Order: Lamniformes
Family: Megachasmidae
Genus & Species: Megachasma pelagios
APPEARANCE
The megamouth shark's name says it all: it is a shark with a huge mouth.
The head is bulbous with protruding jaws. There are white marks on the tips
of the fins and mouth and a dark triangular mark on the base of the throat.
The average length of the megamouth is 4.5 m (15 ft.), although a captured
female was 5 m (16.6 ft) long. The average weight is 750 kg (1650 lb). The
captured female weighed a whopping 1040 kg (2288 lb). The female had 55
tooth rows on the upper jaw and 75 on the lower jaw. The teeth are small
and used to filter food. The body is flabby and cylindrical and the eyes are
rather small. Megamouths are slow swimmers.
HABITAT
The megamouth shark has been spotted off the coasts of Hawaii, California,
Japan, the Philippines, Senegal, Indonesia, and western Australia in the
Pacific and Atlantic Oceans. It is a deep-ocean creature and comes up to the
surface to feed. They have been spotted in both temperate and tropical
waters of the Pacific.
FOOD
The megamouth shark is a filter-feeder like the whale and basking sharks. It
migrates through the water along with its prey, which is mainly shrimp and
plankton. For example, at 6 pm the megamouth comes up to the surface
where the shrimp swim. At 6 am it follows the shrimp back down into the
depths of 150 ft of water to continue feeding.
ENEMIES
Because the megamouth shark is somewhat of a mystery fish and is
considered the rarest of all sharks, no enemies are known. Because of its size
its enemies are probably very few. However, on August 30, 1998, off the
coast of Indonesia, a boat with WWF Italy volunteers out looking for whales
came across three sperm whales "attacking" a megamouth shark. As they
approached, the whales swam off. The shark was bewildered and evidence of
the assault were clearly shown along the gills and dorsal fin. Whether the
sperm whales were attacking the shark, playing with it, or just curious is not
known.
BREEDING
Little is known about its breeding habits. It breeds sexually through internal
fertilization. The babies are miniature replicas of the parents. The captured
female had several whitish ova measuring 5-10 mm in diameter.
NEW DISCOVERY
The megamouth shark was not known to exist until 1976, when a male got
caught in a US Navy trawler's parachute anchor off the coast of Hawaii. The
discovery shocked the scientific world because before 1976 there was not
even a hint as to its existence. Since 1976, 11 other megamouth sharks have
been spotted, caught, or washed ashore. Only one female has been found.
RELATIVES
The megamouth is the only known species in the family Megachasmidae. It
shares the order Lamniformes along with the mackerel sharks, such as the
great white and basking sharks.