After 1976, it became clear that in the world now there are not two, but three species of shark feeding on plankton. The first two are the whale shark and the giant shark, and the third is the bigmouth shark. The legends and myths of many coastal peoples keep the stories of people meeting with huge sea monsters. Among them there are also references to a large fish: half-kite-half-shark. On November 15, 1976, a fabulous legend came to life: one of the American ships pulled an amazing shark with a huge mouth from the depths of the sea.
Let's take a closer look at it …
The discovery happened on November 15, 1976, quite by accident, when a US Navy survey ship was conducting its research in the Hawaiian Islands. On that day, the ship was above a depth of 4,600 meters and therefore could not release an ordinary anchor. We decided to lower 2 parachute anchors. After the end of the research, when they were raised, they found in one of them an unusual fish of huge size. It turned out to be a 446-centimeter largemouth shark, whose weight reached 750 kilograms. This giant fish was donated to the Honolulu Museum.
After a careful study of the animal, it became obvious that this is a shark unknown to science, which was given the name pelagic largemouth shark (lat. Megachasma pelagios). Why "big-mouthed" is clear to anyone who has seen her at least once in photographs: a round head with a mouth of incredible size immediately catches the eye. But it became "pelagic" due to its habitat - it is believed that these sharks live in the mesopilagil zone, i.e. at a depth of 150-500 meters.
Everything, for some time about this shark there was no more rumor or spirit. But after 8 years, she again made itself felt. The second largemouth shark was caught off Santa Catalina Island (California) in November 1984. This copy was sent to the Los Angeles Museum of Natural History. And then a whole series of similar finds began.
Over the next 30 years, scientists have managed to examine less than three dozen specimens.
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In the period from 1988 to 1990, 4 more sharks were discovered (1 - on the coast of Western Australia, 2 - on the Pacific coast of Japan and 1 - in California), in 1995 - 2 more specimens (near Brazil and Senegal). And so on until 2004. In total, between November 1976 and November 2004, about 25 specimens were observed, the largest of which was a shark, found dead in April 2004 on the coast near the city of Ichihara in Tokyo Bay. Its length was 5.63 meters. It was a female. The smallest shark was a male caught on March 13, 2004 near about. Sumatra. Its length was 1.77 meters. Another specimen was caught by Filipino fishermen in 2005.
The most prominent part of this shark's body is its incredible mouth size. The color is not much different from other types of sharks - dark gray or dark brown. The belly is much lighter than the back.
Since all sharks belong to the class of cartilaginous fish, it was no exception. The skeleton of the bigmouth consists of soft cartilage, and the tissues are highly saturated with water. As a result of this, the shark is not able to develop decent speeds when swimming, so its approximate speed is only about 2 km / h.
At the very beginning of the article, we already mentioned the specifics of her diet. The main food of the bigmouth shark is plankton (crustaceans, jellyfish, etc.), of which the reddish crustaceans euphausiids, they are also krill, living at shallow depths, are especially preferred. A large-mouthed shark, having stumbled upon a school of krill, opens its mouth and sucks in a large volume of water and, pressing the tongue to the palate, squeezes the water out through closely spaced gill slits. The krill escape is covered by numerous small teeth. Having drained the water, the shark swallows everything that is left in its mouth.
Despite the fear of the terrible word "shark", this species does not pose a danger to humans. The big-mouthed shark is especially fond of krill, descending after it to 150 meters in the daytime and rising to 15 meters at night. In any case, this was the behavior of the bigmouth male, which was caught in 1990. Scientists made a film about him, equipped him with a radio transmitter and released him to observe his migratory behavior for almost two days.
Just over 30 years have passed since the discovery of this wonderful fish. During this time, biologists were able to recognize only a small part of the life of the bigmouth. Shark lives in all oceans, with the exception of the Arctic. Most common in the southern hemisphere of the globe. Frequent encounters with fish took place near the Japanese islands and Taiwan, which led scientists to assume that the bigmouth is inclined to warm waters. Also, specimens were caught near Hawaii, Ecuador, South Africa and Australia, which confirms the hypothesis of "thermophilicity" of the animal.
Mating, according to biologists, takes place in the fall off the coast of California, because it was there that most sexually mature males were found. Like many other sharks, the bigmouth shark is ovoviviparous.
A huge mouth with numerous small teeth.
The shark's head has a huge mouth, thanks to which it got its name. With its mouth, it filters the water, leaving only plankton in its mouth, which it feeds on. Since plankton is predominantly found in the upper layers of the water, it may seem that the fish is floating on the surface, but this is not entirely true. Fishermen also fished bigmouths at depths exceeding 200 m. Such vertical migration is common for planktivorous animals that move in the water column following their food.
According to unconfirmed reports, it is believed that the bigmouth shark can live at depths of 1 km. The body structure characteristic of deep-sea inhabitants can serve as a proof of this hypothesis. It is soft and flabby, and the mouth is surrounded by photophores that can serve as bait for small fish and plankton. The presence of photophores is generally characteristic only of deep-sea fish.
The shark swimmer is not important. The bigmouth shark moves at an average speed of only 1.5-2 km / h. The body is dark, brown-black above and white below. In color, it resembles a killer whale, so sometimes observers could mistake a bigmouth for a young killer whale. This is also facilitated by the presence of small teeth in the mouth of the shark.
At the moment, the pelagic bigmouth shark is an almost unexplored animal. Too few individuals have caught the eye of researchers, because it is not so easy to dive into the depths beloved by the bigmouth. For the same reason, it is not known whether the species is threatened with extinction. The mighty ocean keeps its secrets securely.