In 1989 CEDAM International, an organisation dedicated to the preservation and conservation of the marine environment, brought together a panel of experts to draw a list of marine areas worthy of special protection. This list was announced as the Seven Wonders of the Underwater World. It will hardly come as a surprise that Galápagos Islands feature on this list. I believe that the exceptional underwater life around two most northern islands of the archipelago, Darwin Island and Wolf Island, is the reason for this recognition.
Darwin Island lies 160 km northwest from Isabela, one of the main islands of the Galápagos archipelago. The island does not provide a natural berthing place so it is no wonder that the first land visit happened only in 1964 with a help of a helicopter. The massive tip of a now extinct and mostly submerged volcano, that rises a thousand meters from the sea floor, now offers nesting and breeding opportunities to many sea birds.
Winds and waves formed an impressive stone arch on a rocky outcrop located less than a kilometre away from the main island. The formation is known as Darwin's Arch and, in my mind, belongs to the top ten dive sites worldwide. The walls of the jagged rock underneath the arch are washed by raging sea currents frequented by whale sharks, whales as well as large schools of Hammerhead sharks.
Research performed in 2009 and 2010 by the Charles Darwin Foundation, University of California – Davis and the Galápagos National Park described the daily behaviour of the hammerheads. The sharks tend to stay close to the rocky areas, generally lazing around during the day. Occasionally they swim away from the island toward the open water and back. The longest recorded swim was 40 km out to open ocean and then back to the island. How they navigate is not clear. Klimley (1993) suggests that they use geomagnetism of the sea floor. In open water they dive deep (one tagged shark descended to 936 m) to recalibrate their inner compass. Primarily during night and in the open ocean they sometimes move erratically. It is fair to assume that this happens when they hunt squid, which present almost 90% of their diet (Castañeda-Suárez and Sandoval-Londoño, 2007).
It was getting late. When the sun sinks low above horizon and the wind makes the surface choppy, the light does not have much chance to penetrate deep. Four of us out of usual seven were up for this dive. We encountered a big school of jacks shortly after a negative entry in front of the Darwin's Arch. My three buddies went to check the jacks out. I felt the low light would not suit a good picture. I stuck with our dive guide Juan Carlos and gave the others a few moments with the Jacks. As it took some time Juan Carlos and I moved closer to the reef to find a good spot for watching the hammerheads.
The hammerheads are shy creatures. Afraid of bubbles. It is almost certain that a hammerhead gliding lazily in a current will change direction if a diver exhales good five metres away from the shark. One way how to get close shots is to keep calm and hold your breath. The other way is to feed the sharks but it is strictly forbidden at Galápagos. The advice to hold your breath seems to be countering the basic rule of scuba diving. Yet diving with hammerheads at Darwin consists of sitting at constant depth and watching them swimming around. Thanks to this technique I usually resurfaced with my tank half full after an hour in 20 metres.
...And they arrived. One, two, five, eight, forty...
There were moments I did not know where to turn my camera as they were everywhere. Over my head. From the left. The right. Behind me. I just screamed through the regulator when I thought I got a shot. I was on the verge of breathing through my ears but in the end it did not matter, the hammerheads did not have space to avoid my bubbles anyway. This took a good fifty minutes. Suddenly a nudge to my shoulder scared me to death! Hammerhead? No, Juan
Carlos reminded me it is time to go back up.
My buddies were on the boat already. It turned out that they were swept away by a current whilst they took pictures of the jacks. They had to resurface after nine minutes as the current carried them into the dangerous rocky area, which we called the “Deadly Sector #1”. Thanks to all of them for spending almost an hour on the boat waiting for the two of us.
Juan Carlos and I were ecstatic. The three were disappointed and raring for return. At least this is how Theresa described the feeling later. If I was them I would perhaps choose harsher words to express the mood of the moment. Juan Carlos called this the dive of the year so far. I do not have such an experience to compare but it certainly was mental!