WHAT TO LOOK FOR: A gigantic shark with a broad flat head and checkerboard pattern of spots and stripes on its back.

COLOUR: Dark grey, bronze or greenish grey above with white to cream spots and transverse stripes; white to cream below.

SIZE: This is the largest fish in the world; most individuals encountered by divers range between 18 and 35 ft (5.5 to 10.6m) total length. The largest accurately measured individual was a 39.9 ft (12.19m) male caught off Bombay, India, in 1983. Maximum total length is uncertain, possibly to 60 ft (18m).

TEETH: Minute; the shark strains prey through internal filter screens on its gills.

HABITAT: An epipelagic oceanic and coastal shark of tropical and warm temperate seas. The shark appears to prefer areas where the surface temperature is between 70" and 77"F [21" and 25"C]. The shark is usually encountered near upwellings of cold water 62"F [17"C]; conditions which bring to the surface the plankton and small nektonic organisms on which it feeds. Whale sharks are often seen far offshore, but they also come close inshore and sometimes strand. Divers generally encounter whale sharks at or near the surface.

DISTRIBUTION: Circumgiobal in tropical and warm-temperate seas

BIOLOGY:
Food types - The whale shark is a versatile suction-feeder that feeds on a wide variety of planktonic and nektonic organisms: masses of krill are regularly consumed, along with squid, and small fish: sardines, anchovies and mackerel.
Reproduction - This has been a subject of controversy among shark scientists. In 1953 a very large egg-case containing a 14.5-inch (36 cm] whale shark embryo was brought up in a trawl net in the Gulf of Mexico, which led to speculation that whale sharks are oviparous. It is now thought that the Gulf of Mexico egg-case was an abortion, and whale sharks are ovoviviparous; that is, the sharks hatch from eggs while still inside their mother's uterus, and are born some time later. Newborn whale sharks (so determined by the presence of `umbilical' scars) measuring 21 to 25 inches in length [55 to 63 cm] have been caught in the Pacific Ocean off the coast of Central America, and in January 1996 there was an unconfirmed report that newborn whale sharks washed ashore in the Marshall Islands Newborn whale sharks have also been found in the Gulf of Guinea in the Atlantic Ocean. and in the Persian Gulf.
Life-span - Some species of sharks which live for 100 years, are not able to breed until they are 20 years old and spend 1/5th of their lives evading capture until they can reproduce. Recent studies suggest that male whale sharks are not able to breed until they are about 30 years old. If 30 years is 1/5th of a whale sharks expected life span, it may normally live for well over a century, possibly even 150 years or longer

BEHAVIOUR:
Activity patterns- Solitary sharks have been observed in many areas, but large congregations occur in only a few spots in the world. In the Eastern Pacific many sharks are seen off Mexico from Cabo San Lucas to Acapulco from March to August, and in the Western Pacific there are frequent sightings of the sharks off the Queensland coast in January and February. In the Indian Ocean. whale sharks mass at Ningaloo Reef, northwestern Australia, in March and April when the coral spawn The sharks congregate in Seychelles in August and November but the greatest aggregations appear to occur along the coast of East Africa (South Africa and Mozambique) from October through April.
Feeding - The whale shark is often observed feeding near the surface. Sometimes the shark assumes a vertical posture with its mouth uppermost, then bobs up and down in 15- to 20-second cycles, pausing at the surface to let food-laden water rush into its mouth and strain through its gill plates. There are numerous reports of pelagic gamefish (particularly skipjack, albacore and cobia) swimming with whale sharks; it is thought that the gamefish may prey on smaller fishes that, like the whale shark, are feeding on the plankton.

DISPOSITION:
Whale sharks may be wary of divers and difficult to approach, indifferent, or exhibit curiosity and approach divers closely, apparently to examine them. Danger to Humans - Unaggressive to divers but occasionally bumps a boat that is reeling in a gamefish. Not considered dangerous despite its great size.

TAGGED WHALE SHARKS: Please be on the watch for tagged whale sharks! To determine the seasonal movements of whale sharks, the Shark Research Institute began tagging this species in 1993. To date [2/22/1996] they have tagged 59 whale sharks along the coast of East Africa, and by mid-1996 they will be tagging the sharks in Seychelles. Look for a tag on the shark's back near a dorsal fin. Each tag is 12 inches 130 cm] long, about the same diameter as a pencil, and has an ID number printed on its side. If the ID number has become illegible, remove the capsule at the end of the tag; it also contains the ID number. Notify the Shark Research Institute as quickly as possible; they will want to know when and where the shark was seen, and by whom. [In the USA, you can reach the Shark Research Institute at P.O. Box 40, Princeton NJ 08540, U.S.A. - or by Fax: (609) 921-1505. In South Africa you can reach the Shark Research Institute at P.O. Box 510, Botha's Hill, Natal 3660, R.S.A. - or by Fax: (031) 769-0439, or you can contact them via eMail: SRILevine@aol.com