Megamouth Shark

The Megamouth shark is among the rarest species of shark. Along with the whale shark and the basking shark, it is considered one of the gentle giants of the sea because of its slow-moving nature and non-aggressive behavior towards humans.

The first-ever specimen was discovered relatively recently, on November 15, 1976. This particular megamouth got entangled in the nets of the US Navy ship AFB-14, 25 miles off the coast of Hawai’i. Biologist Leighton Taylor, who examined it, gave the shark its name because of its 3 feet wide mouth.

Description

Size: Length- Males: 13 ft (4 m) Females: 16 ft (5 m)

Weight: 1651.98 lb. (750 kg)

Body and Coloration: It has a stout and cylindrical body, with a long bulbous head and an asymmetrical tail. Megamouths have enormous mouths with 50 rows of teeth in their upper jaw and 75 rows in their lower jaw. The rows of teeth are higher in males than females.

 Its dorsal region is brownish-black, with a white underside and a bright silvery-white upper lip.

Range and Distribution

This rare species was spotted in the depths of the Pacific, Atlantic, and Indian Oceans, with the most sightings observed in Japan, the Philippines, the Hawaiian Islands, and Taiwan. Specimens have also been found in California, Indonesia, Vietnam, Ecuador, Brazil, Senegal, Mexico, Puerto Rico, South Africa, and the continent of Australia.

Habitat

The megamouth shark is a deep-sea dweller, found at a depth of 15,000 ft. Scientists believe that it returns closer to the surface at night to follow its prey.

Diet

It is a filter feeder, drawing water through its open mouth and trapping small species like krill, plankton, copepods, jellyfish, and shrimp.

Lifespan

Because of its rarity, their lifespan remains unknown.

Behavior

• This shark is a poor swimmer and less active compared to other filter-feeding sharks.
• They undergo vertical migration, diving deep during the day and swimming to the surface after sunset.

Predators

Known threats to it include sperm whales and the cookiecutter shark.

Adaptations

• Their reduced teeth size and papillose gill rakers help them in filter-feeding.
• The upper lip of these sharks has a white band that reflects light serving as a feeding mechanismand helping them identify other megamouth sharks.

Mating and Reproduction

They are ovoviviparous, giving birth to live young. Males insert their claspers inside the female oviduct to impregnate them.

Life Cycle

Like many other sharks, these species practice oophagy which means the mother provides their unfertilized eggs for the nutrition of the unborn sharks.

The number of offspring and the gestation period have not been reported so far. The juveniles reach sexual maturity when they reach 13 ft in length.

Conservation Status

The IUCN lists this species as “LC” or “Least Concern”. 

Interesting Facts

• The Megamouth Shark was featured on Discovery Channel’s documentary feature “Alien Sharks” as a part of their annual Shark Week programming line-up.
• The biggest ever recorded specimen to date was caught and released in California.
• Though their exact population in the wild is unknown, as of 2018, 99 megamouths have been sighted.