The game of … Who’s Who?

There is a lot of talk about how dangerous sharks are, but they are the ones on the verge of extinction due to the direct action of human beings.

I would like to introduce you to them…

Have you ever noticed that big animals have very small eyes? Do they really have small eyes or in the immensity of the animal they seem small? I have always been impressed by the eyes of the shark. Those eyes that always look into the void. Dark as the depths of the sea, what is behind these gazes? Sharks are almost blind but they compensate with a system of pores on their head and snout, called ampullae of Lorenzini, which allows them to detect electrical signals emitted by other animals. This sense of electro-reception allows them to perceive the heartbeat of another fish at a distance of one metre, they can detect electrical currents lower than that produced by a small battery and recognise the state of their prey’s heart, and even locate them, even if they are buried in the sand.  In addition, the vast majority of sharks have a line of blisters along their sides filled with a gelatinous substance that allows them to detect any movement around them, even at a distance of tens of metres. It is impossible to get close to a shark without it knowing it.

They are also considered to have highly developed senses of smell and taste. As for their sense of smell, they are able to detect the smell of a drop of tuna blood in tons of water. They can even locate the scent several tens of kilometres away. Their immune system protects them from almost anything, being able to regenerate and heal themselves.

It seems incredible that they were once thought to be antiquated organisms due to a lack of evolution!  But, finally it was concluded that they did not need to modify anything because they were already perfect and that was the reason for their evolutionary immobility. And I’ll tell you a secret, these sensory organs are the envy of science!

Scattered throughout the world’s seas and oceans there are more than 540 species of sharks. But today we are going to dive into the water to talk about one species in particular, as this winter some specimens have been spotted between Ibiza and Formentera. We are talking about the blue shark, also known as the big blue shark (Prionace glauca). A very cosmopolitan shark that can be found in all the oceans and seas of the world, occupying both the surface of the open sea and coastal areas with cold waters of between 7 and 16 degrees Celsius.

With their particular skin colour, they are experts in camouflage: their back and sides are an intense metallic blue colour, while their belly is a well-defined white. They have a slender, elongated body with a long, conical snout. They are approximately 2.5 metres long and weigh up to 80 kilos. A singularity of this species is that, due to the length of its nose, its jaw has had to adapt to be able to bite without problems, as the upper part of the jaw is able to project forward, so that to bite it does not need to raise its head and when its teeth fall out, they are replaced by triangular-shaped teeth with serrated edges. On warm days, blue sharks often come close to the shore for the enjoyment of us divers.

While we’re on the subject of diving… Where was my first shark experience? Guess where in some beautiful sea of the world? No!!!! Let me tell you.

My parents were on holiday for the first time in Spain and I was living in Barcelona at the time. You can imagine that it was a dream holiday, so eager to see everything, every day we proposed different routes and excursions to get to know this beautiful city. Walking around the Barceloneta area we came across L’Aquarium de Barcelona. It seemed like a good plan and we went in to see it. I was pleasantly surprised when we were informed that divers with a valid diving licence had the opportunity to experience the experience of diving in the main tank and dive surrounded by fish. We signed up for the next day.

We arrived early in the morning. We were given a short talk about sharks, their behaviour and what your attitude should be towards them. Once we were fully equipped, we entered a small pool where I was able to take some photos and say goodbye to my companions who would follow my adventure from the other side of the glass. Next, I entered a series of tunnels that led me to “The Pool”. And there I was, in a tank with 4 million litres of water and more than 5000 organisms, such as moray eels, groupers, rays, conger eels, it was fascinating the amount of colours that danced around me. My dive was slow, measured, I wanted the time not to pass, I enjoyed it, and at that precise moment, I found myself face to face with a bull shark. Oh oh! So many sensations, fear, nerves, enthusiasm, excitement and admiration! An image to treasure and that my parents from the other side of the glass were able to capture with their camera.

It was a unique experience with mixed feelings. On the one hand, the beautiful experience of having shared diving with them and on the other hand, having them in captivity. It is a feeling of sadness that is relieved to know that they were rescued from the sea and survived serious injuries. If they were to return to their habitat in the wild, their physical limitations would lead them to certain death.

You know the answer, my first dive with sharks was in an aquarium!!!!

Since then, I choose to dive with them in the open sea. I have traveled to dozens of places: Thailand, Indonesia, Maldives, Cuba, among many other places. I was lucky enough to see different species such as blue sharks, hammerheads, lemon sharks, white tips, black tips, nurse sharks, bull sharks… It is a unique and incomparable sensation, floating in the depths of the sea and seeing their silhouettes, surrounding you, making you feel small, at their mercy, until you become part of them. Incredibly exciting!

But beyond particular experiences, there is a big concern: their existence and how to protect them. Sharks are essential to marine ecosystems because, among other things, they are responsible for the population balance of their food species and keep the oceans clean by removing diseased animals. However, they are vulnerable due to their small numbers of young, slow sexual maturation and reproductive cycles of up to 22 months, coupled with scarcity of prey, pollution, habitat destruction and the cruel practice of shark finning.

For example, the Atlantic dusky shark does not reproduce until it reaches maturity after 20 years of growth. Spiny dogfish gestate for almost two years and bull sharks have only two pups at a time. The reality is that shark populations cannot reproduce at the rate at which they are being exploited and there is irrefutable evidence that sharks are already disappearing at an unprecedented rate worldwide.

As for finning, it is a ruthless practice, which cuts off the shark’s fin and discards the rest of its body (although finning is not banned in the European Union, fishermen are obliged to keep and use the whole body of the animal). The fin is a highly prized food in Asia, mainly for making soup, a dish considered a delicacy.

The cruel business of “finning” and indiscriminate shark fishing by many countries (including Spain) must be stopped. This type of fishing is wiping out shark populations. If we do not stop this crime spree, very soon, perhaps in a few decades, we will lose the shark, a creature that has survived for more than 400 million years, resisting the climatic impact that caused the extinction of the dinosaurs and that today, because of human greed, we are bringing to the brink of extinction.

How can we help protect them?
Although it is not an easy task, we can all do our bit by taking the following actions:

  • Don’t order shark fin soup. Besides being a totally tasteless soup, it is totally false that it gives more sexual vigour.
  • Do not eat shark meat.
  • Raise awareness and let our community know that endangered sharks are being fished in many countries.
  • Encourage divers to meet sharks and to dive with them. Increased revenue from the dive tourism sector can help governments understand that live sharks can be a major tourist attraction and should be protected.
  • Inform the general public that sharks are not human killers, but the opposite.
  • Collaborate with shark protection projects such as the “Stop Finning” – https://www.stop-finning-eu.org/es/

That is why it is important that: 

Observe the oceans, fix your gaze on the sea, feel it, breathe … they provide us with half the oxygen we breathe … where legends come to life and reality becomes a fable. Unknown worlds, unknown stories, only guarded by a raging and defenseless sea. 

 Carla Villari 

References: 

Wikipedia.
Karlossimon.com
Anchor
Buceo Ibérico.com 

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