Sawfish: description and facts about a little-studied fish. Saw fish - the most interesting facts

The biological name of the sawfish is the common sawfish, the family is stingrays, the class is cartilaginous. It can be found in coastal areas, shallows, in algae, sandy soils, near artificial reefs, piers, bridges, estuaries, sunken ships, and almost never deep in the ocean. It is found in such relatively shallow water that its fins protrude from the surface of the water.

Sawfish (lat. Pristidae)

Off the Florida peninsula, residents can see fish year-round. The Australian sawfish ray has become perfectly accustomed to freshwater. Species living off the coast of the American continent migrate north in the summer season, and south in early autumn.

Scientists know seven species of sawflies:

Its habitats:

Atlantic, Indian, Pacific oceans;
Mediterranean Sea;
sometimes − large rivers.

They like any water: salty, fresh, brackish; they are unable to survive only in polluted places. Maximum time the ramp is at the bottom. The turbid environment is its usual place of hunting and rest. Adult individuals prefer a depth of 40 m, where small ones do not swim. Waking time is at night.

What does a fish look like?

Characteristic distinctive feature sawfish - the presence of a bony rostrum with leathery teeth on both sides, resembling a saw. The number of pairs of serrations depends on the type: 14–34. The length of the growth reaches 20% of the body length.

The fish has two fins on its sides, a pair on its back, and one on its tail. The tail merges with the body, in some varieties it branches into two lobes. There is no spine on the caudal fin, unlike the structure of the common stingray, and the body of the fish is covered with placoid scales.

Her average value is about 4.5 m with a mass of 300 kg, large individuals reach 7 meters, and the record weight is 2.4 tons. The length of the toothed process, tapering towards the nose, is about 120 cm in adult fish.

The skin of the stingray is dark olive or another shade, and the belly is light, almost white. On the abdomen, two gills and a mouth opening create the appearance of a tearful face. His body is more flattened compared to the saw shark. The eyes have miniature squirters, through which the stingray pumps its gills and is able to remain motionless at the bottom. It does not have a swim bladder, like elasmobranchs, and buoyancy is maintained thanks to the liver, enriched in fat.

Differences from a shark

Sometimes the sawfish resembles a saw shark, but is also half the size. Shark − cartilaginous class, but it belongs to the saw-bearing family. The appearance of the saw shark is indicated by the Jurassic and Cretaceous periods, and the existence of the saw-tailed ray occurs 60 million years later, with the end of the Mesozoic era.

External differences:

size: 1.5 m versus 6 m slope;
location of the gills: on the sides, at the sawfly they are below;
the shape of a shark’s fins is streamlined, while in a stingray they are clearly defined;
narrowing of the shark’s outgrowth in comparison with the uniform width of the stingray;
regeneration of denticles of the first, in contrast to the second variety;
The stingray does not have antennae on its snout;
The shark moves in sharp jumps, and the saw-tailed ray moves in smooth wave-like movements.

Nutrition

The diet of sawflies includes small invertebrate animals, inhabitants of sandy and silt surfaces, small fish, herring, mullet, crustaceans. It is for this purpose that its saw-toothed part of the body is used: to lift upper layer soil in which the inhabitants of the bottom are located and swallow them.

The so-called rostrum is endowed with electroreceptors that are sensitive to the movement of prey. Such sawfly susceptibility allows you to receive a three-dimensional image of everything that is happening even in cloudy water and orient yourself to attack prey or protect yourself from crocodiles, sharks, and marine mammals.

The sawfish is also capable of wielding its killing weapon like a saber, penetrating schools of small fish. When the affected victim sinks to the bottom, it becomes food for the predator. Sometimes sawflies hunt large individuals, tearing out pieces of meat from them with their teeth.

Reproduction

The sawfish does not lay eggs; it reproduces by ovoviviparity. Over the course of five months, the embryo develops in the body of the mother, feeding on the yolk, and is born wrapped in a skin membrane. The female is capable of giving birth to up to twenty cubs. Their serrated processes during intrauterine development soft and acquire density only over time. The saw shark gives birth in a similar way. The sawfish's lifespan is about 80 years. Puberty occurs relatively slowly, only by the age of 20. Some species of sawfish are capable of reproducing by partogenesis, without the participation of males: in this way, the missing number of fish in nature is replenished. The appearance of newborns has exact copy mother.

Danger to humans

The saw-tailed ray is not dangerous for humans; when it encounters a person, it hurries to hide. But several have been recorded in the Gulf of Panama deaths due to stingrays. It is believed that similar incident sometimes provoked by a person. An unprovoked attack was recorded on the south coast Atlantic Ocean. Unintentional injury is possible if you step on a stingray basking in the sand of shallow water.

Value

In an industrial sense, sawflies are not particularly popular. Their meat is rough, although edible. A good ingredient for soups is their fins. Liver fat is valuable in folk health recipes. A rostrum cost equal to 1000 dollars, which is common in the trade of valuables. The saw shark, unlike the sawfish, has unique taste qualities and is considered a delicacy in Japan.

Some peoples consider it an advantage to have a sawfish decoration at home, others even invent weapons from it, not caring about the extinction of the species. There are peoples who rostrum of sawfly serves as a means of protection against spirits and diseases. On a German submarine, the sawfish served as an emblem; among the Aztecs it was a symbol of the “earth monster” and a symbol of the central bank of West Africa.

The peculiarity of the body structure of fish is the reason that the stingray, like the saw shark, gets very entangled in nets and is damaged by fishing devices for catching. Many sawfly species are disappearing due to pollution waters and are listed in the Red Book. Population numbers have dropped to 10% of their original levels. Since 2007, international trade in sawflies has been banned. It is allowed to catch smalltooth sawfish for keeping in a public aquarium for the purpose of preserving the species.

Some Marine life got their names thanks to external resemblance with some objects, things or tools. For example, a fish is a saw: the photo shows that the head has a long, wide outgrowth, very similar to a double-sided saw (hacksaw), which is well known to skilled people.

Two groups have this unusual “detail” on the front of the head. cartilaginous fish– sharks and rays. But the name “saw” was assigned specifically to saw-tailed rays, and this article contains information only about these fish. About sawnose sharks and detailed description how to distinguish them from saw-tailed rays.

Order Sawtooths

Among Cartilaginous fish there are two superorders, one of which is. It distinguishes groups - squads. The Sawtooth-like order is very original due to its elongated snout, which looks like an elongated rectangle with large sharp teeth along the perimeter. In this small group there is only one family called Sawfishes (Pristidae), known as sawfishes. There is only singular gender, including seven species.

Sawfish can be found in the subtropics and tropics of all oceans. Habitats for different species can be not only sea waters, but also fresh water bodies (for example, the Australian sawfish constantly lives in the river). Among them there are euryhaline species that feel great in both salty and fresh water. Thanks to this feature, these fish enter rivers from the sea, rising quite far upstream.

Appearance Features

The sawfish, the photo of which you see below, has a flattened body, but its shape is very similar to:

the body is equally elongated;
the tail is practically not separated from the body and is its continuation;
there are two large tall ones dorsal fin;
in some species the caudal fin has two lobes;
The skin is covered with placoid scales.

It is especially easy to confuse a sawnose ray with a sawnose shark. To prevent such confusion from happening, you need to pay attention to the abdominal part of his body. Here there are gill slits, which are located in two rows in front of each pectoral fin on the right and left. The slit-shaped mouth and two nostrils in front of it (often mistaken for eyes) are very similar to the "face". But the real eyes of the sawfish are located on the upper (dorsal) part of the body. They are small, and behind them there are sprays, thanks to which water is pumped through the gills, which allows the sawfish to remain at the bottom almost without moving.

These stingrays do not have a swim bladder, and a liver rich in fat is used to maintain buoyancy.

The pectoral fins are wide, wing-like. They are fused with the head and play an important role in the stingray's swimming (by making strokes). There is no anal fin. The dorsal side of the body is colored dark color, and the abdominal one is light. Sawfish rays are large fish and can reach more than 7 meters in length (European sawfish), and the smallest of them (Queensland sawfish) is only 1.4 meters. Now you have a good idea of what a sawfish looks like. Sawfish live up to 80 years.

“Saw” and its functions

The saw-tailed ray uses its unusual tool for two purposes:

detect potential prey;
and catch her (stun and immobilize).

A special feature of the structure of the “saw” (scientifically it is called “rostrum”) is the deep and strong fastening of its teeth in cartilage tissue rostrum. If one of the teeth breaks or is damaged, it will never grow again. Saw-nosed rays of different species have from 14 to 34 pairs of teeth. They all have the same size.

All sawfish rays are divided into two conditional groups: one has large saw teeth, and the second group has small teeth. The sawfly also has teeth in its mouth, but they are small in size.

Rostral teeth and protection from enemies

The rostral (located along the edges of the rostrum) teeth of the sawfish are not teeth, but modified placoid scales, found only in cartilaginous fish (the structure of such scales is actually a little similar to teeth).

The long rostrum, armed with sharp, strong “teeth,” is a powerful tool not only for obtaining food, but also for protection from enemies. Swinging this cutting and piercing tool from side to side, the saw-nosed stingray successfully defends itself.

His natural enemies in the sea there are sharks and aquatic mammals, in the rivers there are crocodiles. After all, some species (for example, the European sawfly) enter rivers and can remain there for a long time. Observations of stingrays kept in aquariums also indicate the use of the “saw” for protection.

Electroreception and prey search

We continue to get acquainted with the formidable “weapon” of the saw-tailed ray – its elongated rostrum-saw. On the surface of the “saw” there are numerous electroreceptors that help find food objects in muddy water, the same way they do it. Ampullae of Lorenzini (organs that capture electric fields from animals) in large quantities are located on the upper surface of the rostrum. This makes it possible for the sawfish to receive information about living objects that float in higher layers of water above it and often become its prey.

Sawfish rays do not feed big fish and various invertebrates living in the soil.

With their flat saw, saw-tailed rays dig the ground to extract burrowing invertebrates, most often these are mollusks and crustaceans. Sometimes they use the saw as a saber. Bursting into a cluster of small fish (mullet or sardines), the stingray swings its weapon and hits the prey, which falls to the bottom. Having descended after the struck victims, the sawfly swallows them.

Lifestyle and biology

The primary habitat of sawfish is shallow waters. The depth is sometimes so shallow that both high dorsal fins of the stingray lying at the bottom stick out above the surface of the water. U American shores The saw-throat ray is a migratory species and makes massive seasonal movements: in the summer from southern to northern waters, and in the fall they return to the south again.

All sawflies reproduce by ovoviviparity. Embryos develop in the mother's body, being in the egg and feeding only on the yolk, in contrast to, and, whose embryos receive part of their nutrition from the mother with the help of special formations that are vaguely similar to the placenta of mammals. On average, females of different species give birth to from 6 to 20 cubs.

The babies, while in the mother's body, already have a long snout, but it is soft, and its teeth are located under the skin. In newborns, the teeth of the “saw” are very small and reach their final length after birth.

Sawfish and man

There has been a commercial sawfish fishery for a long time. The rough meat of these stingrays is edible. But the fins, which are used to make soup, are of particular value. Liver fat is in demand traditional medicine. Of particular value is the unique rostrum, the cost of which reaches or exceeds $1,000.

The reason for the vulnerability of sawfishes is their formidable weapon– a jagged “saw” that often becomes entangled in debris floating in the water or in fishing nets. Poaching causes great damage to the numbers of all species of this group of stingrays. One of them (the Asian sawfish) due to overfishing and worsening environmental situation in the waters of the world's oceans the International Union for Conservation of Nature has assigned the status "Endangered".

And in 2007, a ban was announced on the trade in body parts of all saw-tailed rays: these are fins, “saws” and their teeth, skin, meat and organs.

The sawfish is very similar to a shark, but it would be more correct to classify it as a family of sawfish rays that live in the tropical coastal waters of the Atlantic and Indo-Pacific regions. This stingray is easily recognized by the long bony outgrowth on its snout with many small jagged edges. A real saw. But why does he need it? What is he sawing her in his underwater world?

You will learn about this a little later. In addition to the waters of the three main oceans: Atlantic, Pacific and Indian, these stingrays can be found in coastal areas Mediterranean Sea, as well as off the coast of the American continent during the migration season. The sawfish thrives not only in sea water, but also in brackish and even fresh water, so it can often be seen in river mouths. Sometimes stingrays can be found at such a shallow depth that their large dorsal fins are visible above the surface of the water, cutting through the water surface.

The sawfish has a very impressive size, but up to a gigantic freshwater stingray she still has a long way to go. Average length her body is 4.5-4.8 meters. There are also larger individuals, 6-7 meters. It also weighs a lot - this is how a stingray 4.2 meters long was caught, the weight of which reached 315 kilograms. The heavyweight record belongs to a stingray weighing 2.4 tons. It's a pity that its length is not indicated anywhere.

These rays are born with a long but soft snout with small teeth hidden under a leathery shell so as not to damage the mother. In adult individuals, the length of the “saw” can reach 110-120 centimeters.

"Saw"

Unlike other species of stingrays, the sawfish does not have a spine on its caudal fin. Some people confuse these stingrays with sawnose sharks, which they closely resemble. How can you tell them apart? Everything is very simple. In sharks, the gills are located at the edges of the head, while in stingrays they are located at the bottom. In addition, the latter have a flattened body, the edges pectoral fins fused to the head at the level of the mouth. All these features, as well as the absence of antennae on the snout, distinguish saw-nosed rays from saw-nosed sharks (Pristiophoridae).

Now we come to the answer to the question - why does a fish need a saw? It turns out that with its help, the stingray digs out small fish hidden from it from the silt and sand. In addition to the fact that the saw serves as a kind of “shovel” for him, it is also a formidable weapon. Having burst into a school of fish, the stingray furiously begins to swing the “saw” from side to side. After this, it calmly sinks to the bottom and swallows the wounded or “sawed” fish. This fish is completely safe for humans.

These fish are ovoviviparous, i.e. the female gives birth to already formed cubs, which are located in a leathery shell - the egg. A female can bring 15-20 cubs at a time.

As sad as it sounds, the sawfish is endangered and is listed in the International Red Book.

The "face" of a sawfish

This inhabitant of the World Ocean stands out among others in that it has a jagged bone growth on its head, which really resembles a saw and makes up approximately a quarter of the total body length.

The exact biological name of this fish is the common sawfish, and it belongs to the stingray family. The sawfish (lat. Pristidae) has two fins on its back and one on its tail, and unlike many other stingrays, it does not have a spine.

Just like sharks, the skin of sawfish is covered with placoid scales. Due to their great external similarity, sawnose rays are sometimes confused with sawnose sharks, but they are a completely different family of fish.

They can be distinguished by the way their gills are located: sawfish, like all rays, have gill slits at the bottom of the head, and sawnose sharks have gill slits on the sides. In addition, sawfish are significantly larger in size than sawnose sharks.

Ichthyologists are of the opinion that the length of the sawfish reaches almost five meters, although there is unconfirmed documented evidence that fishermen caught specimens about six meters in length.

This species of fish is listed in the International Red Book and lives in the coastal part of the Atlantic, Indian and Pacific Oceans, as well as in the Mediterranean Sea. Sawfish, which live off the coast of the American continent, migrate from south to north in the summer, and from north to south in the fall.

The common sawfly does not lay eggs, but reproduces by ovoviviparity. One female Sawfish can give birth to fifteen to twenty babies at a time. Moreover, while they are still in the womb, their “saw” is completely covered with skin.

It is almost impossible to find sawfish in the open ocean. For its habitat, it has chosen coastal areas, and sometimes it enters the shallows, and then you can see the dorsal fins sticking out of the water.

It also happens that it enters large rivers that flow into the ocean, and some of the sawfish species, for example, the Australian sawfish, have become so accustomed to fresh water that they live permanently in the rivers of the Green Continent.

The diet of sawfish consists mainly of a variety of small animals that live in the sand and silt covering the bottom. It is for this, and not for any carpentry work, that a sawmill needs a saw. With its help, this type of stingray loosens the bottom soil and digs out those unfortunates from it, who then go into food.

However, there is also evidence that the saw blade can be used by the sawmill not only as a shovel, but also as a kind of saber. Eat numerous testimonies how these bottom fish quickly burst into schools of sardines or mullet and how real fencers hit their prey with a saw, which they calmly ate after it sank to the bottom.

The sawfish became so famous due to its unusual appearance. Previously, there was even a legend that she was capable of sawing a wooden ship, and that is why even experienced people were afraid of meeting her.” sea wolves" However, in fact, this fish is not at all dangerous for humans, and, like most other species of stingrays, when it encounters it, it often tries to quickly hide.

As for its commercial value, it is very small, since the meat of the common sawfly is quite coarse, although quite edible.

Well, the final photo :)

And now a video of how this guy uses his saw interesting fish while hunting.

The scientific name of this creature is the common sawfly. The sawfish belongs to the family of cartilaginous fish (like the shark) and to the superorder of stingrays. This creature received its name and wide popularity due to its appearance. The sawfish has an elongated body, strikingly similar to a shark, but perhaps the most striking external sign What distinguishes it from other fish and rays is the so-called “saw” - a long and flat outgrowth of the snout, on the sides of which there are sharp teeth of the same size. It is curious that this “saw” is almost a quarter of the body length of the entire fish! The sawfish's skin has various shades of gray-olive color, and its belly is almost white.

The sawfish's shark-like body has 2 fins on each side and 2 triangular-shaped dorsal fins. In some species of saw-tailed rays, the tail part smoothly passes into the body, merging with it, but there are also species in which the tail and body are divided into two sections by the caudal fin. It is curious that the similarity of these fish with sharks does not end only with the shape of their body: sawfish, like sharks, have skin covered with placoid scales. Currently, only 7 species of saw-tailed rays are known: green, Atlantic, European, smalltooth, Australian, Asian and combed.

Where does the sawfish live?

The sawfish feels comfortable in both fresh and salt waters, and lives in all oceans except the Arctic Ocean. Favorite place saw-throated rays – coastal waters. This creature is difficult to find in open oceans. Sawfish love to bask in shallow water. It is curious that 5 of the 7 currently known species of sawfish live off the coast of Australia. Australian species In general, sawfish have long been accustomed to fresh water bodies, without swimming into the ocean. The only place where sawfly rays cannot live is in polluted various garbage and water waste.

Sawfish and sawnose shark are not the same thing!

Saw-nose rays are often confused with saw-nose sharks. These are not the same fish! Of course, sharks are the closest relatives of rays, since they belong to the same family of cartilaginous fish, but these are two different types underwater animals. The sawnose shark's snout is elongated and flattened, similar to a sword, and studded with large teeth. This creature lives in warm waters Indian and Pacific oceans. Sawfish are bottom-dwelling and slow-moving fish that feed small fish and small bottom animals.

Sawfish are considered larger fish than sawfish. A case is described in which a sawfish weighing 2400 kg and 6 m long was caught! For comparison: sawwhiskers rarely grow to 1.5 m in length. Sawfish, like their “comrades” the sawfish, feed on small animals living in the ground. They dig them out of the mud with their "saw", using it both as a shovel and as a rake. Often the sawfish wields its nose like a saber or sword, bursting into a school of small mullet or sardines, and then swallows the “defeated” enemies.

Sawfish is an ovoviviparous fish

Sawfish belong to ovoviviparous fish: their young are born as fully formed fish, but located in the shell of a leathery egg. Zoologists who observed saw-throated rays found that their females can give birth to up to 20 young at a time! The “saw” of these fry is formed in the womb, but their stigma is still very soft, and the teeth are completely hidden by the skin and harden only with time. By the way, in the same way