TO Whale shark is the largest known existing fish on the planet. The whale shark has enormous weight and size, and is a very rare fish that is protected by animal conservation organizations. The fish is very sedentary, slow and does not pose a danger to humans.
Description of Whale Shark
It is simply impossible to confuse this species, because it is huge in size and special appearance. The shark has a thick and powerful body with a flattened head, which is small in size. Closer to the snout it becomes almost flat. The mouth is located at the end of the snout and not under it, and on the body there are 5 gill slits that are about 1.5 meters wide, by the way the mouth is approximately the same size. The eyes are very small and located very close to the mouth, and this explains the shark's not very good vision. So you understand, her eyes are about 5 centimeters, which separate dark side back and white belly of a shark. The size of the shark can reach up to 18 meters, and the largest recorded specimen reached a length of 16.65 m. This species of shark can have up to 15 thousand teeth, which look very small. Even the largest specimen has teeth no larger than 6 millimeters.
This type of shark lives, as a rule, in warm waters low latitudes. They prefer waters where the surface water temperature is at least 20 °C and the water salinity is about 33 ppm. There is evidence that whale sharks have been observed in fresh waters river mouths This may be due to the fact that plankton gather there in large quantities, which constitute the shark’s main diet. Mass concentrations of this type of shark can be observed in June - August, October - November in the area Seychelles near Taiwan. Also permanent places whale shark sightings are southern and south-eastern Africa, Gulf of Mexico, coast of Chile, Australia and Mozambique.
Lifestyle, nutrition and reproduction
The shark itself is inactive and clumsy. Most of its time, it is located near the surface of the water and moves through the water very slowly. The estimated speed of this fish is 5 kilometers per hour. This type of shark, unlike others, takes exclusively plankton as food, and does not pose any danger to humans. The shark's feeding method is very similar to that of whales, which is why it got its name. The shark selects food, which it receives along with water, through a filtering apparatus, which consists of 20 cartilaginous plates. This device is located on the upper part of the roof of the mouth. After this, the strained feed passes through the esophagus into the stomach, and the water is released into the sea. At the same time, you should know that the whale shark can feed on everything that its one and a half meter mouth can absorb. Very little is known about the reproduction of this type of fish, since it is very difficult to reliably study this component of a fish’s life. The main data comes from studies of caught pregnant specimens in 1995. From which it became known that these sharks are ovoviviparous and the caught sample had 307 embryos, ranging from 40 to 60 centimeters in length. Sharks are known to migrate quite long distances. For example, a shark that was tagged in northern Australia migrated 1,800 kilometers in 35 days.
The first time zoologists encountered this species was in 1828. This 4.5 meter specimen was caught in South Africa. Its research was carried out by the famous naturalist Andrew Smith. A stuffed specimen of this fish was sent to Paris, where it remains to this day. An interesting fact is that in 1911, a steamship traveling from England to India carried a 17-meter Whale Shark on its bow for about 15 minutes. Since the shark almost does not react in any way to divers, people who do this take advantage of tourism business. This type of tourist destination is especially common in the USA, Canada and Australia.
Although the whale shark bears the title biggest fish on the planet, still remains practically harmless to humans. She does not have natural enemies, but is constantly on the move, absorbing small fish and other “living dust”.
Description of a whale shark
The whale shark was noticed by ichthyologists relatively recently. It was described for the first time in 1928. Its huge outlines were often noticed by ordinary fishermen, from where fables about a huge monster, living in the sea surface. Various eyewitnesses described her in a terrifying and unsightly form, without even realizing that she was harmless, apathetic and good-natured.
This type of shark amazes with its large dimensions. The length of a whale shark can reach up to 20 meters, and the record weight reaches up to 34 tons. This is the largest-sized specimen that was captured at the end of the last century. The average size of a whale shark ranges from 11-12 meters, with a weight of about 12-13.5 tons.
Appearance
Despite such impressive dimensions, the choice of name was influenced by the structure of her mouth, and not her size. The point is the location of the mouth and the peculiarities of its functioning. The whale shark's mouth is located clearly in the middle of its wide snout, and not below, like many other species of sharks. She is very different from her brothers. Therefore, a special family has been allocated for the whale shark with its own class, consisting of one species, its name is Rhincodon typus.
Despite such impressive size body, the animal can hardly boast of equally powerful and large teeth. The teeth are very small, reaching a length of no more than 0.6 mm. They are located in 300-350 rows. In total, she has about 15,000 small teeth. They hold small food in the mouth, which subsequently enters the filtering apparatus, consisting of 20 cartilaginous plates.
Important! This species has 5 pairs of gills and relatively small eyes. U adult their size is no larger than a tennis ball. Interesting fact: the structure of the visual organs does not imply the presence of an eyelid as such. During an approaching danger, to preserve vision, a shark can hide its eye by pulling it inside its head and covering it with a fold of skin.
The body of a whale shark thickens from the head to the base of the back, forming a raised area in the form of a gentle hump. After this section, the body circumference decreases until the tail. The shark has only 2 dorsal fins, which are moved back towards the tail. The one closer to the base of the body looks like a big one isosceles triangle and larger in size, the second is smaller and located a little further towards the tail. The tail fin has a typical sharply asymmetrical appearance, characteristic of all sharks, with the upper blade elongated by one and a half times.
They have gray color with bluish and brownish inclusions. The shark's belly is cream or whitish in color. On the body you can see stripes and spots of a light yellowish color. Most often they are located in a prim in the right order, stripes alternate with spots. There are also spots on the pectoral fins and at the head, but they are located more chaotically. There are more of them, but they are smaller in size. At the same time, the pattern on the skin of each shark remains individual and does not change with age, which has a beneficial effect on tracking their population.
It is quite interesting that in the tracking process itself, ichthyologists are helped by equipment for astronomical research. There are special devices whose task is to collate and compare images of the starry sky; this helps to notice even minor differences in location celestial bodies. They also effectively cope with the location of spots on the body of a whale shark, accurately differentiating one individual from another.
The sides, to improve hydrodynamic properties, are covered with poorly developed scales. On the belly, the skin of a whale shark is a third thinner than the main layer. That is why, when curious divers approach, the animal turns its back to him, i.e., the most naturally protected part of its body. In terms of density, the scales themselves can be compared to shark teeth, which is provided by a special coating of an enamel-like substance - vitrodentin. This placoid armor is common to all shark species.
Whale shark dimensions
The average whale shark grows up to 12 meters in length, reaching a weight of about 18-19 tons. To put this into perspective, these are the dimensions of a full-size school bus. Just one mouth can reach 1.5 meters in diameter. The largest specimen caught had a girth of 7 meters.
Lifestyle, behavior
The whale shark is a slow-moving animal with a calm, peaceful disposition. They are “sea vagabonds” and little is known about their lives yet. They swim undetected for most of their lives, occasionally appearing off the coast of coral reefs. More often, their diving depth does not exceed 72 meters; they prefer to stay closer to the surface. This fish has little maneuverability; it cannot suddenly slow down or stop due to the lack of a swim bladder and other structural features of the body that provide an influx of oxygen. As a result, he often gets injured when bumping into passing ships.
This is interesting! But at the same time, their capabilities go far ahead. The whale shark is capable of staying at a depth of about 700 meters, like most other shark species.
When swimming, the whale shark species, unlike others, uses not only the tail part, but two-thirds of its body for movement. The urgent need for a regular supply of food forces them to often stay close to schools of small fish, for example, mackerel. They spend almost all their time searching for food, breaking off only for short periods of sleep, regardless of the time of day. They most often drift in small groups of several heads. Only rarely can you see a large school of 100 heads or a shark traveling alone.
In 2009, a concentration of 420 whale sharks was spotted off the coast of coral reefs, so far this is the only reliable fact. Apparently, the whole point is that in August there is a lot of freshly spawned mackerel eggs off the coast of Yucatan.
Every year, for several months, hundreds of sharks begin to circle the coast of Western Australia near the largest reef system, Ningaloo, which borders it. Almost all creatures, small and large, come to feed and breed off the coast of Ningaloo when the reef is bustling with life.
Lifespan
Experts have differing opinions on the issue of whale sharks reaching sexual maturity. Some believe that individuals that reach 8 meters in length can be considered sexually mature, others – 4.5 meters. It is assumed that the animal at this moment reaches the age of 31-52 years. Information about individuals who lived more than 150 years – clean water myth. But 100 is a real indicator of shark longevity. The average figure fluctuates around 70 years.
Range, habitats
To represent their habitat, it is important to understand that whale sharks live in places where food is concentrated for survival. They are also heat-loving animals, preferably choosing areas with water heated to 21-25 °C.
Important! You will not find them north or south of the 40th parallel, most often living along the equator. This type found in the Pacific, Indian and Atlantic oceans.
Whale sharks are primarily pelagic fish, meaning that they live in the open sea but not in great depths ocean. The whale shark is usually found in coastal waters South Africa, Central America And South America. It is often seen close to shore while feeding along reef shores.
Whale shark diet
One of the most important aspects of whale shark nutrition is their role as filter feeders. Teeth don't play big role during feeding, they are too small and participate only in the process of holding food in the mouth. Whale sharks feed on small fish, mainly mackerel, as well as small plankton. A whale shark roams the ocean, sucking a large number of water along with any small nutritious living creatures. This feeding pattern is characteristic of two more species - giant and meter-long pelagic largemouth sharks. However, each feeding process has its own fundamental differences.
The whale shark powerfully sucks in water, then feeds food through filter pads that cover the entrance to its mouth. These filter pads are full of millimeter wide pores that act like a sieve, allowing water to pass through the gills back into the ocean while selecting the desired food particles.
Whale sharks are the most big fish in the world. The length of the average representative of the whale shark family varies between 10-12 meters, however, of course, there are also giants - about 18-20 meters in length. The weight of the world's largest fish reaches an average of 12-14 tons. And a 20-meter individual weighing 34 tons, discovered in the late 1990s, allows scientists to speculate about the existence great variety the size of this animal species.
Despite the fact that most people associate the word “shark” with aggression and mortal danger, which is quite applicable to ordinary sharks, whale sharks are distinguished by completely peaceful behavior and do not pose any danger to humans in this sense. Most often, whale sharks do not notice divers at all, allowing those who are especially daring to touch them. These animals can even give you a little ride, but do not forget that with a blow from their tail, these giants can injure and even kill. However, you won’t be able to take a “breezy” ride, since whale sharks swim at a speed of no more than 5 kilometers per hour. They usually swim closer to the surface of the water, which is the reason for frequent collisions of sea vessels with these animals.
Comparative sizes of humans and whale sharks
Whale sharks are distinguished by their brown or dark gray coloration, which is covered with yellowish or white spots. However, this fish is easily distinguished from others by its colossal size.
Whale sharks feed on plankton and small marine life: They swim slowly with their mouths wide open, after which they close it, release water through 5 gill slits and swallow everything that is left. Great amount sharp and small teeth (in some individuals it reaches 15,000), arranged continuously in several rows, help to hold prey.
The main habitat of whale sharks is the Pacific Ocean and waters Caribbean, however, sometimes they can end up in other warm corners of the World Ocean. Whale sharks, whose population is already small, have become endangered due to the fishermen of the South and South-East Asia who catch this type of fish on a huge scale, without at all burdening themselves with the moral aspects of such fishing. During recent years, even despite a total ban on fishing for whale sharks due to the threat of their extinction, poachers continue to catch them. For this reason, the recovery of the whale shark population is very slow. 
Whale shark, belongs to the class cartilaginous fish, since her skeleton is made of cartilage and not bone.
Whale sharks live in warm temperate and tropical waters. Representatives of this species swim to Florida and California. These sharks are not found near Japan. In the south, these giants do not swim further than Brazil and Northern Australia. The whale shark is not found in the Mediterranean Sea, but it lives in the vastness of the Indian Ocean. Some individuals swim to Africa.
The body structure of the whale shark is similar to other species of sharks. But the whale shark, unlike other members of the family, does not have large teeth with which sharks tear out pieces of meat from the victim. How do whale sharks feed?
Appearance of a whale shark
Whale sharks are considered the most close-up view among the fish. The average body length is 9.7 meters, and individuals weigh about 9 tons.
In 1947, a whale shark measuring 12.6 meters and weighing 22 tons was caught off the coast of Pakistan.
There are many rumors about huge sizes of this type. It is believed that the body length of these giants can reach 21 meters, and their body weight can be 35 tons, but actual evidence has not yet been provided. Most likely, all these conversations are just a consequence of the rich human imagination.
The whale shark has a thick skin covered with placoid scales. The skin on the back is thicker than on the belly. The shark's head is flat with small eyes. The body on top is grayish-brown in color, and the belly is dirty-white in color. The body is decorated with patterns of pale yellow stripes and spots, and each individual has an individual pattern that does not change throughout its life.
This fish has 2 dorsal and pectoral fins. The tail is divided into 2 lobes, its upper part is larger than the lower. This tail is typical for young sharks. And in mature individuals the tail has the shape of a crescent.
Whale shark lifestyle and nutrition
Although these fish have a large mouth, they are not interested in large animals. The width of the whale shark's mouth reaches 1.5 meters. There are 300-350 tiny teeth in the mouth. There are 5 gill slits on each side of the body. These cracks are very important while eating. The whale shark sucks water into its huge mouth along with krill, plankton, small fish and crab larvae. When a shark closes its mouth, its teeth prevent the living creature from slipping out.
Water leaves the mouth through the gill slits. The gills have special valves, in the form of a sieve. Anything larger than 2 millimeters in size comes out through this sieve. The shark swallows this living creature. The smallest living creatures clog the valves; in order to clean them, the fish “coughs”. During a cough, all the little things fly out of the mouth and thus the valves are cleaned.
Whale sharks swim slowly average speed is 5 kilometers per hour. These fish dive to depths of up to 700 meters.
Whale Shark Reproduction
Whale sharks are ovoviviparous, meaning that babies hatch from eggs during birth. The number of cubs can reach up to three hundred. Babies have a size of 40-60 centimeters. After birth, sharks may not eat anything for 2 weeks.
Whale sharks reach sexual maturity at 30 years of age. There is an opinion that there are fewer females than males. But this information has not been verified. Females are larger than males, and they also experience earlier puberty.
The whale shark is a true underwater long-liver. These huge fish live for quite a long time - from 70 to 90 years.
Commercial value and protection from enemies
Whale sharks are subject to commercial fishing. These giants are caught for their liver and meat, rich in shark oil. Today, this shark species is considered vulnerable as its population numbers are steadily declining. Fishermen are trying to catch more major representatives species, and they are usually females. Catching a whale shark is quite easy because, due to its calm nature, it does not offer resistance.
The whale shark was first described by Andrew Smith in 1828, based on a specimen harpooned off the coast of South Africa. Historically, there have been many different names (alternative scientific names) for family, genus and species.
The genus of sharks is now named Rhincodon typus.
Geographical distribution
The whale shark has a very wide distribution range - in all tropical and temperate warm seas, with the exception of Mediterranean Sea. Distributed throughout Atlantic Ocean, from the Caribbean to the shores of central Brazil and from Senegal to the Gulf of Guinea. It is also found in Indian Ocean, including the Red Sea and the Persian Gulf. In the Pacific Ocean it lives from Japan to Australia, from Hawaii to Chile.
Habitat
Unlike most, the shark prefers an open habitat away from the coast. Research shows that this shark prefers warm waters with surface temperatures of around 21-30ºC, with a high density of plankton.
The whale shark is thought to be migratory, but there is currently no direct evidence to support this hypothesis. Its movements may be associated with the presence of a nutrient medium.
Whale sharks can undertake either fairly localized or large-scale transoceanic migrations.
Every March and April, whale sharks are known to concentrate on the continental shelf of Australia's central and western coasts, particularly in the Ningaloo Reef area.
Whale sharks have been observed near La Paz, Mexico. The researchers showed that when these sharks fed at the surface, they swam with little or no head movement, gulping and rhythmically opening and closing their gill slits.
Biology of the whale shark
Distinctive features
A streamlined body and a flattened head characterize the whale shark. The mouth is transverse, very large and almost at the tip of the muzzle. The gill slits are very large. First dorsal significantly larger than the second dorsal fin.
The whale shark has a "checkerboard" color pattern of light spots and stripes on a dark background.
Whale sharks are greyish, bluish or brownish in color, with spots. The belly is white.
One theory for shark coloration is that pigment spots may be an adaptation for radiation protection in species that may spend a significant amount of their time in surface waters and be exposed to high levels ultraviolet radiation.
Teeth do not appear to play any role in nutrition.
Longitudinal protrusions appear on the body along the length of the body; perhaps they are intended to play some role in controlled movement.
The whale shark is the largest living fish. Maximum size 20 m. The smallest adult specimen was found 55 cm in length. Puberty in both sexes occurs after 9 months. It is believed that the whale shark lives on average 60 years.
Whale sharks feed on plankton and nekton, including small crustaceans, schooling fish, and sometimes tuna and squid.
The whale shark feeds actively with its mouth open. By closing its mouth, it releases water through its gills.
During the short delay between the closing of the mouth and the opening of the gill flaps, plankton may become trapped in the dermal denticles lining the gill plates and pharynx.
The fine sieve, a unique modification of the gill rakers, forms a barrier to the passage of all but liquid, retaining for nutrition all organisms over 2 to 3 mm in diameter. Almost nothing except water passes through this sieve.
Coughing has been observed in whale sharks, a mechanism believed to be used to clear or flush out the accumulation of food particles from the gill rakers.
Whale sharks move their heads from side to side, vacuuming sea water, rich in plankton.
The whale shark's small eyes are located on the sides of its head. Because of this, vision may play a much smaller role than smell.
The whale shark is ovoviviparous.
In the past, the whale shark had little interest in humans. Currently, commercial fishing for whale sharks is limited, but the ban may be reduced as demand for food increases.
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