Apex predators. Think of them and animals such as the Lion, Tiger, Wolf and Polar bear spring to mind. Given more thought, with some consideration of habitat, and you may also list the Jaguar from the Amazon rainforest or the monkey-eating Philippine eagle from the jungles of south-east Asia. Head to the ocean and everyone would shout 'Great white shark', 'Orca' or 'Sperm whale'. However, there are many others of course. Those less well known, species seldom seen and found only in the remotest regions, hold special allure. Like mythical beasts our knowledge of them is based less on fact and more on
legend. I place animals such as the Snow leopard from the Himalayas or the Eurasian lynx from the Taiga in this category.
From the open ocean I have another; the Mako shark.
Mako (Isurus oxyrinchus) - Photo by Pierre Couillaud
Blue sharks are the mainstay of our shark diving. It is easy to wax lyrical about their supine beauty, their supple movements mesmerise and lull your senses. You leave the water entralled but relaxed, your senses soothed like sore muscles feel after a skilled massage. However, chances are one in three that our shark dives receive a shocking jolt of electricity. A dive where you emerge from the water energised with pupils dilate and adrenaline throbbing through your limbs; a dive with a Mako.
When a Mako arrives it triggers a primeval response in everyone and in its presence every diver raises their game. Like a Blue shark on steroids the Mako's muscular form and movement provokes an instinctive response in our autonomic nervous system. There is no mistaking that this animal is a predator and one at the top of the table. Fortunately, neither the Mako or Blue sharks seem to regard divers as prey and, whilst inquisitive, they always disregard us in favour of the chum. With careful consideration and respect for these superb animals it is possible to dive with them safely.
Makos are beautiful and athletic fish. The colour of their skin has superb counter-shading. Their blue backs almost match the indigo hues of the Blue shark and constrast starkly with their metallic silver flanks and pure white undersides. Designed for speed (and capable of swimming +60km/h) their lunate tail flukes are near symmetrical (i.e. homocercal) and powered by formidable muscles that are clearly apparent in the laterally thickened caudal peduncle or tail stock. Short and stocky their body shape differs markedly from the slim, lithe form of the Blue shark. The head of a Mako also seems to hold more menace than a Blue shark. Makos have a short pointed snout, and rows of long needle-like teeth that are clearly visible even when they close their mouths. The eyes of the Mako also appear completely black and contrast markedly with the 'cat like' elliptical pupils of the Blue shark. With such soulless eyes to me the Mako is the ocean's 'Prince of darkness'.
Makos are long lived (up to 30 years), slow to mature animals (50% males mature at 8 years, 50% females mature at 18 years). Males therefore mature at a smaller size than females (1.85m for males, 2.75m for females). They are ovoviviparous. Females produce live young but rarely more than 10 at a time and infrequently, perhaps once every 18 months. They therefore have a low reproductve rate and their populations are consequently vulnerable to direct fishing or by-catch in the tuna and swordfish industries.
We know remarkable little about these sharks in the Azores. Makos are sometimes sought by big game fishermen and it is known that some parts of the archipelago are better than others for finding them. Diving with these sharks may actually help improve our knowledge. As divers we can record where and when we see Makos. We can also record their numbers, sex and size as well as any distinguishing marks that may help us identify individuals in the future. By recording these data we can gather more clues to help solve the mysteries of their lives. Information that ultimately could help protect, manage and conserve their presence around the archipelago and secure their future.