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Bay
Area Divers
meets the last
Wednesday of
the month.
As always, visitors
are always welcome!
Come on out and
have a good
'BAD' time!
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main Photo Gallery
Whale sharks are harmless to
people and usually indifferent to divers.
Whale sharks are
solitary creatures.
Groups of whale sharks, such as are found in Holbox, Mexico have only rarely been seen.
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The whale shark is a the biggest
shark and the biggest fish. It is NOT a whale. It has a huge mouth
which can be up to 4 feet (1.4 m) wide. Its mouth is at the very
front of its head (not on the underside of the head like in most
sharks). It has a wide, flat head, a rounded snout, small eyes, 5
very large gill slits, 2 dorsal fins (on its back) and 2 pectoral
fins (on its sides). The spiracle (a vestigial first gill slit used
for breathing when the shark is resting on the sea floor) is located
just behind the shark's eye. Its tail has a top fin much larger than
the lower fin.
The whale shark has distinctive light-yellow markings (random
stripes and dots) on its very thick dark gray skin. Its skin is up
to 4 inches (10 cm) thick. There are three prominent ridges running
along each side of the shark's body.
This enormous shark is a filter feeder and sieves enormous amounts
of plankton to eat through its gills as it swims.
The whale shark grows to 46 feet (14 m), weighing up to 15 tons. The
average size is 25 feet (7.6 m) long. It is the largest fish in the
world. Like most shark species, the females are larger than males.
Whale sharks have about 3,000 very tiny teeth but they are of little
use. Whale sharks are filter feeders who sieve their tiny food
through their large gills.
The whale shark is a filter feeder that sieves small animals from
the water. As it swims with its mouth open, it sucks masses of water
filled with prey into its mouth and through spongy tissue between
its 5 large gill arches. After closing its mouth, the shark uses
gills rakers that filter the nourishment from the water. Anything
that doesn't pass through the gills is eaten. Gill rakers are
bristly structures (the thousands of bristles are about 4 inches (10
cm long) in the shark's mouth that trap the small organisms which
the shark then swallows. The water is expelled through the sharks 5
pairs of gill slits. The prey includes plankton, krill, small fish,
and squid. The shark can process over 1500 gallons (6000 liters) of
water each hour.
Whale sharks are solitary creatures. Groups of whale sharks, such as
are found in Holbox, Mexico, have only rarely been seen.
Whale sharks live in warm water (near the equator) both along the
coast and in the open seas. They spend most of their time near the
surface.
Whale sharks are found worldwide in the warm oceans from the equator
to about ±30-40° latitude.
Whale sharks are slow swimmers, going no more than 3 mph (5 kph).
They swim by moving their entire bodies from side to side (not just
their tails, like some other sharks do).
The Whale shark was long thought to be oviparous (an egg 14 inches
(36 cm) long was found in the Gulf of Mexico in 1953; this would be
the largest egg in the world). Recently, pregnant females have been
found containing hundreds of pups, so, Whale sharks are viviparous,
giving birth to live young. Newborns are over 2 feet (60 cm) long.
Whale sharks are sexually mature at 30 years old. This is the age at
which they are able to mate and reproduce.
Whale sharks are harmless to people and usually indifferent to
divers.
It has been estimated that whale sharks may live up to 100 - 150
years.
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COPYRIGHT 2007 BAY AREA DIVERS, ALL RIGHTS RESERVED
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