Darwin Bay on the north-easterly island of Genovesa is a wonderful place to snorkel. It is also the site of the first dive in Galápagos waters back in 1925. On 9 April, gung-ho American naturalist and explorer William Beebe sent for his diving helmet. It was a classic bit of kit, a cumbersome copper affair replete with reinforced glass and rivets that left Beebe looking like a cross between a medieval knight and a Doctor Who cyberman. He plugged a hose (‘of the common or garden variety’) into the right ear of the helmet, through which one of his colleagues at the surface pumped a steady supply of air.
Beebe descended slowly to a depth of around 5m and took in his surroundings. At first, it all looked much as things had done during practice sessions he’d conducted at the New York Aquarium. So he sat down, Zen-like, on a convenient rock, shut his eyes and took a moment to reflect. ‘I am not at home, nor near any city or people; I am far out in the Pacific on a desert island, sitting on the bottom of the ocean; I am deep down under the water in a place where no human being has ever been before,’ he wrote in The Arcturus Adventure.
FIGURE 2.1. William Beebe. The American naturalist and explorer was the first person to dive in the Galápagos in 1925. His helmet—‘a big, conical affair of copper’—weighed almost 30 kg. Reproduced from William Beebe, The Arcturus Adventure (New York: Putnam, 1926).
When he opened his eyes again, Beebe found himself staring at a bizarre fish, ‘the strangest little blenny in the world, five inches long and mostly all head’. Its long snout, flaring nostrils and two horn-like structures that curved from the top of its head made it look absurd, almost like a prize bull. ‘My blenny’s eyes were silver with hieroglyphics of purple in them, and as I looked, he puffed a puff of water at my window and was gone.’
Beebe made five rapturous dives that day. In spite of all his preparation, he was nervous, especially during his second descent. Treading water beside the flat-bottomed research boat, just about to duck into the helmet to commence the dive, he saw a huge shark, ‘a giant of a generous eleven or twelve feet, cutting the water with his great dark fin’. The sight would have been enough to send most people scrambling back up the ladder and into the boat, but this was not an option. Beebe had been forever telling his colleagues that sharks are harmless; he could hardly bottle out now.
On the bottom, with the shark still on his mind, he found the restricted field of vision imposed by the helmet somewhat alarming. ‘I am certain that from above I must have looked like some strange sort of owl, whose head continually revolved first in one and then in the opposite direction,’ he wrote. To make matters worse, he found the fish around him incredibly curious. Triggerfish are notorious in this respect, their colourful, rhomboid bodies forgoing their usual preoccupation with crustaceans to take a nip at a passing diver or snorkeler. ‘I would often leap up in expectation of seeing some monster of the deep about to attack me,’ wrote Beebe.
Once he’d calmed down, he was able to take in his surroundings. The sun’s rays filtered down from the surface ‘as though through the most marvellous cathedral’. He saw white-striped angelfish chasing one another ‘in sheer play’; brightly coloured wrasse ‘slender and supple as eels’; a mist of yellow-tailed surgeonfish passing before him; an octopus flowing over a rock ‘like some horrid viscid fluid in animal form’. Fairly limited in his movements owing to his weighty diving clobber, Beebe soon hit upon the idea of waving a freshly killed crab through the water to bring the fish to him. Within minutes he was surrounded by hundreds of specimens from dozens of different species. ‘Their keen powers of scent drew them like filings to a magnet,’ he wrote. ‘Often there was a central nucleus a foot or more in diameter, of solid fish, so that the bait and my arm to the elbow were quite invisible.’
Impressive as this kind of experience might be, it’s worth bearing in mind that it is necessarily superficial. Far deeper down than it’s possible to dive with scuba gear, there exists an entire world that few humans have ever set eyes on. In the 1970s, marine geologists got the first glimpse of it in the waters around the Galápagos, when they dropped a probe overboard and lowered it to a depth of several thousand metres into the vicinity of the Galápagos Rift (the east-west cleft between the Cocos Plate to the north and the Nazca Plate to the south, lying some 250 km north of Puerto Ayora on Santa Cruz). They were looking for signs of so-called hydrothermal vents discharging plumes of superhot water from the sea floor. Photographs and temperature measurements taken by the probe produced the first clear evidence of these chimney-like structures that we now know are a feature of all the world’s oceans. One of the photographs revealed something even more surprising. It is grainy, but one can still make out a clump of giant mussels, each about 15 cm long. A little way off, a crab scuttles across the lava bed.
In 1977, the US National Oceanic and Atmospheric Administration sent the deep-sea submersible Alvin through the Panama Canal to take two men down for a closer look. In February and March, they made twenty-four dives in the region where the 1976 expedition had produced its photos. The warm, chemical soup spewing from these vents seemed sufficient to sustain an entire community of weird creatures in total darkness at extraordinary pressure. When Alvin focused its beams on the craggy lava floor of the Galápagos Rift, it shone light on a monstrous abundance of giant mussels, crabs, oysters, limpets and tubeworms growing up to 3m long.
Floating in the huge water column above, many more species have yet to be seen, let alone described. Beebe caught a few of these, like a lanternfish netted en route from Genovesa to Isabela. Bringing it into the dark room on board the research vessel Arcturus, he marvelled at the ‘little eruptions of body fires which flashed forth’ from its flesh. Dredging off Fernandina, Beebe’s team pulled up a couple of anglerfish with their weird lamp to illuminate the pitch before them. The BBC’s 2006 three-part documentary Galápagos provides an even more impressive glimpse into this unknown world when one of the cameramen braves a night dive far out at sea to film the bizarre luminous creatures that drift up to the surface when it’s dark. As the Galápagos National Park Service does not normally permit night diving, only through films like this can we see this other world. But it’s exciting to think it’s out there.
FIGURE 2.2. Three new species of lantern-bearing anglerfish or ‘sea devils’. This was the kind of extraordinary life that Beebe’s team brought up from the deep, dark water to the northeast of the Galápagos. Reproduced from William Beebe, The Arcturus Adventure (New York: Putnam, 1926).
Of course Charles Darwin saw none of this hidden world. His total fish haul in 1835 was just fifteen species, netted from the shallow waters around San Cristóbal and Floreana and preserved in a cask of wine. There were a few interesting species amongst them: the Galápagos sheepshead wrasse with ‘four very conspicuous, strong, curved, canine teeth’ sticking out from the front of each jaw; the tiny red clingfish, which looks like it might have been hiding away in a crevice since the Cambrian era; and the bullseye puffer, which surprised Darwin by making a ‘loud grating noise’. Although Darwin’s fish collection from the Galápagos was not much to write home about, it nevertheless hints at the amazing diversity: all the species he collected were new to science, ‘without exception’.
It is also clear from Darwin’s diary just how rammed with life the Galápagos waters used to be. ‘Fish, Shark & Turtles were popping their heads up in all parts,’ he noted at an anchorage off the west coast of San Cristóbal. The Beagle’s crew eagerly flung fishing lines overboard and quickly hauled in ‘great numbers of fish’, many of them huge at almost 1m long. ‘This sport makes all hands very merry; loud laughter & the heavy flapping of the fish are heard on every side,’ he wrote.
This productivity is, in large part, down to the cool, nutrient-rich waters that reach the surface in the Galápagos. The Beagle’s captain, Robert FitzRoy, was fascinated by the islands’ ‘very remarkable’ currents, noting their speed, persistent direction and also the ‘surprising difference in the temperature of bodies of water moving within a few miles of each other’. To the east of Isabela, for instance, FitzRoy found the surface water to be a comfortable 26°C. On the island’s western shores, by contrast, the sea temperature was over 10°C lower.
This striking difference is a result of the currents that meet in the Galápagos (see Appendix C, Figure 4). The strong, cold Humboldt Current flows up the coast of Peru, combining with the weaker, warmer Panama Current from the north to form the South Equatorial Current, which surges out into the Pacific from east to west along the equator. The Cromwell Current (or Pacific Equatorial Undercurrent) runs in the opposite direction, a deep course of even colder water coming in from the west. When this hits the western edge of the Galápagos, it has nowhere to go but up, bringing its especially chilly water to the surface around Fernandina and the west coast of Isabela.
These currents have a major influence on the peculiar climate in the Galápagos. Between June and November, the Humboldt Current is the major player, its cold, north-westerly influence turning down the temperature in the islands. During this cool season, there is precious little rain along the coast, but at higher altitudes any moisture in the warmer air tends to condense into a drizzling mist, or garúa. When the Humboldt slackens in December, the Panama Current becomes ascendant, the mist evaporates from the highlands and the hot season begins. As the temperature of the water rises, evaporation increases, clouds grow and rain falls. In an El Niño year, when the Panama Current is particularly warm, the Galápagos can experience a deluge.
Beebe may have encountered what we’d now consider to be an El Niño. ‘Rain in the afternoon and showers in the evening,’ he recorded in the Arcturus logbook on 8 April 1925, the day before he tried out his diving helmet for the first time. Although he had been to the Galápagos once before, at around the same time of year in 1923, the rain in 1925 seemed exceptional. A couple of weeks later, on Española, Beebe noted ‘small greenish rain pools deep among the rocks’ and a freshwater pond ‘a half-mile in length’.
The conditions in 1924–1925, however, were nothing like those experienced in 1982–1983, when more than 3,500 mm of rain fell on Puerto Ayora, roughly ten times more than normal. High sea levels, heavy swells and turbulent waters caused widespread erosion; ‘stupendous thunderstorms’ resulted in flash flooding and human fatality. In 1935, Norwegian settler Alf Kastdalen had been one of the first to make a go of life in the Santa Cruz highlands. As a farmer, he had a special interest in the weather, noting how a creek near the family home would flow regularly in some years and be bone dry in others. In 1983, Kastdalen—then in his sixties—was electrocuted as he tried to replace a high-tension cable torn down by the El Niño elements.
Inshore
In addition to affecting the climate, the currents obviously also have a major influence on what goes on beneath the water. When the Humboldt and Cromwell Currents are dominant, they bring nutrients lapping up against the Galápagos shoreline, feeding blooms of plankton and allowing sun-loving algae and grasses to bed down on the pillows of lava beneath the surface. These two currents are also rich in oxygen, which makes life a lot easier for filter feeders like sponges and corals, invertebrates such as sea stars and urchins, and almost five hundred species of fish.
Some of the most productive waters are in the Bolivar Channel between Fernandina and Isabela (where Captain Morrell witnessed the violent eruption in 1825). Beebe noted the extraordinary diversity and abundance of species when, diving off the north coast of Fernandina, he found himself ‘amidst sea-weed so tall and thick it was like a corn-field’. A gang of giant sea bass (‘too ugly and dangerous to call a school’) came mooching through the waving weeds, all of them olive and brown, ‘their ugly jaws chewing eternally on the cud of life’. Then Beebe caught sight of a glimmer of gold in their midst, a fish that seemed to be part of the shoal, nudging its neighbour and getting nudged back in return.
Darwin collected this species, though as he only netted a ‘mottled brown’ specimen he could not have guessed, as Beebe did, that it comes in different colours. The bacalao (as it’s known) is the largest sea bass living in the Galápagos, with some specimens weighing more than a human toddler and around one in twenty coming in the mysterious golden form. Other fish families have similarly confusing morphs, notably the hogfishes and wrasses, several species of which can vary from the drab to the distinctly psychedelic. One of the largest in the Galápagos is that sheepshead wrasse that Darwin saw (sometimes more than 70 cm long), which varies from red to bluish-grey (though a blazing spot above its pectoral fin remains a constant gold). The guineafowl puffer too comes in a couple of different forms: either in black with white polka dots (like a guineafowl) or in a stunning golden form. As yet, nobody has come up with a satisfactory explanation for why one species should come in different colours, but more than likely it has something to do with sex.
The bacalao and other sea bass, the hogfish, the wrasse and the guineafowl puffer all turn out to be hermaphrodites. This means they’re able to produce both eggs and sperm, though probably not at the same time. Most of these species start out life as females, with only their egg-producing tissue active. Then at some stage, triggered by as yet unknown cues, the females undergo a sex change and switch to producing sperm instead. In some cases, it’s possible that this radical transformation is accompanied by spectacular changes in colour.
The fact that we don’t really know the reproductive set-up for most of these bizarre fish is of more than just academic interest. If we don’t know how they breed, we can’t anticipate how the population will fare when faced with pressures from fishing or climate change. This is of particular concern for a species like the bacalao, one of the most commercially valuable fish in the Galápagos. It is thought that in the 1980s this one species made up as much as 40 percent of the value of the total catch. It remains sought-after today, particularly the rare golden form, though over the last few decades Galápagos fishermen have turned their attentions to the even more lucrative spiny lobsters and sea cucumbers, also at their most abundant in the Bolivar Channel.
Before the Chinese began to pay big bucks for sea cucumbers, nobody thought to fish them from Galápagos waters, and there would have been thousands lying on the sea floor off an island like Fernandina. By the time of the first official census in 2001, an area the size of a football pitch held just 115 specimens of the Galápagos sea cucumber, the species that is commercially exploited. Today, the same area is home to fewer than five. For a creature that relies on sperm and egg finding each other in the water column, such ridiculously low densities spell almost certain extinction.
The abundant plant life attracts turtles too. There are occasionally hawksbills, but the Pacific green turtle is by far the most common species in the Galápagos. It dines on a diet of algae and seagrass, supplemented by the occasional mouthful of mangrove or bite of crustacean, so tends to hang out in protected bays, inlets and lagoons. The females lay eggs between December and June, returning in the cover of darkness to the beach on which they hatched to carve a pit-like nest chamber in the sand. They can drop as many as eighty golf ball–sized eggs into the nest, before covering them with sand and returning to the sea, a feat that a female may repeat several times over the course of the season. Between six and ten weeks later, the hatchlings emerge. Most of them do this at night, when there are fewer predators about, but many still succumb to the eager ghost crabs and yellow-crowned night heron that line up in wait.
Fur Seals and Sea Lions
The cooling, sustaining effects of the Humboldt and Cromwell Currents also make the Galápagos habitable for fur seals and sea lions, creatures more often associated with ice than with the equator. But it’s a perilous existence. When the life-giving currents stall, a devastating chain of events ripples through the Galápagos ecosystem. First to go is the microscopic plant and animal life, followed swiftly by the fish that feed on them, and so on, all the way to the fur seals and sea lions near the top of the food chain. During the particularly harsh El Niño of 1982–1983, for instance, almost every fur seal pup under the age of three years died.
In spite of the frequency of this devastating collapse in the productivity of Galápagos waters, the fur seal and sea lion appear to have survived here for hundreds of thousands, if not millions, of years. But by surveying a map of where these species prefer to hang out, it’s clear that the fur seals favour the west of the archipelago where they have access to the resource-rich Cromwell Current. Sea lions, by contrast, which are larger and so can dive to greater depths, are able to survive throughout the archipelago.
Owing to the frequent fluctuations in the marine environment, these marine mammals all show considerable flexibility in their behaviour, particularly when it comes to reproduction. They must be prepared to mate whenever the conditions are right. This need to breed at short notice places a particular burden on bull fur seals and sea lions, which cannot afford to let up in their defence of a territory. They put so much effort into keeping their harem of females all to themselves, they hardly have time to eat. A sudden shortage of food can be fatal. In the 1982–1983 El Niño, for example, almost all territorial bull fur seals and sea lions disappeared, presumed dead.
Even with all the effort they put in, bull sea lions in the Galápagos don’t get as much paternity as they might hope for. In the case of the elephant seal of Antarctica, where dominant males are colossal and only need to fight off other males for a few crucial days when females are fertile, they are able to do most of the mating and father most of the offspring. In the Galápagos, this is not the case. A bull sea lion simply can’t rebuff the advances that smaller males continuously make on the females in his harem, and quite a few of these others end up as fathers too.
Females don’t have it easy either. Compared with their closest relatives that inhabit the poles and can be weaned at just four months, fur seal and sea lion mothers in the Galápagos must provide milk for their offspring for up to three years. This means that if they give birth the following year (as they sometimes do), they might have a yearling and a newborn pup both expecting milk. Unless the conditions are really good, it just may not be possible to juggle two youngsters like this, and one of them will die.
Dolphins and Whales
Much as they were abundant with fish in Darwin’s day, the Galápagos waters were once also flush with dolphins and whales. These creatures—principally the sperm whale—led to the first commercial exploitation of the archipelago. In April 1794, James Colnett, captain of the British whaling vessel HMS Rattler, elaborated on the abundance of the creatures. Cruising to the west of the islands, his crew encountered sperm whales ‘in great numbers,’ he wrote of his whale-scouting expedition a few years later. The more experienced whale hands on board ‘uniformly declared that they had never seen spermaceti whales in a state of copulation.’ There were also newborns, which he judged were about the size of small porpoises. ‘I am disposed to believe that we were now at the general rendezvous of the spermaceti whales from the coasts of Mexico, Peru, and the Gulf of Panama, who come here to calve,’ he wrote. It was an astute observation. For some reason, as yet unknown, females and their young remain in Galápagos waters throughout the year, whereas the far larger males only make the occasional appearance to mate. For the whaling fleets that subsequently descended on the Galápagos, these sperm whales were big business. ‘The situation I recommend to all cruizers,’ wrote Colnett.
Today, the descendants of these and other cetaceans (the collective name for porpoises, dolphins and whales) are no longer harpooned but revered, with more than a dozen dolphin species and about as many whale species sighted in the Galápagos Marine Reserve. As the whaling fleets that followed in Colnett’s wake discovered, the best place for a cetacean encounter is to the west of the islands. It’s here that tourists are most likely to find bottlenose dolphins riding the bow waves of their vessels, to glimpse a pod of orcas or even to see the flukes of a blue whale in the distance. But the actions of Colnett and his fellow whalers mean that such sightings are relatively rare, even today.
Rays and Sharks
By contrast, rays and sharks are far easier to spot. Snorkelers and divers will frequently encounter stingrays, spotted eagle rays, golden rays and sometimes even the vast undulating manta ray. The whitetip reef shark, a wide-ranging species with a telltale daub of creamy white on the tip of its dorsal and caudal fins, is still fairly common in both the Pacific and Indian Oceans. The Galápagos shark, in spite of its name, is not unique to the archipelago; it was just discovered here. ‘We examined a large number of them, several hundred being taken aboard the schooner, and we saw probably thousands in the water,’ wrote the scientists of the California Academy of Sciences in 1905.
They found the Galápagos sharks most abundant around the north-westerly outlying islands of Darwin and Wolf. This is the best place to see scalloped hammerhead sharks, particularly just to the south-east of Darwin, where they congregate in great numbers during the daytime. It remains a bit of a mystery why they do this. It could be that the currents are favourable, allowing the sharks to rest up before they head out at dusk to forage. Perhaps this schooling fulfils some as yet unknown social need. They could be coming together to attract the services of smaller fish that will pick parasites from their skin. Darwin Island could just be conveniently close to the shoals of smaller fish on which they feed. Whatever the reason, congregations of scalloped hammerheads and smooth hammerheads, as well as the chance of seeing a colossal whale shark, draw a lot of visitors to this corner of the archipelago. The six dive sites dotted around the islands of Darwin and Wolf are the most highly sought of seventy-five dedicated marine visitor sites in the Galápagos and crucial to the buoyancy of the island’s dive tourism industry, estimated to be worth some $20 million a year.
Remarkably, William Beebe seems to have anticipated the interest that people would have in diving. ‘I am deep down under the water in a place where no human being has ever been before; it is one of the greatest moments of my whole life,’ he wrote. And then, in a throwaway adjunct, he reckoned that ‘thousands of people would pay large sums, would forego much for five minutes of this!’
How right he was.
