Megamouth Shark

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Megamouth Shark

Megamouth sharks were only discovered in 1976 and it was purely by accident. A US Navy vessel snagged a large male in its anchor line and the 14 foot specimen was hauled aboard and later preserved for study - although considerable damage had been done before preservation could occur. The deep water animal was not only found to be a new species, but it also represented an entirely new genus. At the time of their discovery, many people believed that no large shark species were left to be discovered and the megamouth was a shock to the scientific community.


Content List

1. Scientific & Common Names

2. Characteristics

a. Breeding

b. Behavior

3. History

4. Present Status

5. References


Scientific & Common Names

Kingdom - Animalia

Phylum - Chordata

Class - Chondrichthyes

Subclass - Elasmobranchii

Order - Lamniformes

Family - Megachasmidae

Genus – Megachasma

Species – Megachasma pelagios

Common Names – Megamouth Shark


Characteristics

Megamouth sharks are poor swimmers and they lack the sleek muscular look of many other large sharks. They can reach sizes of up to eighteen feet and weigh over 2600 pounds. Their mouths - true to their name - are large and can be over four feet across. While the mouths are huge, they have tiny teeth in fifty rows with only the first three rows actually functional. They seem to prefer warmer waters but have been found in both the Atlantic and Pacific Oceans.


Breeding

There is very little that is known about how megamouths breed or socialize. They are ovoviparous, which is when the embryos develop within eggs kept in the mother's body. Once the young emerge from their mother, they must fend for themselves as with all other sharks.


Behavior

Like the better known and faster swimming whale shark and basking shark, megamouths are filter feeders and consume plankton and small fish, although evidence from necropsies indicate that small shrimp are their primary prey. They stay at deeper depths during the day and come closer to the surface at night in what is known as vertical migration. They have been observed with wounds inflicted by cookie cutter sharks and one encounter was witnessed where a megamouth was attacked by sperm whales. Little more is known of their habits and behavior since so few have been sighted and video footage is rare.


History

Megamouth sharks are still a mystery on many levels. They have only been known to science since the 1970's but it is likely that humans have encountered them before that sighting. Fossils now believed to be from an extinct megamouth species were found before the 1976 discovery but they were not associated with the modern species for decades. Sharks have a long fossil history dating from 450 million years ago, predating dinosaurs. Today, there are nearly five hundred recognized species of shark with more still to be discovered.


Present status

Only 60 specimens have been observed since their discovery in 1976 so it is impossible to know their conservation status. Most specimens have been accidental by catch, but they are consumed in some areas. They are not red listed and are only categorized as Data Deficient.


References

International Union for Conservation of Nature and Natural Resources (IUCN)

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

Deep Sea News March 10, 2014 by Douglas Long

Fossil Shark Teeth of the World by Joe Cocke

The Book of Sharks by Richard Ellis

The Shark Handbook: The Essential Guide for Understanding the Sharks of the World by Dr. Greg Skomal, Nick Caloyianis(Photographer)

The Encyclopedia of Sharks by Steve Parker

Sharks: History and Biology of the Lords of the Sea by Angelo Mojetta