by Tim Harry

Created on: May 19, 2010

The Megamouth Shark, Megachasma Pelagios, is one of the more recent additions to the shark family, having been first recognised as a new species in 1976. The discovery of new life on Earth occurs everyday, although these discoveries tend to be beetles and insects, and nothing quite the size of the Megamouth Shark.

The first confirmed specimen of the Megamouth Shark was found in the nets of a US Navy vessel seeking to recover dummy torpedoes from a testing zone off of the Hawaiian island, Oahu Island. It was quickly recognised as being a previously unclassified species of shark, but it wasn’t until 1983 when a second specimen was discovered off of California.

The discovery of a new species of course means that a new name must be given to it. The scientific name, Megachasma, was given in reference to its defining feature, its large chasm of a mouth. Giving the Megamouth Shark a name is one thing, but researching and finding out about it is another. Since 1976 only eleven Megamouth sharks have been caught or washed up, with a further forty or so sightings of the shark, leaving the possibility of research limited.  

Some suppositions are possible based on evidence collected, but it may well be that future discoveries change many of the assumptions made about the Megamouth Shark. The man distribution of the Megamouth Shark appears to be around the Pacific and Indian Oceans, with the majority of sightings and captures occurring in these waters. The fact though that the Megamouth Shark is a shark that lives in the deepest waters, and the fact that one specimen was caught in the Atlantic Ocean, could mean that the shark has a worldwide distribution.

The Megamouth Shark is distinctive in appearance with a long head and very large mouth. The shark is a normal shark grey colour, with a soft, slippery skin. Size wise the Megamouth Shark is one of the largest known sharks with known examples ranging in the region of 5m in length, suggesting that larger examples may exist. 

The large mouth is adapted for eating, and although it has small teeth, it is the photophores, light emitting organs that are most useful. These organs would appear to assist in the attraction of their preferred food, plankton and shrimp. Studies of the movement of the Megamouth Shark have shown that it travels during the day between depths of 300m ad 1100m, before rising to shallower depths during the night. This is indicative of the fact that the shark is following the migration paths of the shrimp. The plankton and shrimps are eaten via filtering; this means though, like the basking shark, the Megamouth Shark is harmless to humans. There is some evidence that the Megamouth Shark also feeds upon some fish.

There is so much that is unknown about the Megamouth shark that there is hardly anything known about the numbers of the shark in the oceans, or even its reproductive methods. The size of the Megamouth Shark would suggest that it has few predators, although the depths of the oceans are unknown. Indeed it is only the Sperm Whale that has ever been observed to attack a Megamouth Shark.

With so much unknown scientist are of course hoping to be able to learn much more. Most people would hope that this was something that occurred in its natural environment, but the habitat of the Megamouth Shark probably ensures that only those caught up in nets are going to help the scientists.

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