Humpback Whales: Tonga and the Silver Bank

Although they are oceans apart, both the Kingdom of Tonga in the South Pacific and the Silver Bank off the Dominican Republic offer intimate encounters with majestic humpback whales.

Surface activity, such as this breach, is very commonly seen on the Silver Bank during the whales’ migration.

The Humpbacks of the Silver Bank
By Stephen Frink

Psychologist B.F. Skinner in his operant conditioning experiments found that pigeons would perform tasks for longer periods if rewards came at random intervals, without predictability. He suggested that "intermittent reinforcement" generated behavior that was most difficult to extinguish.

Now imagine Skinner's pigeons and food pellets replaced by snorkelers and humpback whale encounters. Being in the water with a wild humpback whale is the sort of experience that people go to great lengths to repeat. A week spent seeking encounters with these animals may result in only a few occurrences, and the likelihood of finding an engaged whale is intermittent and not necessarily high. But the reward is substantial. There are few in-water encounters as inspirational as coming eye to eye with a 50-foot whale, especially if it's accompanied by a 12-foot-long, 1,200-pound newborn. Whale aficionados in ever-increasing numbers are repeatedly staging expeditions to the far corners of the world in the hope of having meaningful encounters with these charismatic mammals.

For North Americans, the Silver Bank of the Dominican Republic is a much nearer and less expensive destination for close and intimate humpback encounters than Tonga or French Polynesia. Tonga is about 500 miles west-northwest of Suva, Fiji, which means an 11.5-hour flight from Los Angeles to Fiji and another 90 minutes to Tonga. Contrast that with the two-hour nonstop flight from Miami to Puerto Plata, Dominican Republic (the port of departure for liveaboard trips to the Silver Bank), and you understand the time economies involved in the pursuit of humpback whale encounters.

Other differences between Tonga and the Silver Bank include the water clarity and the way whale encounters are structured (more about that later). Tonga has spectacular visibility, with 100-120 feet a reasonable norm; visibility on the Silver Bank is typically about half that. But the similarities that link the two places are terrific whale encounters and the possibility to achieve proximity in the water.

The Sanctuary for the Marine Mammals of the Dominican Republic
In 1986 the Dominican government designated the Silver Bank as the world's first sanctuary for marine mammals, and in 1996 the government expanded the protected area to 19,438 square miles, which includes nearby Navidad Bank, Mouchoir Bank and Samaná Bay off the eastern shore of the Dominican Republic.

Three dive companies operate on the Silver Bank (under Dominican government permits): the Aggressor Fleet, aboard the Turks & Caicos Aggressor II; Aquatic Adventures, aboard the Turks & Caicos Explorer II; and Conscious Breath Adventures, aboard the Belize Sun Dancer II. Each vessel makes 10 excursions per season, each a Saturday to Saturday beginning in the last week of January and running through the first week of April. Each boat carries a maximum of 18 passengers, so no more than 540 snorkelers per year get to view a whale population that may number in excess of 6,000.

A seasonally resident whale population this massive makes it sound like spouts would dot the seascape in every direction, but the reality is they aren't necessarily all there at the same time, and the Silver Bank is fairly large at 900 square miles. You'll see a lot of whales during your week, but the sightings will be spread out. Some days you may see lots of surface action, while at other times hours might pass between sightings. But whales are there, a lot of them, and we are allowed to swim with them. Therein lies sufficient justification for a trip to the Silver Bank during whale season.

The Silver Bank is a submerged limestone plateau in the North Atlantic Ocean situated between the Dominican Republic and Grand Turk. Depths average 60 to 100 feet, which is why the whales come. The surrounding waters are deep, but the warm, shallow waters here provide protection. During their time at the Silver Bank, pregnant females calve, and females in estrus mate. Testosterone levels in the males are at their peak, and competition for willing females results in amazing surface activity: breaches, lob tailing, fin slapping and peduncle throws in rowdy groups.

These whales have become accustomed to having small dinghies around them — the adult whales may have been born here and have returned every year since. It might be overstating it to say they are desensitized to swimmers in the water though, because proximity is not ensured. But one willing whale can provide the experience of a lifetime, and the odds may be better here than at any other place on the planet.

On the Bank
Our trip began with a relatively calm crossing. We left Ocean World Marina in Puerto Plata at midnight and woke up in the morning to spouts and breaches on the near horizon as we entered the protected waters of the Silver Bank. Not all crossings go smoothly, so those with a propensity for seasickness might consider bringing a scopolamine patch or similar treatment. I had been to the Silver Bank twice previously, but it had been more than a decade ago, so I was surprised when the instrumentation in the wheelhouse displayed a water temperature of 82°F. I remembered low- to mid-70s°F in the past.

The temperature made for a very comfortable time in the water, but for a humpback fresh from packing on blubber in the Antarctic in preparation for a time with no food in the Silver Bank (here they concentrate on procreation and training their young) it might have been a bit toasty this season. But we had a lot of whale encounters, and high-energy ones at that — if the whales were too warm, they didn't complain.

The crew thoroughly briefed us on the protocols for whale interaction, which they referred to as "soft in-water encounters." No scuba is allowed — divers use only a mask, snorkel and fins. We were advised not to swim aggressively toward the whales but rather allow them to approach our group at the surface. By entering the water quietly and floating peacefully as a group, participants minimize disturbance of the whales and allow the animals to choose whether to approach or not. It is an encounter in their environment, on their terms. The guides' years of observational expertise must not be overlooked, however. They have a keen sense of which whales are most likely to accept in-water encounters as well as when divers should enter the water to maximize the chance of such encounters.

It is very rare to have a whale come so close to the skiff that the vessel’s canopy casts a shadow on the whale’s tail, but that’s what happened in this once-in-a-lifetime encounter.

We had several very productive encounters in the water and even more topside. The most magical moment was with a young whale they nicknamed Bart. We came upon him doing a headstand, his tail flukes suspended high in the air. We motored up slowly and then shut down the engines. Bart seemed unfazed by proximity; he swam around our boat, spyhopping for a better view and then performing a few more headstands and giving us all the fluke shots we could possibly want. The guides eventually determined we should try getting in the water, but despite our stealthy entry Bart wasn't interested in hanging out with us in the water — which is typical. Some whales seem to be interested in snorkelers, and others prefer to keep their distance. But once we were back on the boat Bart resumed swimming around us, circling, rolling and doing headstands close by for almost two hours. I have one photo of his massive barnacle-encrusted flukes so near the boat that half his tail is in the shade of the boat's roof. All the more remarkable is that for those two hours the engines were never running; the activity was all of Bart's own instigation. This was one of those very special days at sea that you can never forget.

As the week progressed we had interactions with sleeping adults as well as mothers and calves. Most remarkable of our in-water encounters was a mother with an escort and a yearling calf, a big 25-foot-long baby that repeatedly nuzzled up under its mom's chin. A pair of energetic dancers gave another group of swimmers a short but exciting demonstration of their skills. One day the action was pretty slow, but when the hydrophone was dropped into the water we were amazed to hear a singing whale, apparently just below us on the bottom.

Baby whales are very inquisitive and need to breathe more often than their mothers, so it is more common to encounter them near the surface.

Late in the week some of the guests were treated to one of the best breaching demonstrations in memory, with a mother and calf performing incredibly. The calf breached more than 50 times and the mother 10 times. Of course, I was on the other dinghy at the time — I didn't get a single breach shot all week — but I was enthralled by my friends' images of the encounter.

Their shots were my intermittent reinforcement, leading me to a behavior I have no wish to extinguish. There are more humpback encounters to be had, on the whales' terms, in the Silver Bank. I've already booked my return charter in 2017.

Special thanks to the Ministry of the Environment and Natural Resources for permitting us to photograph humpback whales on the Silver Bank, part of the Sanctuary for the Marine Mammals of the Dominican Republic.

The Eye of the Beholder: Tonga’s Humpbacks
By Douglas David Seifert

Eye contact is perhaps the truest indicator of a genuine encounter with nature. The moment the eyes of two different species meet and regard each other, there is a recognition of a fellow traveler on this planet — a sensation beyond mere observation. To me, the opportunity to look into a whale's eye, which comes largely at the discretion of the whale, has always seemed the only true way to experience the nature of a humpback.

But opportunities to swim with humpback whales are limited. In only a few places in the world is it both possible and legal to swim with them. To legally swim with humpbacks as an organized endeavor, there are only three places to go: the Silver Bank (about 70 miles north of the Dominican Republic and accessible only by a few liveaboard dive operators), certain islands of French Polynesia and a few islands in the Kingdom of Tonga in the South Pacific.

The Vava'u Islands, in Tonga's northern island group, are like those picture-postcard lush, tropical South Pacific islands that used to exist but now reside only in our imaginations. While many island nations have allowed development of high-rise buildings and commercial centers, Vava'u retains its natural beauty with the minimal amount of infrastructure necessary to provide for its tourists and its population of 16,000.

Its high volcanic peaks are covered in palm trees and dense forests. Limestone rock islands cut by wave action are likewise covered in green shrouds of vegetation. Blue waters run through its bays and inlets out to the Pacific Ocean, where small islands and islets stretch as far as the eye can see. It is a place of uncommon beauty.

The Kingdom of Tonga is known as the Friendly Islands, and the Tongan people take this epithet as their personal motto. Their smiles are ever present, making visitors feel like honored guests. Tongans are proud of their country, culture and heritage, and they are delighted that foreigners come great distances to visit them during the season of whales (July through September), when Tonga hosts more humpbacks than any other Polynesian islands. The South Pacific Whale Research Consortium estimates the humpback whale population to be about 2,300 spread throughout Tonga's various island groups, with the Ha'apai group receiving the largest number and Vava'u the second largest.

Humpback excursions in the Ha'apai group are typically done by liveaboard. I ventured out from Vava'u with a well-established whale-watching operation, which proved to be a good choice. Within three hours of arriving at the airport we were on the boat watching a humpback calf breach repeatedly in azure waters framed by sandy islets and picture-perfect skies.

As we watched it became clear that the calf and her mother were moving intentionally along a course they had chosen. They appeared to not want to be any closer to our vessel than they were, so we watched them depart and looked for other whales.

These whales are engaged in a “heat run,” in which a group of males pursues a female in an elaborate courtship ritual.

It was not hard to find other humpbacks. Periodic blows indicated where they were, and we frequently saw breaches at the horizon. The day ended without any in-water activity but with the experience of having seen nearly a dozen whales from the surface.

A few mornings later we were inside the lagoon in relatively shallow water. The bottom was around 80 feet deep, and coral bommies rose here and there to within 20 feet of the surface. We spotted a calf rolling around its mother, who was resting at the surface. We stopped the boat and watched for a while as the mother slowly submerged. Adult whales need to breathe air every 15-20 minutes but can remain submerged up to 45 minutes; calves need to breathe more often — roughly every two to five minutes, depending on their age.

The mother whale was probably tired after her long migration from Antarctica and the delivery of her calf along the way. Since giving birth, she would have had to maintain continuous vigilance over her calf. Shallow, protected waters near islands and reefs provide refuge for fatigued mothers, who must protect their calves from the few predators they might encounter in open sea — such as false killer whales (Pseudorca crassidens), possibly transient orcas and potentially (but not likely) large sharks — while also avoiding groups of rambunctious bachelor whales looking for receptive or vulnerable females in estrus.

Emiko Wu enjoys a close encounter with a humpback mother and calf in Tonga’s clear waters.

I swam out from the boat, slowly snorkeling in low visibility, when a shadow appeared from the scrim of hazy blue-gray. It was the mother humpback, as large as a locomotive — larger than our boat — some 100 yards away. I stopped swimming and just floated. The slight current gradually carried me closer to the mother whale. She was floating horizontally, about 25 feet below me. I could make out her long, white pectoral fins and the outline of her mouth on her broad, elongated gray head. Then I saw the calf.

The calf was peeking out from beneath its mother's chin. It was clearly watching me, using its mother for shelter and nuzzling her for reassurance. Then slowly it rose out from under its mother on the far side from me and swam to the surface in a gentle looping ascent. The calf resembled its mother (though it also reminded me of a large pickled cucumber), and its movements were somewhat awkward and clumsy. It eventually surfaced and arched its back, exhaling a baby whale breath and swimming unhurriedly, all the while keeping an eye on me, the intruder with a snorkel. I didn't move except to smile.

The calf retained its curiosity about me and swam close as it came up for breaths, always remaining at least a body length (about 12 feet) away. Eventually I became aware that the mother was rising toward me. For what may have been a minute or five minutes or 10, the mother and the calf and I — occupying the same small patch of water in a remote South Pacific lagoon — took each other in.

The intimate bond between humpback mothers and their calves is apparent.

Our eyes met through the glass of my face mask and the empty water between us —eyes just seeing eyes. I felt an odd sensation. We each seemed to be reacting with a universal kind of recognition, perhaps an acknowledgment of each other's intelligence. For a brief moment, before we would each return to our radically different lives, we reached across a vast species gap on this strange and complicated planet to connect.

The experience taught me the true meaning of the word "awe" — the real, unmistakable word "awe" that the dictionary defines as a feeling of reverential respect mixed with fear and wonder along with attendant admiration, joy, dread and esteem. Beauty is a close ally of awe, and if there is beauty in this world it is beheld in the eye of a whale.

It is unknown if humpback whales have emotions as complex as ours, but perhaps it is arrogant to think that man alone possesses the richness of life to know love, beauty, poetry, nobility, grandeur and awe. Is it a flight of fancy to entertain the possibility that we share with whales a kindred manner of thought? Anyone spending a magical moment observing the bond between humpback whale mother and calf will have to consider that our interactions with the natural world provide glimpses into depths of experience that defy our understanding but must nonetheless be respected, perhaps even envied.

My encounter with the mother and calf continued with various stops and starts for another two hours, and then it was over. The whales disappeared into their watery world, and I reluctantly returned to mine.

I experienced many more whale encounters during my time in Tonga; all were different, and all were special. It is a better world with animals as majestic as humpback whales living in it. If we humans could learn to focus less on the unimportant things in life and more on the beauty and value in the natural world around us, we would allow these creatures to live in peace, safe from whale hunters, with ample opportunity to interact with us on their own terms.
Humpback Facts
  • Humpback whales can reach 60 feet long and weigh up to 40 tons.
  • Their common name comes from the stubby dorsal fin that sits atop their fleshy back and the way they arch their backs when diving.
  • Their immense pectoral fins are the origin of their genus name, Megaptera, which means "great wing." The species name, novaeangliae, means "New Englander," which likely refers to where they were first identified and scientifically classified.
  • Humpbacks undertake longer seasonal migrations than any other mammal. The whales' lives are cyclical and alternate between a winter season of birth, courtship and reproduction in tropical waters and a summer season of obligatory gluttony at high latitudes.
  • More than other whale species, humpbacks perform dramatic, acrobatic breaches, leaping partially or wholly into the air, landing with tremendous splashes. Scientists believe breaching may be a function of play or is used to communicate over vast distances or perhaps to remove parasites from the whales' skin.
  • In their summer feeding grounds groups of humpback whales hunt together cooperatively, herding schools of small fish using a technique called bubble-net feeding, releasing bubbles to confuse and contain their prey and then lunging with mouths agape through the shimmering masses.
  • Male humpbacks make long, intricate sounds of varying pitch and phrase during the breeding season by forcing air through their nasal cavities. These "songs" typically last 10-20 minutes and consist of several repeating themes or verses; a whale may sing continuously for up to 24 hours. Whales in the same region all sing the same song, which changes gradually from year to year.
  • Humpbacks reach sexual maturity between the ages of six and 10, and females typically bear a calf every two to three years. Gestation lasts about 12 months, and a newborn calf measures 10-15 feet long and weighs about a ton.
  • The average lifespan of a humpback whale is 45-50 years.
  • Each whale's fluke and pectoral fins have a unique pattern that allows for individual identification.
  • Humpback whales have been protected worldwide by the International Whaling Commission since 1966. In 2008 the International Union for Conservation of Nature and Natural Resources (IUCN) estimated the humpback population to be about 60,000 (an increase to about half of the prewhaling population) and lowered the threat level to Least Concern from its previous classification of Vulnerable (1990-2007). However, the IUCN estimated the Oceania subpopulation (which includes Eastern Australia, New Caledonia, Tonga, the Cook Islands and French Polynesia) to be only a quarter of that area's prewhaling numbers; therefore that subgroup remains classified as Endangered.
Explore More
Watch the Jonathan Bird's Blue World webisode about humpback whales, filmed at the Silver Bank.

Check out behind-the-scenes footage of the new IMAX film Humpback Whales, filmed in Tonga.

© Alert Diver — Q2 Spring 2015