<p>The greatest whale is inching away from extinction.</p>

The greatest whale is inching away from extinction.

Still Blue

Off the shores of Costa Rica, scientists study a stronghold of whales that once hovered near extinction.

This story appears in the March 2009 issue of National Geographic magazine.

In Acapulco Harbor, amid the white yachts, R.V. Pacific Storm stood out: a working boat, black hulled, a West Coast trawler in a previous life, reborn now as a research vessel. There were bigger, more opulent boats in the harbor—fortunes are invested in the white yachts of Acapulco—but this 85-foot trawler, with its grim mien and high black bow, was the ship for me. Asked to choose, from all this fleet, the vessel to carry me on a month-long cruise in pursuit of blue whales, I would not have hesitated. As Flip Nicklin and I passed our gear up the trawler's ladder and stowed it in our cabin, I felt an almost savage contentment.

Call me Ishmael, if you like, but whenever I find myself growing grim about the mouth; whenever it is a damp, drizzly November in my soul; whenever I have spent too many consecutive months at the computer keyboard, in artificial light, like some sort of troglodyte, self-imprisoned, pecking out my living, I account it high time to get to sea as soon as I can. I jumped at the assignment on Pacific Storm. As the voyage was to depart on the third of January, I made three New Year's resolutions: I would try to be an affable shipmate. I would strip all the blubber from my prose. I would refrain from making a single allusion to Herman Melville.

Did I mention we were after a white whale?

It's true. In the eastern North Pacific population of blue whales—the group that summers mostly off California and whose migration we were following south—there is a white blue whale, maybe an albino. An inflatable skiff from Pacific Storm had satellite tagged this whale off Santa Barbara four months before, but his tag, number 4172, had ceased transmitting a few weeks after implantation, and now his whereabouts were a mystery. The sun-synchronous, polar-orbiting TIROS N satellites could no longer track him, but he was one of the animals we hoped to see off Central America.

When we had settled in on Pacific Storm, Nicklin, cross-legged on his bunk, set up his Nikon D200, with its Sea & Sea underwater dome. He squeezed a dab of silicone grease from a small tube onto his fingertip and ran it around the rim of the dome's blue O-ring. He opened the back of the camera and gave a similar treatment to the O-ring at the stern. Nicklin is a new kind of whaler. His job is not to render the oil, but to capture the essence of cetaceans, and the Nikon is his favorite harpoon.

Pacific Storm put to sea. We sailed a leg due south to avoid the Tehuantepec winds along the eastward bend of Central America, then turned southwest toward the temperature anomaly that was our destination.

The Costa Rica Dome is an upwelling of cold, nutrient-rich water generated by a meeting of winds and currents west of Central America. The location is not fixed; it meanders a bit, but the dome is reliably encountered somewhere between 300 and 500 miles offshore. The upwell­ing brings the thermocline—the boundary layer between deep, cold water and the warm water of the surface—up as high as 30 feet from the top. Upwelling with the cold, oxygen-poor water from the depths come nitrate, phos­phate, silicate, and other nutrients. This manna, or anti-manna—a gift not from heaven but from the deep—makes for an oasis in the sea. The upwelling nutrients of the dome fer­tilize the tiny plants of the phytoplankton, which feed the tiny animals of the zooplankton, which bring bigger animals, some of which are very big indeed.

The blue whale, Balaenoptera musculus, is the largest creature ever to live. Linnaeus derived the genus name from the Latin balaena, "whale," and the Greek pteron, "fin" or "wing." His species name, musculus, is the diminutive of the Latin mus, "mouse"—apparently a Linnaean joke. The "little mouse whale" can grow to 200 tons and 100 feet long. A single little mouse whale weighs as much as the entire National Football League. Just as an elephant might pick up a little mouse in its trunk, so the elephant, in its turn, might be taken up by a blue whale and carried along on the colossal tongue. Had Jonah been injected intravenously, instead of swallowed, he could have swum the arterial vessels of this whale, boosted along every ten seconds or so by the slow, godlike pulse.

The great swimming speed of the blue whale, together with the remoteness of its stronghold—where three of Earth's oceans merge in the ice-cold waters around Antarctica—protected most of the species until early in the 20th century. With the invention of explosive harpoons and fast, steam-powered catcher boats, the stronghold was breached. Through the first six decades of the 20th century 360,000 blue whales were killed. The population around South Georgia Island was extirpated, along with those that once fed in the coastal waters of Japan. Some blue whale populations were reduced by ninety-nine one-hundredths, and the species tipped at the very brink of extinction.

For Bruce Mate and John Calambokidis, the head scientists aboard Pacific Storm, the irony is deep and poignant. The blue whales they study, the 2,000 animals that summer off western North America, once just a splinter group, now make up a significant population.

Mate, director of the Marine Mammal Institute at Oregon State University, is the world's most inventive and prolific satellite-tagger of whales. The dome first caught his attention in 1995, when a blue whale he had tagged off California in summer began transmitting from off Costa Rica in winter. Calambokidis, a co-founder of Cascadia Research, in Olympia, Washington, is the West Coast's most prolific photo-identifier of whales. A tall, lean biologist with a Quaker seaman's beard and monomaniacal dedication to bringing back diagnostic images, Calambo­kidis was tantalized by the reports from the satellite. In 1999 he made a reconnaissance of the dome by sailboat. The voyage was plagued by bad weather, and the sailboat was too small for its mission, yet at the dome Calambo­kidis managed to photo identify ten whales that he had photographed off California.

Why would a blue whale depart its feeding grounds at the end of summer and migrate thou­sands of miles to spend winter in this tropical zone of upwelling? Mate and Calambokidis thought they knew. The satellite data showed that some of the tagged whales lingered five months or more at the dome, arriving early in the southern migration and departing late—a pattern that, in other species of baleen whales, is seen in pregnant females and new mothers. It had never been noted in blue whales, for the best of reasons: No one has ever witnessed the birth of a blue whale.

Gray, humpback, and right whales—the baleen species that have been studied at their calving grounds—seem to feed little, if at all, at those grounds. But there is evidence that the blue whale might be different. Given its great size and enormous energy requirements, the blue whale may be forced to find winter grounds where it can do more than snack. The oasis of the Costa Rica Dome would satisfy this requirement. Plus, the productivity of the upwelling would help nursing mothers convert schools of krill into the barrels of milk required by the calves to put on their 200 pounds a day.

Balaenoptera musculus received international protection in the mid-1960s yet, for reasons not fully understood, has scarcely rebounded. If the greatest of creatures is to come back, Mate and Calambokidis believe, its demograph­ics and its movements need to be charted. The largest remaining population of the species is most vulnerable in tropical waters where it gives birth to dainty, twenty-five-foot-long, three-ton calves.

As we followed the corridor of the blue whale migration southward, we took turns standing whale watch on the bridge, searching the horizon for blows. Whales 5801 and 23043 had already arrived at the dome, according to the satellite, and number 5670 was nearing it. The scientists were particularly interested in 23043, because they knew the sex, female, and because she had arrived at the dome early, as one might expect of a mother-to-be. The white blue whale, 4172, if he was migrating to the dome this year, was out there somewhere in the host moving south. The Pacific is a big ocean, however, and we saw not a single spout.

Now and again, day and night, the ship shifted to neutral, and the researchers put gear overboard: a CTD sensor, an echo sounder, and a hydrophone. The CTD sensor recorded conductivity (a measure of salinity), temperature, and depth. The echo sounder searched for concentrations of krill, upon which the blue whale subsists almost entirely. "We're doing some control observation on the way down," Mate explained. "If there's no krill, will the whales pass through? If there are big concentrations of krill, will they hang around? We're looking for poop. We'll try to scoop it up, see if they're feeding. And checking their breath, which is fouler when they've eaten. I don't find blue whale breath offensive—certainly not in comparison to gray whale breath, which is really foul—but blue whale breath can be strong."

The hydrophone was to detect blue whale voices. The simple song of the blue whale bull—the thumping, stentorian, basso profundo pulse of the A call, followed by the continuous tone of the B call—is the mightiest song in the sea, theoretically capable of propagating halfway across an ocean basin. But big baleen whales often run silent. Except for a few dubious snatches of song, we heard nothing at all.

When we reached the Costa Rica Dome, three days out of Acapulco, the ocean looked no different, just blue horizon and marching swells. It took a sounding by the CTD sensor to detect the thermocline lying just 60 feet under the surface. We had arrived. "Blow at eleven o'clock!" Calambokidis called down the next morning from the crosstrees, our crow's nest, over his walkie-talkie. We saw two more blows side-by-side in quick succession—our first blue whales—and we launched the tagging boats, beginning the repetitive ritual that would occupy us for the next three weeks.

The boats were Coast Guard surplus, a pair of diesel-powered RHIBs, or rigid hull inflatable boats. Sticking with meteorological nomen­clature, we called the big one Hurricane and the small oneSquall. I generally went out on Hurricane. Its commander was Bruce Mate. The second mate, and also the second Mate, was Mary Lou, the expedition videographer and the professor's wife of 40 years. I was the biopsy guy. My first job was to cock my crossbow, take a biopsy bolt from the cooler that served as ammu­nition box, nock the bolt, and then remove the sheath of aluminum foil protecting the tip from contamination by extraneous DNA. The bolt, when shot into the whale, would excise a plug of skin and blubber. About three inches back from its tip, the bolt was blocked by an oblong ball of yellow rubber that prevented the projectile from going in too deep and also served to bounce it off the whale.

Mounted on the rubber bow of Hurricane was a metal bowsprit, the "pulpit," custom-made for this work. Each time we closed on whales, I would follow Professor Mate up onto the narrow grate of the pulpit deck. From its holster, which was a transparent plastic tube lashed to the pulpit rail, Mate withdrew the satellite-tag "applicator," a long-barreled, red-metal blunderbuss with a wooden rifle stock. This device, originally a Norwegian invention for shooting line between ships, is powered by compressed air from a scuba tank. The pop is adjustable. For blue whales, Mate sets the dial at 85 pounds per square inch of pressure. For sperm whales, which have very tough skin, he sets the pressure at 120 pounds. Both Mate and I wore waist harnesses, which we clipped into slings on the pulpit rail, freeing up our hands for the shooting.

The first we saw of a whale was almost always its blow.

When the sun was behind us, we sometimes saw a prismatic scatter of color in the explosive expansion of spray and vapor—a few milliseconds of rainbow—before the color shimmered out and the spout faded to white.

Whenever a blue whale surfaced to blow nearby, I was struck by the blowhole—a pair of nostrils countersunk atop the tapering mound of the splash guard, built up almost into a kind of nose on the back of the head. Other baleen whales have splash guards too, but not like this. This nose was almost Roman. It seemed disproportionately large, even for the biggest of whales. Its size explained that loud, concussive exhalation—less a breath than a detonation—and its size explained the 30-foot spout. It was a mighty blow, followed quickly by a mighty inhalation.

The second thing we saw of the whale was its back.

The blue whale is "a light bluish gray overall, mottled with gray or grayish white," as one field guide describes it, and the back is often, indeed, this advertised color, but just as often, depending on the light, the back shows as silvery gray or pale tan. Whichever the color, the back always has a glassy shine. When you are close, you see the water sluicing off the vast back, first in rivulets and sheets, and then in a film that flows in lovely, pulsed patterns downhill to the sea.

If blue whales above water are only putatively blue, then below the surface they go indisputably turquoise. Balaenoptera musculus is a pale whale, and when seen through the blue filter of the ocean, its pallor goes turquoise or aquamarine. This view of the whale, downward through 20 to 50 feet of water, is for me the most haunting and evocative.

If the most beautiful hue of the blue whale is turquoise, then the most beautiful form, the finest sculpture, is in the flukes. In the first week of our tagging efforts, the tail always seemed to be waving goodbye. "Ta-ta," it signaled. "Nice try. Better luck next time." When a whale showed its flukes—when the two palmate blades poised high in the air—we would break off the chase, because elevated flukes meant a deep dive.

But sometimes we saw the flukes close under the surface. They were huge, wider than the boat, and in motion they were hypnotically lovely. "In no living thing are the lines of beauty more exquisitely defined than in the crescentic borders of these flukes," Melville writes inMoby Dick.

The last thing we saw of the whale was its "flukeprint."

When a whale or dolphin swims at shallow depths, turbulence from its flukes rises to form a circular slick on the surface: the footprint or flukeprint. The flukeprints of blue whales are large and surprisingly persistent. The smooth patch lingers long after the whale is gone. "It's a measure of how much energy is in the stroke," Mate told me one afternoon when he caught me staring at one of these slicks. The circle of the flukeprint is perfectly smooth, except for a few faint curves that mark the continued upwelling of energy. Eventually the chop of the ocean begins to erode the slick from the outside inward, but only slowly.

The emphatic flukeprint was another of those discouraging signs that caused us to call off a chase. "Holy smokes!" Mate said one afternoon, as we motored into the middle of a huge one. Ladd Irvine, a research assistant who served as helmsman, laughed in admiration: "We're not going to see him again for a while."

Out on the pulpit, the professor spread his feet for balance, rested the butt of his applicator on the grating of the pulpit deck, and gripped the barrel just below the muzzle-loaded, chiseled tip of his satellite tag. His quick-dry khaki pants luffed and billowed in the sea wind, and now and again the breeze brought a powerful smell of staleness and mold, mixed sometimes with an alarming flatulence. Whew, Bruce! I thought on more than one occasion. Then one day, as the wind rippled in his khakis and we closed in on the spout ahead, the professor emitted a blast so powerful, inhuman, and malodorous that I realized he had to be completely innocent. What I had been smelling, all along, was not our leader. I had been smelling the bad breath of blue whales.

For almost a week at the dome, every whale slipped away from us. On our sixth day our luck changed. We saw three spouts to the southeast that morning and launched Hurricane.

The first two whales toyed with us, as usual, allowing us close, then pulling away. The third allowed us to get in perfect position. We paced the great turquoise shape, keeping abreast of the flukes as the whale coursed along underwater to starboard. As the animal surfaced to blow, it angled up from turquoise abstraction into photo-realism. Irvine gunned the engine. Up in the pulpit I clicked off my crossbow's safety. Mate tucked the rifle stock of the tag applicator into his shoulder, leaned outward over the pulpit rail, and aimed the long, red barrel almost straight downward at the rising whale, now just ten feet underwater. The whale blew, and the glistening wall of its flank erupted in a steep curve above the sea.

My instructions as biopsy guy were to wait for the bang of the tag applicator before firing my crossbow. The smooth flank of the whale filled my whole field of view; there was no way I could miss. At the bang of the applicator, I pulled my trigger. The bolt left the crossbow, and a black hole, small but inky, appeared where I had been aiming. It took a millisecond for me to understand that I was responsible for it, and I felt a pang of regret and guilt. I did that? I thought, like a boy whose pop fly has gone through a stained-glass window.

Then my sense of proportion returned. In relation to the vastness of this whale, my hole was just a mosquito bite. This was not a crime; it was a blow for science. On the pulpit, Mate and I unclipped our harnesses and shook hands.

The blue whale writes a kind of longhand on the surface of the sea. There is the ovoid slick that forms above the head the moment before emergence, the long, narrow slick left by the arching back, and the circular slick of the flukeprint. There are the sputtering white fountains that a blue whale raises by blowing early, still gliding under the surface—a sequence of premature spouts. There are bubble blasts. I saw my first of these just ahead of the bowsprit, about 12 feet deep, as the blowhole of a whale erupted a big bolus of bubbles. It expanded toward the surface, vitreous and glittery, like a crystal chandelier falling upward. "Bubble blast," observed Mate.

This particular bubble blast seemed to be commentary directed at our persistent and irritating little boat—some kind of whale expletive, probably. It rose above the whale's head like a speech balloon in a Gary Larson cartoon. Its message was something like "@*#&%√!?!"

Of all the marks of blue whale cursive, the most colorful was the defecation trail. The first defecation we saw was in a yearling, a little 50-footer. This whale blew 40 yards away, and behind it the ocean brightened in a long, red-orange contrail. "We have a defecation," Irvine announced. This contrail, a brick red streak of processed krill, more watery than particulate, was our first direct evidence that blue whales were feeding in winter at the Costa Rica Dome. As this was one of the hypotheses this expedition had been launched to test, Mate scrambled to find a Ziploc bag to collect a sample.

The evidence for feeding that we observed firsthand in the defecation trails was corroborated in the ship's laboratory. On her computer screen, Robyn Matteson, Mate's graduate student, monitored the echo sounder and the concentrations of krill it detected at the dome. Krill distribution was patchier than anyone had imagined, but dense schools of the small crustaceans were plainly here. Across the lab table, at their own computers, Calambokidis and Erin Oleson of Scripps Institution of Oceanography studied the dive profiles recorded by acoustic tags they had succeeded in applying to several whales. The acoustic tags, deployed by pole and attached by suction cups, stay on the whale for hours, not months, like the more invasive satellite tags. Here at the dome, the depth recorders on the tags showed dives to 800 feet and deeper. The vertical line marking each dive, on reaching its greatest depth, began to zigzag in the sawtooth pattern characteristic of blue whales when lunge feeding on krill.

The evidence for calving at the Costa Rica Dome proved more elusive, but after many fruitless days, it arrived finally, to starboard, by way of a mother and her calf.

The pair were moving slowly, spending a lot of time at the surface. The mother surprised us by allowing her calf to turn toward Pacific Storm. A mother whale often interposes herself between her calf and potential danger, but this mother was an easygoing, Montessori sort of parent, and she let her baby explore.

John Calambokidis drove Squall out to snap surface pictures for photo identification. Nicklin and cameraman Ernie Kovacs grabbed their gear and went along. On nearing the whales, they pulled on their fins and slipped overboard. At first they saw nothing through their dive masks but blue. Then Kovacs, looking for the youngster, was startled to see it pass, maybe five feet below his fins. This whale was just a baby, yet its blue back seemed to pass under him endlessly. The calf, gliding by Nicklin, rolled slightly to bring an eye to bear on him. It peered into the glass orb of the camera housing, and Nicklin's shutter winked back.

After 21 days at the Costa Rica Dome, we could stay no longer and turned north for Acapulco.

On the voyage home, we took stock. There had been disappointments: We wished we had satellite tagged more whales, had seen more calves, had experienced more underwater encounters with blue whales. We were sorry not to have glimpsed whale 4172, the white bull. But for the most part we were satisfied.

In three weeks spent crisscrossing the dome, we had succeeded in finding three whales satellite tagged in California and tracked down here. Each time we homed in on the transmissions of one of these telemetric whales, we had found it in the company of "clean" whales. Satellite tagging had proved itself an efficient method for locating concentrations of the untagged. We had satellite tagged three new blue whales (but one tag failed to transmit), affixed acoustic tags to six more, and photo identified about 70. Thirteen of those 70 were from California. The voyage proved that the dome is visited by large numbers of blue whales. We saw many threesomes, the romantic triangles of the blue whale, and we witnessed much boisterous courtship behavior, all suggesting that the dome is a mating ground. We demonstrated beyond a doubt that blue whales do feed here in the winter. With sonobuoys and acoustic tags, we eavesdropped on A and B calls of the blue whale song and on the D calls whales make between bouts of feeding, and thus began notation of the winter music in this patch of ocean.

The news from the dome is good.

The grandest creature in all creation has been hunted by our kind, the thinking ape, to near extinction. Its numbers still are low, but it was hard not to feel optimistic. In my bunk with Nicklin's laptop, lingering over his dig­ital portraits of the curious calf, I thought I could read, in its strange visage, a gargantuan impishness. I found this cheering. The young do give us hope.

On the voyage home, we found time for reflection, and I understood why the blue whale's flukeprint so mesmerized me each time I saw it at the dome. That big, circular slick is the sig­nature of the species, the John Hancock of flukeprints, outsize and insistent. It jumps out boldly from the parchment. Its uncanny persistence on the sea's surface, defying the choppiness, is a good omen. Appearing at the dome, this winter haven, it suggests that the blue whale might after all defy the chop of history.

"Still here!" the flukeprint says.

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