Galápagos Islands, above & below water - June 2006

36 photos

The Galápagos Islands are part of Ecuador and lie 600 miles off the west coast of South America. They are part of a volcanic underwater mountain range that includes Cocos Island to the north and Easter Island to the south. The main island cluster straddles the equator and includes the islands of Baltra, San Cristóbal, North Seymour, Bartolomé, Española, Fernandina, Floreana, Genovesa, Isbela, and South Plaza.

Because of the distance, access to Galápagos is generally by plane from Ecuador. Despite the location of the main island on the equator, the area is constantly swept by the Humboldt Current
that flows from the southwestern coast of Chile, northward along the western coast of South America, and reaches as far north as Peru. For those contemplating a dip in this “equatorial” water, consider that, although the air temperature is temperate to quite hot, the water temperature can be under 60 degrees. For divers, a 7mm wetsuit, with neoprene hood, gloves, and booties may or may not be enough.

These islands are home to an extraordinary number and variety of land and water animals – at last count, about 9,000! And the isolation of these islands has resulted in an extremely high percentage of animals, as well as plants, that are endemic – that exist nowhere else on earth. In fact, over 75% of the reptiles and land birds are endemic to Galapagos, as are 33% of the plants. The percentages of marine species that are endemic is smaller, but researchers have documented almost 10% of the 400 fish species to be endemic.

The most popular above-water animals include: (i) Birds – Flightless Cormorants, Frigate Birds, Boobies Blue Footed, Red Footed and Nazca), Pelicans, Flamingos, Waved Albatross, and Penguins; (ii) Land and Marine Iguanas; (iii) Lava Lizards; (iv) Giant Tortoises and Galápagos Green Turtles; and (v) Galápagos Sea Lions and Galápagos Fur Seals. (Note that Fur Seals are, technically, sea lions and not actual seals.)

The islands were made famous by Charles Darwin, an English naturalist whose study of animal life in the islands also made him renown. He conducted his research during the course of a voyage to the islands in 1835, on board HMS Beagle. His research established the theory of evolution, by which all species of life on earth descended from common ancestors, through a process he called natural selection. His research on evolution was published in 1859, in his book On the Origin of Species, and within ten years, his theory was accepted as fact by the scientific community and much of the general public. However, his theories met resistance from the church, so that the present broad consensus on Darwin’s modern evolutionary synthesis – in which natural selection was the basic mechanism of evolution – did not solidify until the 1930s to 1950s.

Of interest to divers are two other islands, Wolf and Darwin Islands, which lie relatively close to one another and about 200 miles north of the main equatorial islands. The bad news for tourists is that people are not allowed to go ashore on either of these islands. The good news for divers is that the water is much warmer, often in the high 70s, and the underwater marine life is extraordinary. In addition to Galápagos Sea Lions and Galápagos Fur Seals, there are other attractions for divers, including the schools of literally hundreds of Scalloped Hammerhead Sharks that live around these islands, particularly Wolf Island. Although the number of these sharks varies with the season, and with outright luck, a diver will often see literally hundreds of these animals at any given time. Despite their fearsome, prehistoric appearance – and their size up to 12 feet or so – these Hammerhead Sharks are not aggressive toward humans. Indeed, their shyness presents a logistic problem for underwater photographers seeking close-range images. The diver must hide behind rocks, 80 feet or so down in the water, in order not to scare off the Sharks; and then, as the sharks approach, the photographer can rise slowly and take a series of shots, using motor-drive.

Although sharks are fish, they – along with rays – are cartilaginous fish and do not have bones, as do most other fish. These animals evolved 350 million years ago, 100 million years before the first dinosaurs, and have not substantially changed in the last 150 million years. The muscle structure and body movement of sharks are fascinating.
In simple terms, their flexible cartilage skeletons are wrapped with two sets of opposing, helical muscle bands, and their skin is attached directly to the underlying muscle tissue. This makes the swimming motion of sharks much different than that of bony fish. Rather than finning their tails back and forth as bony fish generally do, sharks swim by moving their entire bodies in a beautiful, sinuous manner. When one becomes accustomed to diving in the midst of sharks, he will begin to see, and appreciate the real beauty of this full-body undulation.

Hammerhead Sharks are unique, in the structure of their heads and the placement of their eyes at the outside ends of their “hammer” heads. This gives Hammerheads superb binocular vision, and they apparently also have excellent vision up and down as well.

In addition to Scalloped Hammerhead Sharks, the waters around Wolf and Darwin Islands also seasonally support Whale Sharks. These animals are the largest fish on earth, growing up to 45 feet in length and 13 tons in weight – the size of a bus. Whale Sharks are filter-feeders, more like whales than other species of sharks; and, while they are huge, they do not pose any serious threat to humans.