The megamouth shark (Megachasma pelagios), is a shark that was identified as a new species relatively recently in 1983. Further studies need to be done to learn more about this animal, as various aspects related to their biology, behaviors and habitat are still unknown. As of December 2018, just over 120 individuals have been documented, which has undoubtedly limited studies of the species.
However, it has been possible to know different characteristics of this cartilaginous fish, which turn out to be particular and different from the traits that chondrichthyans generally share.We invite you to continue reading this PlanetAnimal dossier to discover certain characteristics of the megamouth shark.
Origin
- Africa
- America
- Asia
- Oceania
- Australia
- Brazil
- China
- Ecuador
- United States
- Indonesia
- Japan
- Mexico
- Peru
- Philippines
- Puerto Rico
- Republic of South Africa
- Senegal
- Sri Lanka
- Taiwan
- Vietnam
Magmouth Shark Features
The most prominent feature of this shark that gives rise to its common name is its large mouth, which is broadly rounded.As for the body of the megamouth shark, its head is large, its eyes are small, and its snout is extremely short and round. The jaws correspond to this last aspect, managing to open widely but without much lateral distension. This animal has many small hook-shaped teeth that are not functional.
Due to the presence of a rather conspicuous white stripe, present on its upper lip, this animal was thought to produce bioluminescence, which was used as a decoy to feed. However, recent studies have dismissed this idea and established that it is very likely that thanks to the denticles in this band, the animal reflects the light of the luminescent plankton.
The body of the megamouth shark is cylindrical and robust, but tapers towards the posterior region, giving it a tadpole shape. It is flaccid in texture and its coloration is dark brown. The megamouth shark reaches a size of about 5 meters in length and weighs 750 kg.
As for the fins, it has two dorsal ones, which are low insertions and angular. The anal fin is small, while the pectoral fins are long and narrow. For its part, the pelvis is of medium size and the caudal asymmetrical.
Magmouth Shark Habitat
The megamouth shark has a wide range in tropical and temperate waters of major oceans. Although there are limited data on its populations, it is known to exist in greatest abundance in areas such as Taiwan, Japan, and the Philippines, as well as in the central and western Pacific Ocean. Reports indicate that the first specimen captured was in 1976 in Hawaii.
The habitat in which it is found corresponds to the waters of continental and oceanic shelves. It manages to be present at different depths, 5 m near the coast, 40 m on the continental shelf and at much greater depths in the pelagic zone, around 1000 m.
Habits and customs of the megamouth shark
The megamouth shark is not considered a dangerous species for humans because aggressive behavior has not been identified. It is a slow swimmer and so far it is considered a vertical migratory species. That is, it makes continuous movements in this direction. Monitoring of some individuals has shown that during the day they move at depths between 120 and 160 m and at night they rise between about 12 and 25 m.
These vertical movements appear to be related to light levels which affect the feeding of these animals. It is also believed to make deeper dives to escape disturbance, which may be related to the species not being previously known.
Finally, some individuals were seen swimming in surface waters.
Magmouth Shark Feeding
This animal is one of the rare species of sharks to feed exclusively by filter. Despite a large number of rows of teeth in both jaws, they are not functional. It moves at low speed with its mouth open to let in water which it will then expel. But, thanks to the cartilaginous lining it has in the gills, the food is trapped and can be eaten.
The megamouth shark feeds mainly on plankton, krill, copepods, a species of luminescent jellyfish (Atolla vanhoeffeni) and small fish.
Reproduction of the megamouth shark
So far, male megamouth sharks are only known to mature when they are about 4 meters tall. It is an internally fertilized species and due to its mode of reproduction, it is classified as ovoviviparous or viviparous lecithotroph. The embryo after having absorbed the yolk sac, resorts to oophagy or uterine cannibalism, that is, it consumes other eggs produced by the mother.
In some regions, the species can reproduce between October and November and at birth it has a dimension less than 177 cm.
Conservation status of the megamouth shark
The main threat of the megamouth shark is its accidental capture by large fishing boats, so this animal is trapped in various types of nets used by the aforementioned industry. So far, the International Union for Conservation of Nature (IUCN) has listed it as Least Concern and its population trend is unknown. In Asia and Brazil, it is a species traded to be eaten.
As part of the conservation actions, the capture of these animals in the United States has been prohibited, except if they are accidentally captured and in these cases they are given or sold for scientific, educational or exhibition purposes . In countries like Taiwan, there is an obligation to declare the captures of this animal.
Due to the lack of information on the global population and habits of the megamouth shark which indicates a tendency to be easily caught by accident, it is necessary to develop protective actions to avoid future risks which could lead to eventual extinction of the species.
Magmouth shark pictures
