The whaleshark is the largest fish in the sea and is so-called because it filter-feeds on plankton and shoals of tiny fish just like the great baleen whales. It s undoubtedly a shark but it's a shark without teeth. A fully-grown whaleshark can be as big as twenty metres long. That's as big as the biggest intercontinental truck. As a species it's not particularly clever either. It simply swims about the tropical zone with its mouth open, constantly feeding and consequently growing bigger and bigger.
The first whaleshark I ever encountered underwater was swimming round and round in circles in the upper reaches of the Gulf of Aqaba in Eilat. It had been captured by the Swedish skipper of a freighter who had simply hooked it with a grapnel anchor at the end of a rope and towed it more than fifty miles. Not only that but when the grapnel came dislodged, instead of escaping the whaleshark allowed the man was able to hook the mighty beast a second time.
You can have a lucky encounter with a whaleshark almost anywhere whilst scuba diving in the tropical zone. In the summer they have often been seen by divers around the reefs of the Red Sea in Egypt. The fact of the matter is that many give birth to their live young in the Gulf of Tadjura in Djibouti and while most animals are believed to then make an anticlockwise migratory circuit of the Indian Ocean, some pass up through Bab-el-Mandeb and head north into the Red Sea instead. They follow the food source, the plankton bloom. It's very much a matter of luck which way they go.
The Mafia Channel in Tanzania is usually thickly green with plankton and while it may cause difficulties with visibility for scuba divers, the whalesharks love it. There are so many animals present that a scientific diver, one Matt Potenski, is devoting his time to fitting radio tags to any he can swim close enough to. Further south they pass by the Seychelles and the owner of the Seychelles Underwater Centre, scientist David Rowat has spent a life-time studying and identifying different animals and writing books about them. He even used a microlite aircraft to go whaleshark spotting in the nearby ocean. They are also regularly dived with near Tofo in Mozambique.
Down in Western Australia, at Exmouth and nearby Ningaloo Reef, a whole tourism industry has grown up around providing people with a snorkeling experience with these spotty monsters and the same could be said of South Ari Atoll in the Maldives. Here the plankton is very deep and the shallower water very clear. It's not certain why the whalesharks come up into the shallows from time to time but they do and when they do it's likely that hordes of people will attempt to swim with them for those few minutes before they descend back down where their dinner is. It's when people discover that although these fishes appear to swim along in a ponderous and relaxed manner a few gentle sweeps of their tales with propel them faster than anyone can swim. Because they are so large they only look like they are swimming slowly. People normally breath-hold dive because scuba equipment causes too much resistance to swimming quickly.
The biggest whalesharks are to be found in the Pacific Ocean probably because they have been left unmolested to feed for a longer interval. Good places to encounter these marine giants include the outer islands of the Galapagos, remote Malpelo, Costa Rica's Cocos Island and Socorro in Mexican waters.
They are also regularly dived with around the Camotes Sea between the islands of Cebu and Leyte in the Philippines. In the furthest Eastern reaches of Indonesia, around the Bird's Head Peninsular of West Papua, whalesharks have developed a symbiotic relationship with the fishermen and they coexist peacefully side-by-side around the fish traps so set up. Scuba divers in Cendrawasih Bay can pay to dive alongside these fish traps too.
There's also a population of whalesharks in the tropical Atlantic and these breed in the warm waters of the Gulf of Mexico. Whaleshark diving expeditions are organized around the Isla Mujeres in the Summer season when there are plenty in evidence. In fact whalesharks are to be found anywhere between the Tropics of Cancer and Capricorn and sometimes well beyond them at the right time of year.
Of course, in some parts of the world these gentle creatures fall victim to fisheries. It's a horrible thing to see one being sliced up on a dockside but it happens notably in Indonesia and South India. Hopefully laws will soon be put in place to protect them.
In the meantime, it's a wonderful experience to swim alongside a creature far larger than you are - especially in the knowledge that it is totally harmless. If you want to dive with one of these ocean wanderers, it's always going to be a matter of luck. However, if you set off to one of the places I've mentioned, and go at the right time of year, you increase your chances of having one of the most memorable experiences of a lifetime!
Happy Diving - John Bantin