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Guy Harvey

It was my first trip to Belize and I was 35e miles offshore in an open panga with guide Alfred, my 12-year-old daughter Jessica and 9-year-old son Alex, plus some diving buddies from Spain and Florida. Alfred had assured us that if we looked for the transient schools of skipjack tuna and blackfin tuna in the deep off the continental shelf, we would encounter a whale shark. All eyes were scanning the blue horizon and Alfred was first to see the telltale flash of terns wheeling and diving in the sun over a school of feeding tuna a mile away.
 
We raced closer. We just had snorkelling gear and our underwater cameras. 

“We are going to slide up quietly ahead of the bait school and then you guys drop quietly in the water. Let the school of fish come to you, don’t swim at them,” Alfred advised.
 
As we got closer I saw a large dark spot of colour in all the foam generated by the feeding tunas. Next to this were numerous other brown smudges. We were in luck. We all went over the side; I had my video already running as huge shapes loomed in the foam.

What a sight! Adrenaline was pumping! The whale shark was in feeding mode, tail down, head up, angled at 60 degrees, mouth wide open at the surface. All around small tunas beat the surface to froth, and numerous silky sharks cruised waiting expectantly for a stray. The clouds of small sardines were taking refuge from the tunas by crowding around the head of the whale shark, which had its mouth wide open, so the baitfish swam straight into the cavernous gap, and were swallowed by the whale shark. What an ingenious feeding method! I had read about this feeding technique, but never seen it, and here it was going on in front of me like I was in an IMAX movie theatre.
 
Around the 25-foot-long whale shark, about a dozen silky sharks were mimicking the whale shark, heads up, tails down, mouths wide open, as the sardines wheeled and turned to avoid the onrushing tunas. And it worked! Periodically the silkies gulped down a mouthful of small baitfish. One big nine-foot silky peeled away from the group and headed straight for me. Even before it took a shot at the camera, I knew this might happen. The Amphibico camera housing was silver, and in all the drama the shark could mistake it for a disabled tuna. The shark slammed into the housing, pushing me backwards. I retaliated, fending it off, and the shark shied away, to turn again and come by for another look before returning to the melee.
 
The whale shark consumed most of the bait, the tunas moved on to find another bait school and the whale shark ambled past us at the surface, the size of railway car, sunlight dappling on its back as it followed the sound of tunas feeding again on bait. Very cool. We got back in the panga and followed the huge animal and had several more interactions before they all disappeared in response to signals we could not know.
 
Later that afternoon, Alfred took us back to the shelf edge where we dived with the spawning cubera snappers and watched open-mouthed as five whale sharks converged on the ensuing cloud of suspended gametes, passing through the milky water repeatedly with bucket mouths agape, straining the nutritious morsels from the water. The light was getting poor, as it was all taking place at sunset, and we had a long run back to Placencia on the mainland, so we headed in, elated and exhausted from our whale shark encounters.
 
Whale sharks are the largest of all fish, growing to 50 feet long and weighing many tons. They inhabit all tropical oceans across the planet, so are widespread, but are not common. They are slow moving, docile animals that have become a favourite of divers and snorkelers wherever they are encountered and are known to congregate in certain locations consistently to take advantage of feeding opportunities. Generally these are in locations with a high density of plankton, or as I described above where fish species are known to aggregate and spawn in vast numbers. They have wide mouths, tiny teeth, and fine gill rakers that strain microscopic food items from the water, like a giant sardine or anchovy.
 
Their huge size, square head, and white spots all over their body easily identify this amazing animal.
 
They migrate over great distances trying to locate baitfish, which also depend on plankton blooms. They pass by the Cayman Islands and there are occasional sightings reported by divers, but because the waters around us here are poor in nutrients, there is little primary productivity, therefore little plankton and few bait fish, by comparison to the western or southern Caribbean.
 
Whale sharks are slow growing, long lived animals that reach first maturity at 30 years old and may live for a century. Little is known about their general biology, growth rates and reproductive strategy, but occasionally pregnant females have been sampled with up to 300 fully formed pups inside. Whale sharks have not been seen mating, and it is not known where pupping occurs. The Shark Research Institute is beginning to tag whale sharks with archival tags, which will cast more light on their migrations.
 
Small individuals, up to 20-feet-long, have been kept in captivity for long periods in Japan, Taiwan and in the USA, making these unique creatures available to the general public, and aiding in research and educational projects.
 
Whale sharks are exploited in the Indian and western Pacific Oceans for their meat and fins, to the extent that the IUCN has declared them as vulnerable to overexploitation. However in places like Western Australia, the Galapagos Islands, Isla Mujeres, Contoy, and Roatan in the Caribbean, these giant fish show up in large numbers in the late summer to feast on plankton. Here they are targeted by divers who seek the thrilling encounter with the world’s largest fish.
 
But you can meet them anywhere. I was conducting a shoot on white marlin in Venezuela for my TV series, and came across schools of yellowfin and skipjack tuna working big schools of sardines, a phenomenon called a ribazon, and amongst them were some of the biggest whale sharks I have ever encountered, all over 40 feet. Feeding right next to them were 60 foot long Bryde’s whales, charging into the dense aggregations of bait at twenty knots, while the whale sharks appeared to leisurely gulp the sardines head up, tail down and beating to hold the near vertical position.
 
If you are lucky enough to encounter a whale shark while out fishing or diving, take the opportunity to get in the water with these unique, docile, slow swimming creatures. You will be mesmerised by their size and vivid spotted colouration. As long as they stay near the surface you will have an encounter you will always remember. They are truly a magnificent creature.
 
It is our collective responsibility to conserve marine creatures and maintain the biodiversity of the planet.   WH

Guy Harvey PhD.
www.guyharvey.com