Sawfish lifestyle, differences between sawfish and sawfish sharks. Sawfish (lat. Pristidae). Photo and video of sawfish

The sawfish is very similar to the shark, but it would be more correct to classify it as a family of sawfish that live in the tropical coastal waters of the Atlantic and Indo-Pacific regions. This stingray is easily recognizable by a long bony outgrowth on its muzzle with many small serrations along the edges. Real saw. But what is she to him? What is he sawing for her in his underwater world?

You will learn about this a little later. In addition to the waters of the three main oceans: the Atlantic, Pacific and Indian, these rays can be found in the coastal zones of the Mediterranean Sea, as well as off the coast of the American continent during the migration season. Sawfish feel great not only in the sea, but also in brackish and even fresh water, so it can often be seen in the mouths of rivers. 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 it is still far from a giant freshwater stingray. The average length of her body is 4.5-4.8 meters. There are individuals and more, 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 is a pity that its length is not indicated anywhere.

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

Unlike other stingray species, the sawfish lacks a spike on its caudal fin. Some people confuse these rays with sawnose sharks, which they closely resemble. How to distinguish them? Everything is very simple. In sharks, the gills are located along the edges of the head, in stingrays, they are located below. In addition, in the latter, the body is flattened, the edges of the pectoral fins are fused with the head at the level of the mouth. All these features, as well as the absence of antennae on the snout, distinguish sawn rays from saw sharks (Pristiophoridae).

Now we have come to the answer to the question - why does the fish need a saw? It turns out that with its help, the stingray digs out small fish hiding from it from the silt and sand. In addition to the fact that the saw serves him as a kind of "shovel", it is also a formidable weapon. Having burst into a flock of fish, the stingray violently begins to swing the "saw" from side to side. After that, he calmly sinks to the bottom and swallows the wounded or "sawn" fish. For humans, this fish is completely safe.

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

No matter how sad it sounds, but the sawfish is endangered and listed in the International Red Book.

This inhabitant of the oceans stands out among others in that on his head he has a bone outgrowth with notches, 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. On the back of a sawfish (lat. Pristidae) there are two fins, and one on the tail, and unlike many other rays, it does not have a spike.

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

They can be distinguished by the way the gills are located: in sawfish, like all rays, gill slits are located at the bottom of the head, and in sawnose sharks, on its sides. Besides, saw fish in size significantly exceeds sawnose sharks.

This species of fish is listed in the international Red Book and lives in the coastal parts 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 summer, and from north to south in autumn.

The common sawmill does not lay eggs, but reproduces by ovoviviparity. One female Sawfish is capable of producing fifteen to twenty cubs at a time. At the same time, while they are still in the womb, their “saw” is completely covered with skin.

In the open ocean, it is almost impossible to meet saw fish. She chose coastal areas for her habitat, and sometimes she enters shallows, and then one can observe dorsal fins sticking out of the water.

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

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 the sawmill needs a saw. With its help, this type of stingray loosens the bottom soil and digs out those unfortunate ones from it, which then go to food.

However, there is also evidence that the saw can be used by the sawmill not only as a shovel, but also as a kind of saber. There is numerous evidence of how these bottom fish quickly burst into flocks of sardines or mullets and how real swordsmen hit their prey with a saw, which they calmly ate after it sank to the bottom. The saw fish became so famous due to its unusual appearance. Previously, there was even a legend that she was able to cut a wooden ship, and that is why even experienced "sea wolves" were afraid of meeting with her. However, in reality, this fish is not at all dangerous for humans, and, like most other species of stingrays, when meeting with it, it often tries to hide quickly.

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

The large-toothed sawfish (Pristis perotteti) is now firmly established in the inland waters of its habitat. For example, the population found in Lake Nicaragua appears to be entirely freshwater and may represent a distinct species from the sawfish found in the waters along the coasts of Central America.

Like many sharks, sawfish produce litters of live young. In the body of a pregnant female of this fish, caught off the coast of Sri Lanka, there were 23 fry. To make the process of pregnancy and childbirth not so painful, the teeth of the fry are covered with a protective shell, and the stigmas remain soft and flexible until the very birth of the offspring.

The sawfish has a very impressive size, but it is still far from a giant freshwater stingray. The average length of her body is 4.5-4.8 meters. There are individuals and more, 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 is a pity that its length is not indicated anywhere.

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

Unlike other stingray species, the sawfish lacks a spike on its caudal fin. Some people confuse these rays with sawnose sharks, which they closely resemble. How to distinguish them? Everything is very simple. In sharks, the gills are located along the edges of the head, in stingrays, they are located below. In addition, in the latter, the body is flattened, the edges of the pectoral fins are fused with the head at the level of the mouth. All these features, as well as the absence of antennae on the snout, distinguish sawn rays from saw sharks (Pristiophoridae).

Now we have come to the answer to the question - why does the fish need a saw? It turns out that with its help, the stingray digs out small fish hiding from it from the silt and sand. In addition to the fact that the saw serves him as a kind of "shovel", it is also a formidable weapon. Having burst into a flock of fish, the stingray violently begins to swing the "saw" from side to side. After that, he calmly sinks to the bottom and swallows the wounded or "sawn" fish. For humans, this fish is completely safe.

Off the coast of America, the sawfly makes seasonal migrations: from the southern regions to the northern regions in summer, and in the opposite direction in autumn. It is found not only in sea, but also in brackish and even fresh water. This species sometimes enters rivers, rising high against the current (other species, such as the Australian sawfly - Pristis leichhardti, constantly live in rivers). Sawfish feed mainly on various small animals living in the ground. To dig them out of the mud, sawmills use their saw, which is used in this case as a shovel and rake. Sometimes they observed how they, breaking into a flock of small fish (sardine, mullet), acted like a saber with a saw, hitting their prey, and then swallowing it at the bottom. Sawfish are of little economic importance. Their meat is rather coarse, but quite edible. They pose no danger to humans.

Belongs to the group of cartilaginous fish. This group includes sharks (a typical representative is), stingrays and skates. All cartilaginous fish have a skeleton made of cartilage, as opposed to a bone skeleton like other fish such as snook, red drum or tarpon. The sawfish belongs to the chordate type and belongs to the Pristidae family. The sawfish has a characteristic elongated flat snout similar to a serrated saw, and the body, appearance and swimming style are more reminiscent of a shark. A process similar to a saw makes up approximately 20% of the total body length. After a fish loses some teeth on its snout, they no longer grow back.

General description and characteristics of sawfish

Sawfish around the world are little studied and no one knows for sure the exact number of species of fish in this group. Scientists estimate that seven species of sawfish are currently known to exist around the world: green, Atlantic, European, fine-toothed, Australian, Asian and crested. Two species that exist in the western Atlantic Ocean are the sawfish and the small-toothed sawfish. Both species look very similar but can be distinguished by counting the saw teeth on both sides of the snout. The sawfish usually has 23-34 teeth on each side, while the fine-toothed sawfish has only 17 to 22. Both species are found in Florida, but only 3 small-toothed sawfish have ever been recorded in that state. The typical range of the smalltooth sawfly is further south and west of the United States. Sawfish are by far the most common sightings on both coasts of Florida. Hundreds of specimens of this fish have been recorded throughout Florida, but in the last decade or so, most have been in the southwest of the state.

Where does the sawfish live

Most often, sawfish are found in the western Atlantic from Brazil to Florida, including the Gulf of Mexico. Several species of sawfish are found off the coast of Australia. Sawfish prefer to live in the coastal strip, but cannot exist in waters polluted with garbage and waste. Sometimes they swim so close to the surface of the water that a large dorsal fin is visible. Sawfish are found in both marine and fresh water. Residents of the Florida peninsula can see these fish almost all year round during the warmer months. Sawfish were once common throughout the state's waters, especially in the late 19th and early 20th centuries.

In the late 1800s, a fisherman reported catching about 300 sawfish with his net during one fishing season. Other fishermen have reported seeing "large and small" sawfish along the peninsula's western coast. Despite the lack of published studies, a decline in sawfish populations has been documented. This is believed to be related to commercial fishing activities (nets, trawls, seines) that directly or indirectly contributed to the problem.

Sawfish: meaning for humans

Due to the unusual shape of the body, the sawfish is easily entangled in the nets, and they cause significant damage to it. Sawfish have minimal commercial value. Its meat is rather coarse and is not used for food. Most of the fished specimens either suffocated or were killed. Sport fishing has a lesser impact on the population of these fish in Florida. Sawfish have historically been popular in the curiosity trade.

The mortality of the fish due to overfishing, combined with its limited reproductive capacity, caused a decline in numbers in Florida in the second half of the 20th century. Because of this, sawfish have been banned from trapping in Florida since 1992. On April 1, 2003, the sawfish was declared an endangered species in the United States by the National Marine Fisheries Service. This declaration gives the species federal protection under the Endangered Species Act as of May 1, 2003. A 2.1 meter long specimen was once caught and released back while sport fishing.

What does sawfish eat and how to catch it

The main food of the sawfish is crabs, shrimps and other bottom invertebrates, as well as small fish such as mullet and members of the herring family. The sawfish obtains food by digging up mud with its nose in search of prey. Sometimes she breaks into a school of smaller fish and, waving her nose, rolls them over the teeth before eating.

Sawfish, like other representatives of this group of fish, can be hooked with bait from fresh or frozen fish or shrimp. The sawfish can also use its nose for defense. Therefore, while swimming, she swings it strongly from side to side. Care must be taken when approaching sawfish of any size. Although the sawfish will help protect itself from the threat, the only case of an unprovoked attack on a person was recorded on the southern coast of the Atlantic Ocean by a small fish up to a meter long - it injured a person's leg. Other attacks on people, most of which were almost always provoked, have been recorded in Panama City Bay. There is a fact of unconfirmed attacks off the coast of India.

Reproduction of sawfish

Very little is known about the size, age, maturity, and reproduction of the Florida sawfish. This fish can grow up to 6 meters in length, and the weight of some specimens reaches 300 kilograms. Female and male small-toothed sawfish in Lake Nicaragua reach sexual maturity at a length of approximately 3 meters. Sawfish are ovoviviparous and reproduce by internal fertilization, as do sharks and rays.

Embryos in the uterus grow without a placental connection with the mother and feed on the yolk stored in tissue cells connected to the embryo. The period of bearing offspring of the sawfish is little known, but in the small-toothed sawfish it lasts about 5 months. Young fish are born in late spring and during the summer in South Florida. The female brings 15-20 cubs and they are born in a leathery egg, inside of which there is a fully formed fish.

There was such a case. Up to 20 juveniles died after being washed ashore. The length of each of them ranged from half a meter to eighty centimeters. Before birth, the teeth of the saw are soft and not fully developed so as not to injure the mother. After birth, they quickly reach a proportional size.

Does the sawfish have teeth or spikes on its "nose"?

In fact, saw teeth are not teeth at all, but rather modified spikes. They are covered with scales. The reproductive cycle of the sawfish is unknown, but the small-toothed sawfish produces offspring every second year of life. Both species grow very slowly and reach maturity by 10 years, and can live up to 30 years or more. Sawfish in Florida are most commonly found in estuaries and bays. They used to be numerous, but now they are rare. Sawfish are found in a wide range of habitats including algae, mud bottoms, sandy bottoms, artificial reefs, mangrove shorelines, bridges and piers. They can also be found several kilometers from rivers in low salinity conditions. Large individuals can be found in estuaries and lagoons, artificial reefs or sunken ships.

Some marine inhabitants got their names due to their external resemblance to some objects, things or tools. For example, a saw fish: 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.

Such an unusual “detail” on the front of the head has two groups of cartilaginous fish - sharks and rays. But the name "saw" was assigned specifically to sawfly rays, and the proposed article contains information only about these fish. About sawnose sharks and a detailed description of how to distinguish them from sawnose rays.

Detachment sawtoothed

Among the cartilaginous fishes there are two superorders, one of which is. Groups are distinguished in it - detachments. The sawtooth detachment is very original due to the 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 Sawfish (Pristidae), known as sawfish. Here there is only a single genus, including seven species.

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

Appearance Features

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

• the body is the same elongated;
• the tail is practically not separated from the body and is its continuation;
• there are two large high dorsal fins;
• in some species, the caudal fin has two lobes;
• the skin is covered by placoid scales.

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

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

The pectoral fins are broad and wing-like. They have grown together with the head and play an important role in swimming (swinging). There is no anal fin. The dorsal side of the body is dark in color, and the ventral side is light. Sawfish are large fish and can reach over 7 meters in length (European sawfish), while 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 sawfly stingray uses its unusual tool for two purposes:

• discover potential prey;
• and catch her (stun and immobilize).

A feature of the structure of the “saw” (scientifically it is called “rostrum”) is the deep and strong fixation of its teeth in the cartilaginous tissue of the rostrum. If any of the teeth breaks or is damaged, then it will never grow again. Sawfish rays of different types have from 14 to 34 pairs of teeth. They all have the same size.

All sawfly stingrays are divided into two conditional groups: one has large “saw” teeth, and the second group has small teeth. The mouth and sawfly also have teeth, 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 a modified placoid scale found only in cartilaginous fish (in structure, such scales really look a bit like 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 from side to side with this cutting and piercing tool, the sawfish successfully defends itself.

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

Electroreception and prey search

We continue to get acquainted with the formidable "weapon" of the sawn ray - its elongated rostrum-saw. Numerous electroreceptors are located on the surface of the "saw", which help to find food objects in muddy water, just as they do. Ampullae of Lorenzini (organs that capture electric fields from animals) are found in large numbers on the upper surface of the rostrum. This enables the sawfish to receive information about living objects that float in higher layers of water above it and often become its prey.

Sawfish stingrays feed on small fish and various invertebrates living in the ground.

With their flat saws, sawfish dig the ground for the extraction of burrowing invertebrates, most often mollusks and crustaceans. Sometimes they use a saw as a saber. Bursting into a cluster of medium-sized fish (mullets or sardines), the stingray brandishes its weapon and hits the prey, which falls to the bottom. Descending after the affected victims, the sawfly swallows them.

Lifestyle and biology features

The predominant habitat of sawfish is shallow water. The depth is sometimes so small that both high dorsal fins of a stingray lying near the bottom stick out above the surface of the water. Off the American coast, the sawfish is a migratory species and makes massive seasonal movements: in the summer from southern to northern waters, and in the fall they return again to the south.

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

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

sawmill and man

For a long time, commercial fishing for sawfish has been carried out. The coarse meat of these rays is edible. But the fins, which are used to make soup, are of particular value. Liver fat is in demand in traditional medicine. Of particular value is the unique rostrum, the cost of which reaches and exceeds $1,000.

The reason for the vulnerability of sawfish is their formidable weapon - a serrated "saw", which often gets entangled in the accumulation of debris floating in the water or in fishing nets. Great damage to the population of all species of this group of stingrays is caused by poaching. One of them (Asian sawfish), due to overfishing and the deteriorating environmental situation in the waters of the world's oceans, has been assigned the status of "Endangered" by the International Union for Conservation of Nature.

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