The best studies of wild animals are those in which the ethologist researcher manages to be accepted into the animal community. This is something that only happens when the animals in question facilitate the meeting, so it was the last thing I expected to happen with sharks. Indeed, it had been assumed to be impossible to achieve in the case of this ancient line of animals. But with blackfin reef sharks, patience was rewarded.
Even in the beginning, when I first began to seek them out in the lagoons of Tahiti, the responses of many of the shark individuals I met were fascinating and informative. On one occasion, I was exploring when I had the strong sensation that someone was watching me, and thinking that an outrigger canoe had glided near, I put my head above the water. But the surface was empty in all directions. When I sank again, I was face to face with a shark; as soon as I looked at her, she turned and departed.
Sharks will often come close for a look when a person has their head above the surface—they know when you can see them, and when you cannot.
On another occasion, I was able to accompany a female blackfin shark for more than half an hour as she travelled along the reef, though we had never met before. The only sign of her concern was that every so often she would suddenly turn at right angles across my path. Sharks will do this when they are uncomfortable about the situation. But each time she turned, I stopped moving, and each time, we went on.
It was soon after this that I began taking a few fish scraps to the lagoon. The food did rivet the attention of the resident sharks, but it took many such visits before they would eat in my presence. Initially the food caused them to look more closely at me, but they circled through the surroundings until I left--they were waiting for me to go. But eventually the food I brought, weekly, won their trust, and I was able to observe their intimate behaviour.
For the eighth session, the scraps had been frozen and I tried to thaw them as I paddled my kayak out to the study area near the reef, which took about forty minutes, depending on the wind. Madonna, (shark #1), was waiting when I slid underwater with the food still frozen. I was sure that it would swiftly thaw in the warm water, however, and tried to separate the pieces while she circled me. There were two small bags of scraps, one of white meat, one of red. The scraps of white meat came apart, but not the bloody red scraps, and naturally it was this chunk of frozen meat that interested the shark.
I decided on the spot to drop it as she approached, and while she investigated, I swam down to take her photograph. Then she took hold of the frozen chunk and gave it a shake. Failing to extract the expected bite, she circled again, chose a piece of white meat, and ate it. Then Bratworst (Shark #2), who had already distinguished herself as a curious shark, swept in, and Madonna sped up. The two soared around the area, and on returning, Madonna grabbed up the bloody mass of frozen fish and whipped it back and forth, her head and tail nearly touching with each swing. She charged upward and through the surface as blood filled the water, and swarms of excited fish snapped up the scattering particles of food. Such power!
While wondering what this tropical shark was feeling with her many teeth sunk into ice, a movement caught my eye, and I turned to find Bratworst zooming in behind me. She was looking back at me from centimetres away, yet with the next beat of her tail, she failed to change direction! Instinctively, I leaned back, brought up my knees between us, and finned water into her nose. She startled, turned, and shot away.
Again Madonna snatched up the frozen chunk, and whipped it back and forth as Bratworst flew after her. When it fell, she grabbed it and and arced away with it as several more sharks joined them. The frozen food was passed from shark to shark a number of times, then fell in the coral, and in a moment of calm, I replaced it on the sand. Never had I seen anything so tortuously mangled in my life.
More sharks were arriving, all of them thrilled with the situation and I drifted away from the food, watching in growing confusion and trying to keep track of everyone. My goal in those early sessions was to identify each shark present--I could only recognize about nine for sure at the time.
Soon I again sensed motion behind me and turning, found Bratworst shooting up my body. Already she was passing my face and another larger, agitated shark was beside her, also centimetres away from me. But the two changed their trajectory the moment I faced them.
Stunned by the circus I had precipitated, I retreated from the food and looked around at the endlessly appearing, disappearing, circling sharks that were still accumulating. Sharks were passing in the coral everywhere I looked to the limits of visibility. I tried to note dorsal fins and distinctive markings, turning continuously to keep track of the confusing scene and make sure that no one was coming in from behind me.
I was still worried that Madonna might be suffering from a bad reaction to ice, and kept a concerned eye on her as she circled through the area, intermittently passing nearby. Her mouth was cut and I assumed she had hurt it during her efforts to bite into the frozen fish scraps. It wasn't until weeks later when my film was developed, that my photograph showed that her mouth was already injured when she arrived that morning.
Bratworst roamed around with the rest, often passing close by me, too, and finally, mesmerized by the continuously moving scene, I gave up and just stared around and around and around. . . and that was when it came to me: all the sharks were females!
This unusual session raised many questions, including a mystery that took years to understand.
The realization of the segregation of the females within the lagoon was an important breakthrough and I learned in conversation with spear fishermen that they often trail their catch of fish on a string behind them, which motivates the local sharks to come darting in and try to take them. That explained the behaviour of the two sharks who had approached me from behind. But they learned that in this situation the food was to be found on the sand and none never approached me from behind again!
Then there was the question of the numbers of sharks that had gathered so suddenly—many times the usual number—and all of them excited. At each former session, the same few sharks had come within the first half hour. They had not seemed to consider eating very urgent, and had not been excited. Though it seemed possible that Madonna had become agitated over her difficulties with the frozen chunk, and that her mood had communicated instantly to Bratworst, and then to all the new arrivals, I was not sure about that. Something had been different. It became one of my unsolved mysteries that events like this unfolded sometimes for no apparent reason. The 154th session was one such time--sixty-five excited sharks had come, twice the usual number.
On another occasion, it was nearly dark when I moved a scrap out from beneath a coral ledge. Though it had been ignored throughout the session, a visiting blackfin soared in, grabbed it, shook it, and when she dropped it, several tons of nurse sharks converged upon the morsel. Then forty blackfins shot in and circled at top speed as the nurse sharks rose vertically, their tails thrashing the surface, in their urgent efforts to scrape off a crumb.
The shadowy green waters were shot through with sharks orbiting the centre like stars around a black hole. There were so many present that there was not enough space—multitudes were zooming past as if I were not there, sharks known and unknown. The air of seriousness among them began to feel menacing, quite apart from the danger of collisions. Gazing, riveted, I felt I was looking upon a scene of utter madness, that I was an alien, fragile observer, hopelessly apart from it. Never, anywhere, even on television or in films, had I seen such a spectacle.
Finally I figured it out. The sharks were socializing. They travelled in concert with the lunar phase, and when the moon was full they often had visitors. They also seemed to become especially excited at that time. The shark tornadoes that developed at times as the full moon rose were breathtaking. An old lady shark who normally never accelerated would suddenly shoot vertically, shake off her remora, and streak away out of sight so fast that the eye could scarcely follow her. Then she would rocket through the scene again, many others flying with her.
Some of my sessions were held in areas of deeper water, where the socializing sharks were easier to watch, and they could fly as they wished without the need to avoid coral obstacles. They streamed together in long ragged lines through the vast space in a revel of socializing. In the clear water, the surroundings were a beautiful deep violet twilight, and I would stay watching them until they became just movements in the dark. As I drifted away in my kayak across the glowing surface, I could still see them cavorting, silhouetted against the white sand.
So next time you see the full moon rising, remember them in their far flung societies, thrilling as the sun sets and gathering, to soar through the moonbeams in supernatural delight. Its important, because, just while I was writing this, 22,834 sharks were finned.
(c) Ila France Porcher 2017
author of The True Nature of Sharks