DIVING WITH THE SOLITARY AND OPPORTUNISTIC LONGIMANUS
The oceanic whitetip shark (Carcharhinus longimanus) is one of the most common predators in the open waters of all intertropical areas of the oceans. It is considered one of the most common and truly oceanic sharks of its species.
Although this species is currently classified as vulnerable in the Red List of Threatened Species of the International Union for Conservation of Nature, it is still quite abundant, moreover, the whitetip was one of the first to appear, also in large numbers (something strange because of its characteristic of solitary shark), in the disasters that happened in the middle of the ocean, such as torpedoed ships or downed planes during the two world wars, something very unfortunate for the victims who were left floating in the water.
SOME OF THEIR BIOLOGY
They are not very large sharks, it is rare for them to exceed 3 m in length, females being larger than males. Adults are usually gray-bronze above and white below with a discreet white band on the flank, although variations of the color can appear towards brown and lighter shades on the back.
Something very characteristic of these sharks is that they have very visible white spots on the tips of the pectoral fins, on the first dorsal, pelvic and caudal fins. Their common name totally honors these spots. Continuing with its fins, the dorsal and pectoral fins, especially the latter, are very large and with a widely rounded margin. This is also the origin of its scientific name: Logimanus.
The body is large and robust, its snout is short and blunt, the eyes are small and round, with nictitating membranes. The upper teeth are large, with a wide base and triangular cusps, and the lower teeth have a wide base and narrow cusps, with strongly serrated edges.
Their reproductive habits are very similar to the rest of the other species of sharks, being easy to observe scars on the backs and tails of females caused by the male, as they bite the female during mating. The gestation of the young lasts about 12 months and they develop in the mother's cloaca inside a placenta. The number of specimens per litter varies from one specimen to as many as ten.
A DIVE IN BROTHERS
At the end of last year I was invited on a Borthers cruise to collaborate in a Shark Project led by Dr. Elke Bojanovski. The renowned biologist and expert on these sharks wanted to photograph as many specimens as possible to increase her archive and I was there to help her.
In each briefing, Elke repeated the basic safety rules, rules that I always repeat in each of my trips when we dive with "somewhat special" sharks: do not separate, keep an eye on each other's back, keep eye contact with the sharks, avoid sudden movements, stay as short as possible on the surface avoiding splashing and agitation and be very relaxed and calm during the dive, the most important thing in diving with sharks is... to enjoy them.
Longimanus sharks sometimes come close to the reefs to hunt, but they are pelagic animals, their life takes place in the open sea, so to see them you have to move away from the coral walls and look for the line formed by the moorings of the boats, or even go a little further into the blue. There were times when there were as many as fourteen boats moored at Big Brother, everything was full of lines everywhere.
We set our own course, passing the capes of all the boats between twelve and fifteen meters deep. They usually come and go always on the same line, they have a fixed route that they repeat endlessly. Diving with Longimanus is not a reef dive in some occasions, you move in a short distance and it goes very slowly, in fact we were looking for their steps and we waited for them almost static, between two waters, helped by a fantastic visibility of more than thirty meters. That same visibility allowed me to witness their curiosity. It happened one morning when an inflatable boat stopped above our heads. Immediately, a shark that was passing by us, attracted by the noise, climbed up vertically and began to hover around the propeller that was idling. It stayed there, circling near the surface, until the boat left.
Sometimes we would get in the middle of its imaginary line, which is not very advisable because they do not like to vary their trajectory, and we would stand still watching it come. The shark would dodge us at the last moment, but you could see its displeasure because when it was almost parallel to us it would make a sudden and accelerated approach, a quick feint that would put it at a distance of two meters and that we had to endure with a certain cold blood, but in the end, as it is clear that we are not its prey, it would continue on its way.
But it is not always easy to remain unchanged. In one of the dives we were at about fifteen meters and a Longimanus appeared and was curious around us. It was about two meters long, not one of the biggest, but it made a beautiful picture because it was accompanied by half a dozen black and white pilot fish. He made a couple of slow laps around the group, and on the third one he showed more interest in a girl wearing white fins.
El caso es que la chica, al ver que el tiburón se fijaba en ella, empezó a ponerse nerviosa, a respirar más deprisa, a nadar más rápido, justo lo que no se debe hacer cuando te ronda un tiburón curioso, y sobre todo un Longimanus, que tiende a contagiarse de los nervios de los buceadores. Ya he dicho antes que se me han acercado a un palmo de distancia, que se han quedado casi estáticos a mi lado, observándome, sin hacerme absolutamente nada, pero aquella chica no paraba de bracear y de mover las aletas, y el Longimanus empezó a darle pasadas cada vez más frecuentes, acelerando y frenando de golpe, hostigándola. La chica, lejos de relajarse, se agitó aún más, y el tiburón, claramente excitado, la golpeó con la aleta en una de sus pasadas. La situación se puso realmente peligrosa, el escualo se movía cada vez más deprisa, yendo y viniendo entre el grupo de buceadores, pero las aproximaciones se las reservaba a la buceadora de las aletas blancas. La chica empezó a jadear y a agitarse cada vez más. Con flotabilidad ya muy negativa, pataleaba sin parar para evitar bajar más metros, no había nada más que pudiera hacer para indicarle al tiburón que era una presa perfecta. Por fortuna, Elke se dio cuenta de un cambio radical en la actitud del tiburón, su siguiente aproximación ya no sería de tanteo, había plegado las aletas quizás para iniciar un ataque.
Todo lo que he contado sucedió en segundos. Por suerte Elke estaba cerca e intervino, se cruzó por delante de la trayectoria del tiburón, que se vio forzado a girar, agarró a la buceadora de la grifería de la botella y la metió en medio de grupo antes de encararse a ella para tranquilizarla. El tiburón dio una vuelta más al grupo y se alejó. Yo pude grabar todo con mi cámara para luego más tarde estudiar con Elke, y con aquella chica, la acción sucedida.
With my articles, lectures and courses, I try to protect sharks and wash their image to present them as the fascinating animals they are, over those who portray them as man-eaters. But at the same time I want to make it very clear that diving with some sharks without knowing, carries a high risk. I have been diving with them for 30 years and I have never felt in danger, but I am always vigilant. You have to pay attention to the indications of the experts and do not ignore the safety rules because if you are careless, especially with some species of sharks, they can do a lot of damage or even kill you. In the water they are always the masters...
Let's dive with sharks, yes, without a doubt, but knowing how to do it.
