More about Whale sharks

When I told people that I was coming to Mozambique to swim with whale sharks, most people reacted with some hesitation asking if I was crazy. Yes, whale sharks are the largest known sharks in the world, but they are also completely harmless to humans.

A confusing name, the whale shark is in fact a shark. It is the world's largest fish and grows to lengths of up to 20m. It has the characteristics of a shark in that it has a vertical tail fin that moves with a side-to-side action; it does not give birth to live young and instead houses hundreds of eggs inside the female until the young are about a foot and half long and can survive on their own; and they are cold blooded. However, in terms of their habits and size they are more similar to a whale. They are filter feeders which means that as they swim, they open their mouths to allow water to pass through their gills at which point they filter out all the zoo plankton. Yes, the largest fish in the world eats the smallest thing in the ocean. This means that the whale shark has to go where the zoo plankton is plentiful because it requires tons of zoo plankton a day to maintain its body mass. They are harmless creatures whose only self defence is its unbelievable size and incredibly thick skin on it's back. Their only predators are other large sharks and humans. Once a whale shark is fully grown, it is too big and it's skin too thick for any other shark to successfully eat it . What normally happens is that the great white comes up to take a bite and gets stuck on the whale shark as its teeth cannot fully penetrate the skin. The great white then needs to shake himself off the whale shark and both swim away. Boats, on the other hand, are a very different story. As the sharks generally feed near the surface and can be inquisitive creatures, it makes them highly susceptible to boat strikes. The propellers dig into the skin or fins and can cause great damage leaving injuries and scars.

As whale sharks only have a thin row of very small teeth, if a person were to happen to get caught in a whale sharks mouth, he would very kindly spit you out again as he has no interest in having you inside him. And, if while you are swimming with a whale shark, he gets aggravated by your presence, he banks away from you showing his back and dives down and swims away. If a whale sharks decides to swim, he may look like he's not going that fast, but it's impossible to keep up for very long.

Very little is known about these magnificent creatures. It has only been within the last 15-20 years that people have actively started to research their behaviours. One of the biggest research areas happens to be in Tofo, Mozambique. Here, at the Megafauna Marine Institute, they have been studying the whale shark trying to figure out what they do and where they go. On the skin of the shark, there is a series of spots and stripes which are unique to each individual. By photographing the sharks as they pass through Tofo, each can be identified and tracked as it moves around the world. What they've discovered is that the population around Tofo is mostly adolescent males. It's like the skateboard park, and fast food joint for whale sharks. They cruise through the area at about 5-10m long and then move somewhere else, where that might be, the researchers have no idea. They also have no idea where the females and babies spend time, nor do they know where mating or birthing takes place. In all the populations studied around the world, the females, babies and large males are not present which makes them wonder if maybe they live in the middle ocean during those stages of life. No one is really quite sure.

So, outside of simple curiosity and wanting to know more about the world we live in, why is it important to study whale sharks. Well, there is a growing problem of shark exploitation in the world, and whale sharks are not immune to it. With the increase of middle class China, the demand for shark fin soup is growing. Being able to serve shark fin soup to guests is a sign of prosperity in Chinese culture and there's a lot of prosperity happening in that country right now. So, why is shark fin soup so important? It's not really. Once upon a time there was a king who raved about how good shark fin soup was and well, if the king likes it, it must be good. It's really that simple. As a result, we are decimating our shark populations to fill the demand. Whale sharks being the biggest, their fins are worth the most money. They are used as displays in restaurant windows to entice people to enter. The rest of the shark is pretty much wasted as, on land, it weighs tons and is difficult to manage. As I write this, there are whale shark fisheries cropping up in China whose sole purpose is to catch whale sharks. This is incredibly dangerous to the whale shark population as they are long lived species. It takes a whale shark up to 30 years to reach sexual maturity and the majority of sharks being caught are teenagers. We are effectively destroying the reproducing population. If we are not careful, the whale shark might go the way of the humpback which had to struggle it's way back into existence.

The researchers in Tofo are doing their part to learn more about these animals and are working hard to establish the coast of Mozambique as a whale shark protected area. The problem is that Mozambique can only afford one coast guard boat. Even if they establish a marine park, there's very little hope that they'll be able to effectively patrol the area.

I feel extremely blessed that I had the opportunity to swim with these beautiful creatures and only hope that future generations will have the same opportunity.