THE GALAPAGOS: Darwin Island's Fiercest Apex Predators

The undersea world of the Galapagos Islands. Among the richest, most exotic, and least explored waters on Earth. These islands reveal our planet's foremost laboratory of evolution. The process occurs right before your very eyes. Plants, birds, and animals adapting and changing at an astonishing rate. But few people realize that the same process occurs underwater. We'll journey to these extraordinary islands and document some of the bizarre and fantastic life forms found both above and below the water. We'll also join an expedition to remote Darwin Island. Here, we'll experience remarkable encounters with massive schools of hammerhead sharks and a giant among fish, the whale shark. And finally, we'll examine an issue that threatens to destroy one of the world's last remaining pristine ecosystems. The Galapagos are remote specks of land in a vast Pacific Ocean. The islands lie uniquely isolated on the equator, 600 miles west of Ecuador in South America. Over 5 million years ago, successive volcanic eruptions formed an underwater platform with towering mountains. The highest peaks rose above the surface, creating an island chain known today as the Galapagos. From the 1600s, they were a lonely refuge for pirate and whaling ships and vessels that strayed off course. In 1835, the islands were visited by a modest, unknown scientist named Charles Darwin. He would be the first scientist to set foot on her shores. He signed on as ship's naturalist for a five-year expedition aboard the sailing vessel Beagle. Traveling north on the prevailing currents, which ran parallel to the South American coast, the ship stumbled upon these islands by accident. Darwin and the Beagle's crew beheld a bizarre and fantastic world unlike anywhere else on Earth. It was a remarkable spectacle. They saw strange birds of all shapes and sizes, massive tortoises weighing hundreds of pounds, and mammals more commonly seen in colder climates. But the Galapagos straddled the equator. Darwin saw iguanas that fed in the sea, creatures adapted to eat algae and plants under the water. Wandering its shores, he found a naturalist's paradise so strange and wonderful that it would forever change the course of Western thought. Darwin visited only four of the 16 major islands, spending a mere three weeks. He filled his bags with specimens, took notes, and left. However brief the visit, it was one of the great events in the history of science. Darwin's observations shook both the scientific and religious foundations of the world. What Darwin couldn't have imagined was that the undersea world of these islands was as astounding as that above water. Today, divers and scientists have the means to explore a world Darwin never dreamed of. Evolution is a property of all life, whether it occurs on land or in the water. The same processes are at work, the same consequences of evolution are seen in the ecosystems from the ocean depths to the tops of mountains. Fish also have the advantage of the mobility of the ocean currents and the fact that the ocean is something that they can traverse in every direction. We see that on land only in the way that birds can migrate thousands of miles, thousands of kilometers twice a year. Fish have the ocean currents they can ride, ocean currents they can be dispersed on, colonizing new areas. This in turn feeds the evolutionary mosaic that's continually being played out in these systems. To seed new areas with species, you can do it with eggs and larvae being transported on the currents. The transport is passive for these species. They have to rely on the vagaries of exactly how the currents go and their speeds, which makes it a very fortuitous and chance event. And it's the chance that makes the evolution so interesting. Once they've been introduced, the species may settle and evolve there themselves. That means that there's a lot of endemic species, species which are found nowhere else. And the Galapagos, at least a third of the species, are found nowhere else in the world. This is an extraordinarily high number. Ancestors of these fish were once found in the Caribbean, Atlantic and the Pacific. The vast oceans were at one time connected, allowing species to travel freely on ocean currents. Seven different currents converge on the Galapagos, from cold Antarctic to warm equatorial flows. All of these currents contribute diversity, creating a rich mosaic of marine life. Like their counterparts on land, these drifters and chance colonizers became the pioneers of the Galapagos. Marooned on these desert islands and remote seas, they managed to survive and adapt. This is where Darwin's story of evolution begins. They started to change, becoming different from their ancestors in the Americas, even different from their relatives on neighboring islands. Charles Darwin didn't know about evolution, either above or below the water. In fact, when nature revealed clues to her greatest secret, he didn't understand them, at least not right away. After leaving the islands, it took him over a quarter of a century to formulate his radical theories on evolution by natural selection. In 1959, 100 years after the publication of Darwin's The Origin of the Species, the government of Ecuador declared all areas of the Galapagos to be national parks. Marine waters joined the park system in 1986, and today over 97% of the archipelago is protected from harmful development. In 1979, UNESCO declared the islands a World Heritage Site. The Galapagos is one of the few pristine places left in the world. Unlike islands such as Hawaii, the Galapagos has only recently seen the arrival of man. The destructive presence of humans is now beginning to take its toll. Although protected, the islands are in peril. It is uncertain whether the Galapagos can survive the most traumatic of evolutionary events, the arrival of man. We began our journey in the port city of Guayaquil. After a 600-mile flight over the Pacific, we landed on the Galapagos island of San Cristobal. Here, we joined the live-aboard diving vessel, the Galapagos Aggressor. Equipped for extended stays at sea, we traveled the length of the islands in seven days. Before boarding the dive vessel, we encountered our first sampling of Galapagos marine life. Sea lions relaxed along the shoreline, sometimes taking residence in small fishing boats. The Galapagos sea lion and the fur sea lion inhabit sandy beaches and rocky shorelines. Most of their time is spent lazily basking in the sun. Sea lions are excellent swimmers and divers. As soon as they enter the water, their heart rate drops, their blood vessels constrict, and their lungs begin to collapse. Blood flows as usual to the heart and brain, but less reaches non-vital organs like the kidneys. To stay underwater, sea lions are able to draw on oxygen in the muscles as well as in their blood. Fur sea lions can be distinguished from the Galapagos sea lion by their smaller size, larger eyes, and heavier fur coats. Male sea lions are much larger than females and have a bulbous forehead. Sea lions often delight in human company, cavorting and taunting intruding divers. Perhaps the strangest of all Galapagos sea creatures is the marine iguana. These unique reptiles evolved from land iguanas, eventually turning to the sea for their main source of food, aquatic plants, and algae. They do not hold their breath and actually fill their lungs with water. Because they have no special buoyancy abilities, air in their lungs would prevent them from submerging. Once back on shore, they spit out the water and breathe normally. Another remarkable undersea reptile is the sea turtle. It's hard to imagine that the green sea turtle is an endangered species when you visit the Galapagos. Hundreds swim about the islands, oblivious to the presence of human visitors. Like their cousins, the giant tortoise, these turtles have no natural fear. This has led to their demise in many parts of the world. Ponderous on land, sea turtles swim with grace and speed in all of the world's oceans except the Antarctic. A little-known fact about the Galapagos Islands is that they have their own species of penguin. It's the only penguin that inhabits equatorial waters. During the day, using their wings as flippers, they swim out to sea to feed on small schooling fish. Visiting these islands underwater, one wonders what Darwin's reaction would have been had he been able to venture below the surface. The sheer abundance of life is staggering. Immense schools of barracuda, jacks, and dozens of other species swim in the strong currents. These currents bear nutrients and minute animals that form the basis of a complex food chain. The seven major currents that bathe the islands are responsible for an unusual assemblage of over 300 species of fish. Darwin would have marveled at these amazing creatures. Moray eels, ranging in size from only a few inches to over seven feet in length. Strange guinea fowl pufferfish that change from bright yellow to almost black with white spots. And large stingrays and eagle rays, measuring eight feet across. In order to document the marine life of the region, cameramen have to wear thick wetsuits. Even though the Galapagos straddles the equator, water temperatures range anywhere from 60 to 80 degrees. Temperatures vary depending on which current prevails. We traveled through the main group of islands for a few days and then headed north before a dazzling sunset. Most of the islands are a few latitudinal degrees below the equator. In order to reach our final destination, we had to cross the equator, as confirmed by the boat's global positioning device. After an overnight journey of over 12 hours, we reached remote Wolf Island. Wolf and Darwin are both uninhabited, impenetrable, rocky islands, home to thousands of nesting seabirds. Bottlenose dolphins greeted us with the coming dawn. A few hours later, we arrived at our ultimate destination, Darwin Island. Here we hoped for encounters with two types of sharks, scalloped hammerheads and whale sharks. We would not be disappointed. Only moments after descending on our first exploratory dive, our cameraman captured a sea turtle and some steel pompano jacks. In the distance loomed a gigantic shadow, an adult whale shark. Over the course of ten dives, we encountered whale sharks on each visit. At least half a dozen of the immense sharks cruised back and forth in the brisk currents surrounding Darwin Island. A titan among the ocean's fish, the whale shark can reach lengths of over 50 feet. This harmless surface dweller roams the world's warmer seas, feeding on tiny marine animals that are filtered from the water. These animals tolerated the close approach of divers, even allowing them to ride on their backs. Occasionally annoyed, they would dive deep into the murky water, quickly losing their passengers. In addition to their remarkable size, these animals provided an unexpected surprise, their skin. Most sharks have very abrasive, sandpapery scales that are rough to the touch. Whale shark skin, by comparison, was relatively smooth. This was a once-in-a-lifetime encounter. In addition to encounters with whale sharks, Darwin Island was also home to huge schools of scalloped hammerhead sharks. Numbering in the hundreds, these impressive predators were an imposing sight. No one knows for sure why they school in such large numbers, but the behavior is believed to be related to mating, or possibly migration. Another mystery is their oddly-shaped head. Some believe they house an enhanced sensory system used to detect prey. Others believe the shovel-shaped hammers are used to aid in apprehending fish, like the bottom-dwelling stingray. Once thought to be man-eaters, hammerheads have proven to be either indifferent to, or even wary of, man. The tameness of Galapagos animals in marine life is due to the lack of large predators. It doesn't occur to them that we may be here to kill them. But nature lacks foresight and failed to anticipate the coming of man. Early sailors took cruel delight in slaughtering helpless animals. But today, killing a seal or tortoise above the water is unheard of. Yet foreign fishing vessels routinely fish illegally around the islands. One of the world's sacred places is under attack from two of the usual suspects, greed and ignorance. Cruising past Wolf Island, we were astonished to see several fishing boats only a few hundred yards from shore. Large high-tech fishing vessels, like this ship, flaunt the laws of Ecuador and haul out hundreds of tons of tuna, sharks and other food fish. An ever-growing Asian demand for shark fins and meat is now threatening these apex predators. With no resources to pursue and punish the offenders, officials are powerless in the face of this increasing threat. Our captain radioed the Ecuadorian Coast Guard to inform them of the infraction. A park guide videotaped the offending ship for proof of their activities. We found out later that the ship simply left Ecuadorian waters, probably with a full hold of illegally caught fish. Apex predators feed at the very top of the food chain. When you remove them from the food chain or decrease their abundance greatly, it can have a number of consequences. It's difficult to predict them because apex predators, by their very nature, feed on many different kinds of species. That makes it very difficult or impossible for scientists to predict in advance what the consequences are. When you remove an apex predator, some of the things that it feeds on are likely to increase in abundance. You could also be very unlucky, and the things which increase in abundance are themselves voracious predators and have detrimental impacts. Because of their remoteness, the Galapagos Islands, especially Wolf and Darwin, are easy piggings for fishermen. Under intense international pressure, the government has tried to limit these activities, but failed consistently. Some politicians have even pressed for and received concessions to allow fishing. After bans were implemented on shark and sea cucumber harvesting, fishermen staged violent protests, taking hostages at the Darwin Research Station. They also threatened to kill precious captive tortoise populations. Authorities eventually caved in, allowing limited fishing. It is virtually impossible to please everyone in this very complex issue. Without a viable alternative, impoverished fishermen have little recourse but to break existing laws. But there is no excuse for the actions of foreign vessels in these waters. Many people are aware that the bird and land animals in the Galapagos have some of the highest protection in the world. You can't step off a trail when you're being taken around to view the products of evolution at work. The government has tried to create the same protection for the marine environment, but it needs the same kind of enforcement, the same kinds of surveillance, for the benefits of that protection to actually be experienced. Protection and enforcement on land is possible. You can regulate where people go and when they go there with the presence of guides and enforcement officials. You need the same kind of presence, the same kind of enforcement to protect the underwater environment. And that's very difficult to achieve, costly, takes a real commitment. But without it, it's very difficult to be optimistic. Tourism is the least of the Galapagos problems and may actually be their ultimate savior. Visitors come here to see wildlife in a pristine state. If the ecosystem is damaged by fishing, no one will want to visit the islands, thereby destroying the main source of income for most residents. There are other pressing problems in these troubled waters. The permanent human population of the islands is increasing at an exponential rate, placing a strain on very limited resources. The Galapagos Islands are at a crossroad. We witnessed undersea marvels that will quickly disappear if the situation remains unchanged. The world must recognize this precious resource and the implications of its demise should nothing be done.