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World Shark Day

World Shark Day

Posted: 13 Jul 2020

Savage, monstrous, evil-looking, nightmarish, ferocious, unromantic, man-eating machines. These are just a few examples of how the media portray sharks and are the kind of words that spring to mind when people think of sharks. But sharks are incredibly misunderstood creatures - did you know there are over 500 species of shark and only 3 of these species are really deemed to be dangerous to humans?  

 

The South African coastline is home to over 100 of these species. When people think of sharks, they think of the big ferocious great white shark or tiger shark, but we have a number of cute harmless species around our coastline. Some of the most common species you might see are: 

 

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Pyjama Catshark Dark Shyshark Leopard Catshark

 

All of these species are bottom dwellers that can be found in the kelp beds around the Western Cape and other parts of our coastline. They are endemic to South Africa, meaning that they are not found anywhere else in the world. These sharks are all known as ‘shysharks’ because when they are scared they roll themselves into a donut, put their tail over their eyes and hide from the world. Does that seem ferocious to you?  

 

greatwhiteshark

Great White Shark

 

Even the species that are thought to be ferocious such as tiger sharks, bull sharks and great white sharks, are not the aggressive animals they are believed to be. Yes they are curious, yes attacks do happen but 99% of attacks that occur are a result of mistaking us for their prey or from a curiosity bite. We know this because these sharks will often bite a human and then leave, realising the human is not their prey. Sharks do not have hands to feel, they determine what something is through a ‘curiosity bite’. Sadly their bites are often fatal to humans due to their large size, but the important point is that sharks are not out to get us! We have many of these dangerous sharks around South Africa and many people swimming in the ocean on a daily basis. If these sharks were the man-eating machines that people believed them to be, we would likely be seeing an attack happening everyday.  

Even though sharks have a bad rep, they are actually awesome animals that have been around for millions of years.

 

Here are some cool facts about sharks, that may surprise you: 

 

  1. Sharks do not have any bones! Sharks have a cartilaginous skeleton. Cartilage is the clear gristly stuff that your ears and nose tip are made of. Cartilage is much lighter than bone so their skeleton helps them stay buoyant, move quickly through the water and gives them increased flexibility.  
  2. Shark skin feels similar to sandpaper! Their skin is made up of lots of tiny teeth called denticles. When touching a shark, their skin feels smooth in one direction, and like sandpaper in the other direction! Back in the day they would use shark skin as sandpaper. 
  3. Sharks have a sixth sense! All sharks have a 'sixth sense' that helps them hone in on prey during the final phase of attack: the ‘amupllae of lorenzini’ are found on sharks' snouts, they look like black heads, and they use these to sense the electric fields emitted by animals in the surrounding water. This is why people say that sharks can hear your heart beat – it is true! 
  4. Sharks are one of the oldest animals on the planet! Sharks have been around for over 400 million years - long before dinosaurs. They have survived multiple extinctions and are one of the oldest vertebrates on the planet.  
  5. Sharks are really slow growing animals! Most sharks are very slow growing, with a late age of maturity and long pregnancies. Great white sharks for example, take 20-30 years to become sexually mature. When they do have young they are pregnant for 14-18 months and only give birth to a maximum of 2-10 pups at one time. Other species like a spiny dogfish shark are pregnant for up to two years!  
  6. Sharks lay eggs but also give birth to live young too! Some species of sharks lay eggs (called mermaids purses that you will often find on the beach), whilst others give birth to live young – just like mammals. 
  7. Shark embryos eat each other in the womb! In some species of shark that give birth to live young, the largest embryo is known to eat its fellow embryos in the womb, in an act known as intrauterine cannibalism.  
  8. Some female sharks can reproduce without male sharks! Female blue sharks have been known to clone themselves in the absence of males. This has also been observed in a Zebra shark in an Australian aquarium. A female called Leonie, gave birth to three pups even though she had been separated from her mate.  
  9. Sharks are less dangerous than hippos, lightning strikes and vending machines! It is seriously unlikely that you will get attacked by a shark. On average there are about 5-10 fatal shark attacks worldwide per year. Hippos kill an average of 2900 people annually, lightning strikes kill around 2000 people per year and vending machines around 80 people per year! Watch out for those vending machines…! 
  10. 100 million sharks are killed every year! Shark numbers are declining worldwide due to shark fishing becoming more and more popular over the last 20 or so years. A dish called ‘shark fin soup’ is largely responsible for the demand for shark as well as an increased demand for shark meat. Shark fin soup is a delicacy in Asian countries, and especially in China. As indicated by the name the soup involves using the shark fin. This has resulted in the deveopment of an incredibly unethical and inhumane shark fishing practice called ‘shark finning’, whereby fishermen will catch a shark, cut it’s fins off and throw the shark back to suffocate and bleed to death. This allowed fishermen to maximise the amount of fins they obtained. Thankfully, this practice is now illegal in most countries but there is still illegal fishing going on. Here in South Africa we have a large shark fishery that is actually more focused on the shark meat. Hundreds and thousands of sharks are caught here and exported to Australia, where the meat is sold in fish and chip shops as ‘flake and chips’. 

 

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Dark Shyshark Shark skin under a microscope

 

The bad reputation that sharks have is sadly a huge impediment to their conservation. Shark numbers are declining everywhere and because many people believe they are man-eating machines, many people do not care. But did you know that sharks are crucial to the survival of our oceans? Studies have shown that declines in shark numbers have resulted in the collapse of whole ocean ecosystems. Sharks are top of the food chain and keep everything in balance and in check, so if we lose our sharks, inevitably our marine ecosystems will break down, and that is just shooting ourselves in the foot! As not only do we depend on the oceans for food and resources, but we also depend on the oceans for over 60% of the oxygen we breathe.

 

So, protecting our oceans is protecting ourselves and a huge part of that is protecting sharks because healthy oceans NEED sharks, it is particularly important! 

 

Mary Rowlinson
Marine Biologist and Manager at the Shark and Marine Research Institute in Gansbaai

 

Click here to enter our Shark Day competition on Facebook before the 24th July 2020.

You could win a beautiful hamper filled with arts and crafts to the value of R600 sponsored by Screenshopping.


A little about Mary Rowlinson: 

She was born in the UK and always had a passion for sharks. She completed an undergraduate degree in Zoology and moved to South Africa to follow her passion for sharks and studied for her Master’s in Marine Science at UCT. She has been working and studying sharks in Gansbaai since 2016 and is passionately involved in the conservation of the sharks that we have left. 

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