SHARKS!

from The Shark Almanac
by Thomas B. Allen

Whale Shark (Rhincodon typus)

The largest shark and the largest fish in the sea, the whale shark was a mystery to science until 1828, when Dr. Andrew Smith, a surgeon to British troops in South Africa, bought the hide of a fifteen-foot shark from local fisherman and sent it to the National Museum of Natural History in Paris. Thus the whale shark, long a creature of myth, became a scientific reality.
The whale shark usually feeds on crustacea and tiny fishes drawn into its enormous mouth (see color insert). "Swimming slowly at the surface toward a dense ball of plankton or anchovies, it speeds up and opens its mouth as it nears the target," Dr. Eugenie Clark, the shark researcher, writes. "As it swims through the massed food, moving its head from side to side... it sucks in all or part.... Sometimes the shark will come almost to a stop, hanging with its tail down and pumping up and down in the water as it sucks in food...." It has as many as 15,000 tiny teeth, packed into rows that run along the inner surface of each jaw, just inside the lips. The teeth are not used for biting or crushing food but for holding whatever is scooped into the mouth.
As the whale shark swims, a steady current of water passes into its mouth and out the long gills on either side of its head. As the water flows through the gill slits, it is strained by gill rakers so that food particles are swept into the mouth. The food must be small because the whale shark's throat is very narrow and makes an almost right angle turn to the stomach.
Whale sharks have been observed eating vertically, plunging up and down through schools of small fish. Sometimes during these eating excursions, a whale sharks enormous head breaks the water and fish are seen frantically swimming in the shark's mouth. Tuna feeding on the small fish can be scooped up -- some escape, but others are trapped and the whale shark manages to consume them.
Because of their enormous size, whale sharks are almost impossible to weigh accurately. In 1912, a whale shark thirty-eight feet long was caught off Knights Key, Florida. Dr. E.W. Gudger, who made a lifelong study of whale sharks, measured the shark and estimated its weight at 26,594 pounds, based on his formula: Multiply the length in inches by the square of the girth in inches (216) and divide by 800. After this scientific examination, and enterprising promoter skinned the shark, had it stuffed, and toured the country with it, billing it as "The Only Creature of the Kind in the World."
Gudger believed that thirty-two feet was about the average length of the whale shark and that it could reach a length of seventy to seventy-five feet. A whale shark caught near the mouth of Havana Harbor and weighed piecemeal was approximately nine tons. Its heart weighed forty-three pounds and its liver 900 pounds.
Numerous collisions between ships and whale sharks have been recorded in ship logs throughout the world. It happens often enough to be a recognized maritime hazard. The U.S. navy Hydrographic Office devoted the entire back of its June 1948, issue of Pilot Chart of the North Pacific Ocean to record collisions between ships and whale sharks. Here is one account of a schooner's collision, near Cape San Lucas, at the tip of Baja California:

The vessel was struck on the starboard side by an immense shark. The wheel was wrenched out of the hands of the man at the wheel. The tail of the fish rose 8 feet above the rail of the ship and about 14 feet above the waterline. The engine was stopped [since] the fish struck the propeller. The fish was distinctly seen when it went astern, was a mottled color and was at least 30 to 35 feet long. After going into drydock it was found that considerable damage had been done to the hull and rudder of the ship.

Whale sharks are amazingly docile. Conrad Limbaugh of Scripps Institution of Oceanography was once with a group of divers who happened upon one. "We clambered on the shark, looking it over closely, even looking into its mouth," he reported. "It showed no signs of concern except when we bothered its face. Then it slowly dived out of sight. But it would return to the surface, and we would climb aboard again."
Little is known about the whale shark's breeding habits. In 1910, a female examined in Ceylon had sixteen egg cases in one of her oviducts. In 1955, J.L. Baughman of the Texas Game, Fish and Oyster Commission reported the discovery of an egg case, 27 inches long by 16 inches wide, in 31 fathoms of water 130 miles south of Port Isabel, Texas. The egg case contained an embryo of a whale shark, identified by the conspicuous checkerboard pattern of white dots and bars on its back. Baughman's discovery showed that the whale shark brings forth its young in egg capsules.
Whale sharks are pelagic in the tropical seas of the Atlantic, Pacific, and Indian Oceans, usually in a worldwide range roughly between 30 degrees north and 35 degrees south. But they have been caught as far north as Long Island, New York, and one collided with a ship about 380 miles east of Cape Cod, Massachusetts.
An ecotourist industry has sprung up at Ningaloo Reef on the northwest coast of Western Australia, the biggest marine park in the country. Whale sharks aggregate here in large numbers from March to late April. Divers snorkel with these sharks at Ningaloo. Scientists there are studying the sharks' behavior from data collected by acoustic telemetry and tagging.
Japanese fisherman call the whale shark ebisuzame, a good-luck symbol (and thus immune to being fished), which the fisherman try to avoid killing.
Whale sharks also gather in the Seychelles in August and November. Many whale sharks are seen off East Africa, but the greatest concentration of the sharks appears to occur off Mozambique and the northern coast of South Africa, from October through March. Ninety-five whale sharks were observed in a 68-mile stretch of water between Durban and Umtentweni, South Africa, on a single January day in 1994, during an aerial survey conducted by the Shark Research Institute. Large numbers of whale sharks have been seen off Mexico, from Cabo San Lucas to Acapulco, from March to August, and there are frequent sightings of the sharks off Australia's Queensland coast in November and early December. Newborn whale sharks have also been caught in the Gulf of Guinea in the Atlantic Ocean, and in the Persian Gulf.
Maximum known size: 60 feet, according to the estimate of a whale shark caught in the Gulf of Thailand in 1925. Largest accurately measured whale shark: 40 feet, 7 inches; caught in Bombay, India, in 1983. Its mouth was 4 feet, 6 inches wide, and its pectoral fins were more than 6 feet, 6 inches long.
Distribution: Tropical and warm temperate waters throughout the world.
Danger to humans: Not aggressive to divers but occasionally bump boats that are reeling in game fishes. Not considered dangerous, despite its great size.

"My wish is to ride the tempest, tame the waves, kill the sharks. I will not resign myself..."
-- Trieu Thi Trinh

"There are 350 varieties of shark, not counting loan and pool."
-- L.M. Boyd

"I want you to know that the Shark, being very old and suffering from asthma and heart trouble, was obliged to sleep with his mouth open. Because of this, Pinocchio was able to catch a glimpse of the sky filled with stars, as he looked up through the open jaws of his new home."
-- Carlo Collodi

BACK.