) and a plethora of other marine organisms including turtles and dolphins. According to National Geographic in 2011 only 12 people were killed globally, with other sources claiming that 11600 sharks are killed on average per hour. There are believed to be three shark species that are most known to attack humans: The Great White (Carchardon carcharias), the Tiger (Galeocerdo cuvier) and the Bull shark (Carcharinus leucas). The Bull shark is unique in it’s ability to survive both in ocean water and freshwater, pupping upstream and is also known for actively hunting up river. This adaptation of the Bull shark limits the successful use of any oceanic shark prevention methods and attacks have occurred in rivers.

 

Galecerdo cuvier(commons.wikimedia.org)

 

 

Carchardon carcharias (commons.wikimedia.org)

 

 

Carcharhinus leucas          (flickr.com)

Reportedly the worst case of mass shark attacks ever known were during the return journey of the USS Indianapolis. The USS Indianapolis, having successfully delivered components of the nuclear bomb that was later drop on Hiroshima, Japan- was torpedoed by a Japanese submarine. The Sinking of the USS Indianapolis took less than 12 minutes and left only 316 of the original 1196 United States sailors alive. The majority of those lost are believed to have been victims of either subsequent exposure, drownings or shark attacks.

 

 

Culling-

This is usually the technique that is used immediately after a string of localized shark attacks. The local population requires action and the best assurance that attacks will not re-occur. Large quantities of sharks are indiscriminately hunted and killed, rarely ever claiming the life of the original perpetrator(s). Even to this day naïve beach goers believe the sea and sand along coastlines is property of mankind, demand culling like peasants from Mary Shelley’s “Frankenstein” baying for blood, who do not understand the impact a cull would have upon the marine ecosystem. Removing an ecosystem’s apex predator has dire impact throughout the entire system. This brutal “shark attack prevention” method has high levels of failure, not just to marine ecosystem but to the people who demand protection. Culling is nothing more than a knee-jerk reaction to a tragic occasion, not preventing any attacks but exacting a heavy dose of revenge. This method is no longer considered viable by many as it dramatically reduces shark population numbers making it difficult to re-populate the area.

Drum-lines

A Drum line is a prevention method which implements large baited shark hooks, anchored to the seafloor and attached to a drum/ buoy at the surface. Considered to be a more selective approach towards shark attack prevention than culling and shark nets, Shark Drum-lines only affect a limited area.  Drum-lines are used to draw a local shark to the baited hook, drowned by the anchored hook. Believed to be much more effective at limiting the three main shark species known for attacks, in a very limited area. However, it has been argued that baiting numbers of hooks could draw more sharks into the area and actually increase the risk to humans, therefore requiring the additional use of static nets.

 

Shark net

Shark nets have been widely used for decades (Australia, U.S.A & South Africa) and have shown great success in reducing attacks. Shark nets placed off-shore along popular beaches can completely eliminate any shark activity within the protected zone. However, there are several downsides to using shark nets. Firstly, the indiscriminate slaughter of many marine species, from sharks, dolphins, seals, fish with even seabirds not being immune to becoming entangled in netting and death by drowning. Sharks have also been known to enter protected areas by avoiding the net or using damaged areas to entire the protected zones, rendering the prevention method less than useless, where inadequately monitored and maintained.

 

A variant of shark nets known as a “shark grid” used large gauge steel wire to create a barrier between sharks and people visiting popular beach sites at safe distance; again the shark attacks were greatly reduced in a localised area but problems occurred when the shark grids suffered breakage or malfunction due to lack of sufficient maintenance.  A further disadvantage to shark grids was the high cost compared to shark nets (which are generally made of either nylon or plastic).

 

Conclusion

As we destroy and remove habitats and food sources, sharks nevertheless still need to eat. But does that mean that sharks, or more precisely the known “villain” species, now consider humans as a prime and easy source of food? The evidence says not – most shark attacks are single bite or “raking” and most individuals survive. Instances of individuals actually being eaten are very rare. Sharks are known to be curious and investigate by using their mouths, so most attacks involve a single bite and the victim then being quickly released. The fact is that sharks evolved much earlier than man, in which time they evolved well defined eating habits – frankly, we are probably not to their taste

The methods listed in this article are still widely implemented today, however there have been many new methods and even technology improved versions of those above. All the methods named above were widely used throughout the 20th century and are common emergency measures used today. The main difference between the use of these methods presently and in the past is that historically there was no relocation or effort used to free the marine organisms caught.
There will always be human and shark interaction, no matter how hard we try to control and protect ourselves – no one method is a complete preventative. With the increasing popularity of open ocean and coastal watersports there is an inevitability of shark attacks on humans. Maybe a combination of several prevention methods is the key to reducing shark attacks on humans. Or, should we change how we use the sea recreationally ?

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