home Pregnancy and children Is piranha dangerous in an aquarium? The largest piranha in the world is Lee the piranha.

Is piranha dangerous in an aquarium? The largest piranha in the world is Lee the piranha.

If you conducted a survey about which fish is the most dangerous on Earth, piranha would definitely be among the top three. Despite quite small sizes the fish itself, a school of piranhas in a matter of minutes will leave only a skeleton of a person who has fallen into the water. At least, this is what happens in numerous horror films and horror books. But is this really so?

The compressive force of the jaw muscles relative to body size is the highest in piranhas compared to any other vertebrate in the world.

First you need to understand whether the piranha is really an extremely aggressive creature that attacks everything that moves in the water. This may sound unexpected, but piranha is a very cautious fish and does not pose any danger to humans. Exists a large number of evidence of a person swimming in piranha-infested water without any harm to his health. This was fully demonstrated by Herbert Axeldorf, a famous biologist specializing in the study tropical fish. To prove the safety of piranhas for humans, Herbert filled a small pool with piranhas and dived into it, leaving only his swimming trunks on. After swimming for some time among the predatory fish and without receiving any harm to his health, Herbert took fresh blood-soaked meat in his hand and continued to swim with it. But several dozen piranhas in the pool still did not approach the person, although quite recently they happily ate the same meat when there was no one in the pool.

Piranhas, considered fearsome predators with an insatiable thirst for fresh flesh, are actually rather timid fish that do not dare to approach large creatures.

It is known that piranhas prefer to stay in large schools, and if one piranha is seen in the water, there are always others nearby. But piranhas do this not because it is easier for a school of predatory fish to overwhelm and kill a person who enters the water, but because piranhas themselves are a link in the food chain for other larger species of fish. Being in a flock of dozens of individuals, the chance that you will be eaten is quite low.

Moreover, experiments with piranhas have shown that when alone, these fish do not feel as calm as if they were surrounded by other fish.

But despite their peaceful behavior towards humans, piranhas are real killing machines for other fish species that are lower than them in the food chain. Their powerful jaws are designed to bite and tear, and their dense, muscular bodies are capable of incredibly fast movements and jerks underwater. The piranha's jaw muscle contraction force relative to body size is believed to be the highest of any other vertebrate in the world. For example, the common piranha can easily bite off the finger of an adult.

But in history there has not been a single reliable case of a fatal attack by piranhas on a person. But this does not mean at all that these fish never bite a person or an animal that enters the water. And this behavior is almost always caused not by the aggressive behavior of the fish, but by self-defense or abnormal weather conditions, because of which the behavior of piranhas begins to differ sharply from usual. Abnormal weather conditions mean a period of drought, when the rivers in which piranhas live dry up, and many fish remain in depressions filled with water, but cut off from the main channel, deprived of food. Starving predators gradually begin to eat themselves and may well rush at any creature that comes close to the water. Sometimes the tendency of piranhas to behave aggressively is recorded during the spawning period, when they rush at a person or animal in self-defense, but such cases are extremely rare. And of course there is no talk of a collective attack by piranhas on humans.

But all of the above does not mean that piranhas will refuse to eat human flesh. Unfortunately, sometimes tragic incidents occur on the water - people or animals drown. An already lifeless body floating in the water attracts many fish, including piranhas, which leave specific bites on it. People who see this think that the cause of death was an attack by piranhas - this is how most myths about attacks by flocks of piranhas on people or animals are born.

This is interesting: Suppose, in some unknown way, a huge school of piranhas of 400-500 individuals was driven crazy, and now they attack everyone who is in the water. For example, if this unfortunate person turns out to be an adult, then 500 piranhas will be able to gnaw him to the bone in 5 minutes!

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From films and fiction books, we know that if you put your hand in the water where piranhas live, they will gnaw it off in a minute. Well, okay, maybe this is not accurate, but if there is some kind of wound on the body and blood gets into the water, then the piranhas can smell it a kilometer away and will definitely attack a person with the whole flock and certainly only a skeleton will be left of him.
Is this really true?

This was fully demonstrated by Herbert Axeldorf, a famous biologist specializing in the study of tropical fish. To prove the safety of piranhas for humans, Herbert filled a small pool with piranhas and dived into it, leaving only his swimming trunks on. After swimming for some time among the predatory fish and without receiving any harm to his health, Herbert took fresh blood-soaked meat in his hand and continued to swim with it. But several dozen piranhas in the pool still did not approach the person, although quite recently they happily ate the same meat when there was no one in the pool.

Piranhas, considered fearsome predators with an insatiable hunger for fresh flesh, are actually rather timid fish and scavengers that do not dare to approach large creatures.

Moreover, experiments with piranhas have shown that when alone, these fish do not feel as calm as if they were surrounded by other fish.

But in history there has not been a single reliable case of a fatal attack by piranhas on a person. But this does not mean at all that these fish never bite a person or an animal that enters the water. And this behavior is almost always caused not by the aggressive behavior of the fish, but by self-defense or abnormal weather conditions, because of which the behavior of the piranhas begins to differ sharply from usual. Abnormal weather conditions mean a period of drought, when the rivers in which piranhas live dry up, and many fish remain in depressions filled with water, but cut off from the main channel, deprived of food. Starving predators gradually begin to eat themselves and may well rush at any creature that comes close to the water. Sometimes the tendency of piranhas to behave aggressively is recorded during the spawning period, when they rush at a person or animal in self-defense, but such cases are extremely rare. And of course there is no talk of a collective attack by piranhas on humans.

Surprisingly, piranhas, being, according to many, one of the most the most dangerous predators, at the same time unusually timid! It is advisable to keep the aquarium in which piranhas live away from sources of noise and shadows, otherwise your pets will constantly be on the verge of fainting! It is a well-known fact among aquarists that a click on the glass or a sudden movement near the aquarium is enough for piranhas to faint. They also often faint during transportation from the place of purchase to their future home.

Piranhas are monsters from horror films and scary stories, small but bloodthirsty inhabitants of the waters of the Amazon and other rivers in the territory South America(Colombia, Venezuela, Paraguay, Brazil, Argentina). What do we know about them? Probably nothing. After all, all knowledge is limited to just one species - the ordinary piranha, which has gained notoriety.

The Piranha family includes slightly more than 60 species of fish. And, oddly enough, most of them are herbivores; they practically do not eat animal food. The size of piranhas depends on the species, carnivores generally reach 30 cm, and their vegetarian relatives can gain significant weight and grow more than one meter in length. The color also depends on the species, but is mainly silver-gray, becoming darker with age. The body shape is diamond-shaped and tall, laterally compressed. The main food for predators is a variety of piranhas that can also feed on animals or even birds that they meet along the way. For herbivorous species, the Amazon and its tributaries abound in various vegetation; these fish do not disdain nuts and seeds that fall into the water.

Jaw structure

It is typical for piranhas amazing structure jaw apparatus, perhaps, which has no analogues in nature. Everything is provided in it down to the finest detail. The teeth, triangular in shape and measuring 4-5 mm, are lamellar and sharp, like a razor blade, slightly curved inward. This allows them to easily cut through the flesh of the victim, tearing off pieces of meat. In addition, the upper and lower teeth fit perfectly into the sinuses when the jaw is closed, creating a strong pressure. This feature allows piranhas to bite through bones. When closed, the jaws close like a trap. According to the latest research by scientists, the bite force is 320 newtons and has no analogues in the animal world. When a piranha's jaws bite, it exerts about 30 times its weight in pressure.

Where do piranhas live?

These are inhabitants of freshwater bodies of water in South America. The Amazon basin contains a fifth of all fresh water; this river is full of a variety of fish. Piranhas live along the entire length of the river and are the subject of many legends and stories of local residents. occupies vast territories, most of which belongs to Brazil, but also to Ecuador, Colombia, Bolivia and Peru. Piranhas also feel great in other rivers; their habitat area on the South American continent is very large.

IN Lately This fish has become very popular in home keeping and breeding. A piranha in an aquarium will grow smaller than its typical size in natural conditions, and loses a little of its aggressiveness. Surprisingly, with such a threatening appearance, they become timid in confined spaces and often hide in artificial shelters.

All piranha fish are combined into one family and are divided, according to zoological classification, into three subfamilies.

Myelin subfamily

Myelins are the most large group, it unites seven genera and 32 species. These are herbivores and absolutely harmless piranhas (photo). Fish eat plant foods. The color is quite varied, depending on the species. The body shape is characteristic, laterally compressed and tall. Juveniles are steel-silver in color, with varying degrees of spotting, which darkens to a chocolate gray color as they grow. Sizes vary from 10 to 20 centimeters. Many representatives of this subfamily are bred in aquariums. They need a large volume of water and sufficient hiding space, as they are quite shy fish. Aquarium piranha from the myelin subfamily will feel good at a water temperature of 23-28 degrees, and the daily diet should include lettuce, cabbage, spinach, peas and other vegetables. Some species even feed on nuts in natural conditions, easily cracking the strong shell with their powerful jaws.

Black pacu is the brightest representative of myelin

The black pacu (or Amazon broadbodied) is the most famous representative Myelin subfamily. In addition, it is also the largest: its dimensions range from 30 centimeters to one meter or more, although it is not a predator. The color of adult individuals is quite modest, brownish-brown, but the young are silver in color with a large number of spots throughout the body and bright fins. Black pacu meat has good taste qualities and is used by local residents. These are commercial piranhas. Aquarium conditions are also quite suitable for them, but the size of the fish will be somewhat smaller than in nature, on average about 30 centimeters, life expectancy - within 10 years or a little more. Keeping this species requires a large aquarium (from 200 liters) and good care.

Subfamily Catoprionines

This fish, similar to the common piranha and being its closest relative, mainly has plant foods (60%) in its diet, and only 40% consists of small fish. But it still needs to be kept separately from other fish, otherwise very small ones will be eaten, and large ones risk being left with damaged fins and partially without scales. As animal food, you can use small shrimp or fish, earthworms, and plant food - spinach leaves, lettuce, nettles and other greens.

Subfamily Serrasalmina

These are the same ruthless predators; the subfamily is represented by only one genus and 25 species. They all eat animal food: fish, animals, birds. The size of piranhas of the Serrasalmina subfamily can reach up to 80 cm in size, reaching a weight of up to 1 kg. This is a real threat to animals (not to mention fish), which can be several times larger in size, but this does not stop the piranha. The appearance of small predators is truly menacing: it protrudes significantly forward and is slightly curved upward, the eyes are bulging, and the body is characterized by a rounded flat shape. In reservoirs they prefer to stay in schools, but when attacking a prey they act independently of each other, so it cannot be said that these are close-knit group fish. Piranhas react to movement in the water, this attracts their attention. When one of them finds a victim, the others immediately flock to the spot. Moreover, there is an opinion among zoologists that piranhas are capable of making sounds, thereby transmitting information to each other. A flock of piranhas can leave an animal with only bones in a few minutes.

The information that they are able to sense blood at a considerable distance from the victim is true. Piranha fish live in troubled waters Amazons, and it is natural that they had to adapt to conditions of poor visibility, as a result - a well-developed sense of smell. Piranhas are indeed attracted to blood, this is a signal that a prey has arrived.

In addition, they do not disdain carrion and even their sick or weakened brothers. Only a few species pose a real danger to animals and humans.

Common piranha

The most famous representative, around which conversations do not subside, is the Common Piranha. The length of individuals of this species can reach up to 30 centimeters, but they are generally the size of a human palm. Common piranhas (photo of the fish below) have a greenish-silver color with many dark spots throughout the body; the scales on the abdomen have a characteristic pinkish tint. They live in flocks of approximately one hundred individuals.

In recent years, ordinary piranhas have also been very popular in home keeping. Aquarium conditions help reduce aggressiveness. But you still need a separate aquarium.

Black piranha

This is another species from the Serrasalmina subfamily, very common in nature and popular in home breeding. Habitat - and Orinoco. The body shape is diamond-shaped, and the color is dark, black and silver. In young fish, the abdomen has a yellow tint. The black piranha is an omnivorous predator; everything is suitable for its diet: fish, arthropods, birds or animals that accidentally fell into the water. Such indiscriminate eating led to their fairly high numbers in the waters of the Amazon. Although in terms of aggressiveness the species is inferior to the same ordinary piranha. An aquarium for such fish requires a large one, more than 300 liters. The difficulty of breeding lies in the aggressiveness of piranhas towards each other. Reproduction is possible if aquarium members of the family eat properly; if there is an abundance of animal food, they become obese, which can become a significant obstacle to the appearance of offspring. The photo shows a black piranha.

Myth one: piranhas attack humans

It is difficult to judge this clearly, since the data is very contradictory. Many scientists and zoologists who spent more than one year in the Amazon have never witnessed an attack; in addition, they themselves, exposing themselves to danger for the sake of experiment, swam in the muddy waters of the river, where a few minutes before they had caught piranhas, but there were no attacks followed.

For a long time, there was a story about a bus with local residents that drove into one of the tributaries of the Amazon, and all the passengers were in literally words are eaten by piranhas. The story really took place in the 70s of the last century, 39 passengers died, but one managed to escape. According to eyewitnesses, the bodies of the victims were indeed badly damaged by piranhas. But it is not possible to judge whether this was an attack and whether it was the cause of death.

There are reliable sources of bites on the beaches of Argentina when the fish were the first to attack. But these were isolated cases. Zoologists explain this by the fact that piranhas, whose spawning just begins at the height of beach season, build nests in shallow water. Therefore, this behavior of fish is quite natural: they protected their offspring.

In addition, piranhas are most dangerous for humans and animals during drought periods, when the water level in rivers reaches its minimum, which affects their diet: there is less food. Local residents know about this and do not enter the river at this time. The safest season is the rainy season, when the rivers overflow.

Myth two: piranhas attack in packs

There are many stories about terrible attacks by an entire pack, all of which are fueled by numerous feature films. In fact, large individuals do not prowl in search of prey in the river; they stand in one place, usually in shallow water. The fish waits for its prey, and as soon as this prey appears, the piranha heads to the right place. Attracted by the noise and smell of blood, others rush there. Piranhas gather in schools not to hunt prey, but to defend themselves from the enemy - this is what many scientists believe. It would seem, who could harm them? However, even such a predatory fish has enemies. Piranha, gathering in schools, defends itself from river dolphins that feed on them, and for people they are harmless and quite friendly. In addition, among natural enemies piranhas - arapaima and caimans. The first one is giant fish, which is considered practically a living fossil. Possessing amazing, super-strong scales, it poses a real threat to piranhas. Fish found alone instantly become victims of arapaima. Caimans are small representatives of the Crocodile order. Zoologists have noticed that as soon as the number of these caimans decreases, the number of piranhas in the river immediately increases.

Myth three: piranhas appear in Russian water bodies

Incidents did take place, but this was either the result of the behavior of careless amateurs aquarium fish, or intentional launch into a body of water. In any case, there is no need to worry. Although piranhas adapt perfectly to any conditions, the main factor for their successful existence remains the same - a warm climate and water (within 24-27 degrees), which is impossible in our country.

Of course, these Piranhas are dangerous and very voracious, but still the stories about them are often overly embellished and far-fetched. The indigenous population of South America learned to coexist next to piranhas and even made them a commercial target. Nature has not created anything useless: if wolves are what they are, then piranhas perform a similar function in water bodies.

Popular films frighten audiences with the image of a bloody school of fish, bringing death and devouring people not even in dozens, but in hundreds. Meanwhile, there is not a single fact of human death from the teeth of piranhas! Yes, there were bites. Most often, when curious people stuck their fingers into the aquarium. But to dub the unfortunate fish cannibals is already too much.

Many scientists who have been living on the shores of the Amazon for decades and studying its flora and fauna confirm that during their entire stay they have never seen a person seriously injured by piranhas.

Piranhas attack in a flock.Piranhas attack only in packs, no, this is not so, in fact, the same scientists have proven that piranhas organize groups solely for the purpose of protection!

These small fish often suffer from attacks from large predators, so instinct forced them to unite with their brothers in order to fight back and survive.

Piranhas are crazy about fresh blood, and hunt any creature that carelessly ends up in the river

Yes, the smell of blood makes these fish excited. As, indeed, any predator in wildlife. Try waving your bloody hand in front of a lion's nose - the animal is unlikely to remain unperturbed. Even peaceful cows become violent at the sight and smell of blood. However, this trait is commonly attributed to piranhas. About attacks on people and cattle other story.

Expert opinion

By their nature, piranhas are orderlies who perform a noble function and rid the waters of the Amazon of carrion. These eat fish dead and dying animals, and never attack anyone who can fight back.

In hungry years, there were cases when piranhas, out of desperation, could even hunt sleeping crocodiles and their own relatives. But what wild animal, especially a predator, would act differently?

Where did the legend come from?

Do piranhas eat people? Of course not, this is another myth invented by man. The culprit behind the piranha's creepy reputation was Theodore Roosevelt. When the president was traveling through the Amazon, the locals decided to shock him with a brutal performance. They collected hundreds of piranhas and kept them without food for several days, and then, in the presence of Roosevelt, they drove a cow into the water with the fish, mad with hunger. Naturally, almost nothing remained of that one in a matter of minutes. And the president told the whole world about the bloodthirstiness of “these creatures.” People carried out a cruel experiment for their own amusement, and managed to blame it on innocent creatures. That’s the whole “terrible” secret of piranhas.

27.04.2018
Over the past few years, from Russian seas, rivers and lakes, amazed fishermen pulled out not only tropical buffalo fish or no less exotic parrot fish, but more dangerous catches were caught in the net, such as barracuda, puffer fish and piranhas. Where did they come from in the Russian expanses?

Nadezhda Popova

The editor of Novye Izvestia reported about the amazing catch in the Tver province and Chief Editor newspaper "Voice of Udomlya", former mayor of the nuclear town Dmitry Podushkov. “In the cooling lake of our Kalininskaya nuclear power plant avid fisherman Igor Slivka caught a pacu fish - a type of piranha. We still can’t understand how the pacu ended up with us, in the Tver province?”

Indeed, a mystery!

But the real piranha was caught in Lake Ivan by experienced fisherman Ksenia Demina from the Trans-Baikal village of Tasei. There was no limit to surprise... Ksenia Demina sent a “portrait” of an outlandish fish to scientists at the Institute natural resources, ecology and cryology, Siberian Branch of the Russian Academy of Sciences. Ichthyologist, senior Researcher Institute Evgenia Gorlachev concluded: this is, indeed, a piranha.

In Russia, piranhas have been caught in fishermen's nets for several years now. There is a known case when experienced fisherman Andrei Malyshev caught a piranha weighing more than 2 kg on Lake Sredny Kaban in Tatarstan. Piranha caught earthworm. But the fisherman with 40 years of experience was afraid to fry it. Malyshev took the catch to ichthyologists. Associate Professor, Department of Bioecology, Kazan University federal university, ichthyologist Rustem Saifullin confirmed that the caught fish was a piranha. But where did it come from in Lake Sredny Kaban? Go ahead. A resident of the Rostov region, Grigory Kurilkin, suffered from a piranha attack. While fishing in the Solenenky pit, he was attacked by a predator with sharp teeth when he went knee-deep into the water and cast his fishing rod. The fish grabbed Kurilkin's leg, tearing off a piece of meat. The wound turned out to be very deep, the piranha bit through the leg to the bone. These creepy little fish with razor-sharp teeth have already been pulled out of the Volga, Ob, Irtysh and Ishim. Two large piranhas were caught by amateur fishermen in the Belovo Reservoir in Kemerovo region. And there are more and more reports of unauthorized penetrations of bloodthirsty piranha into peaceful Russian water bodies. But the homeland of this fish is South America. Where did the piranha come from in Lake Ivan? And in Lake Sredny Kaban? Piranhas can gnaw the carcass of a large animal down to the skeleton in one minute. In 1981, in Obidus (Brazil), piranhas instantly tore to pieces 300 people: they found themselves in the water due to a shipwreck.

But not only piranhas began to climb into fishermen’s nets. Others, no less outlandish and very dangerous fish continue to float up in rivers and lakes of Russia. In the lower reaches of the Ob, fishermen almost caught a group of electric eels. This miracle of nature has strong electrical charges and produces a discharge of 600-800 volts. But this electric fish lives in the rivers of Brazil and Colombia. How did electric eels get to the lower reaches of the Ob?

Near the Southern Kuril Islands, fishermen discovered an exotic half-meter sea snake living in subtropical waters. A tsutsik goby from the Sea of Marmara suddenly showed up in the cold Gulf of Finland. Crimea has its own surprises. Over the past few years, 25 new species have been discovered in the Black Sea sector of Crimea sea fish. Not long ago, in the bay of Sevastopol, fishermen caught a terrible ball fish with huge needles. The copy was delivered to scientists. The monster turned out to be a poisonous fugu fish that lives off the coast of Japan. Senior Researcher, Institute of Biology south seas Alexander Boltachev believes that the appearance of the puffer fish, or pufferfish as it is also called, in the Sevastopol Bay is a mystery.

But she may have a clue.

“Such “aliens” usually end up in bodies of water containing ballast water from ships,” says Alexander Boltachev. – Sailors need ballast to increase the stability of ships at sea.

In the old days, stones, sand or cast iron could serve as ballast. But on modern ships, seawater serves as ballast. Huge tanks with a capacity of millions of liters are filled with a mixture of water and everything that the pumps have drawn in. It could be algae, silt, and yes - various Marine life. However, there is a procedure that should prevent the transfer of fauna: ballast water must be discharged at the entrance to the sea.

“But not every ship does this in good faith,” says Yulia Korniychuk, scientific secretary of the Institute of Biology of the South Seas. – Migration of fauna with ballast waters is very dangerous phenomenon. By the way, Vibrio cholerae was also brought from Asia to Latin America specifically with ballast water.

Recently, blue crab, tropical butterfly fish and Mediterranean barracuda have also fallen into the hands of Sevastopol ichthyologists.

Indeed, exotic fish and all sorts of small things end up in a new habitat with ballast waters, says hydrobiologist Mikhail Belykh. - Today main reason the spread of invaders is human activity. Canals in Russia and Europe began to be built back in the 19th century, connecting isolated rivers and reservoirs. The inhabitants of these reservoirs learned to travel across the seas and oceans. They are easily attached to the bottom of the ship and set sail. Previously, ichthyologists believed that a large number of uninvited guests would not take root in new “homes”: different water composition, different temperature, lack of usual spawning places. But it turned out that this is not so. The newcomers are settling very energetically. For example, on the Volga. In the early 1980s, the level of the Caspian Sea suddenly began to rise. The salinity level of the water has increased. And for many fish such water became suitable for life. And over the past few years, the average annual water temperature in the river has increased by 3 degrees. The former inhabitants of the Volga left to the north. And the inhabitants of the southern reservoirs immediately moved into their places. Otherwise, where did the largemouth buffalo fish come from in the Volga River basin - is it a North American chukuchan fish?

Real headache For nuclear Russia- zebra mussel or zebra mussel. The bivalve mollusk, moving in its larval form in ballast water, demonstrates lightning-fast reproductive growth when the water is released. This zebra pollutes all available hard surfaces, altering the habitat, ecosystem and food chain. And calls serious problems with contamination of hydraulic infrastructure. High economic costs associated with cleaning water intake pipeline systems and sluices have been noted. They especially suffer from zebra mussels in Russia nuclear power plants. In 2015, at the Kalinin nuclear power plant (in the cooling pond of which they caught the pacu fish, which we talked about at the very beginning), a zebra mussel surrounded the water supply system. Losses? Minus 20 million kWh. Almost all Russian nuclear power plants located in the European part of the country, to one degree or another, fall into the risk zone in this regard. The Baltic NPP, in particular, if it is finally included in the network, may also face such a problem in the future!

What else is interesting? Back in 2002, Russia, Iran and India signed an agreement on the creation of the North-South water transport route, which would connect the Baltic Sea with Persian Gulf through the Volga and Caspian Sea. A canal has already been dug through Iran, connecting the Caspian Sea with the Persian Gulf. Over the years, the North-South transport corridor has expanded greatly: now it is a multimodal network of sea (and other) transportation. And it united not only Russia, India, Iran, but also Afghanistan, Armenia and Azerbaijan. Baku joined the project quite recently. Now the corridor will go around the Suez Canal and will allow, for example, fruit to be delivered from Mumbai to St. Petersburg in just 14 days. Today, transportation takes 42 days. Who else will we start catching in our Oka and Dvina, as well as in Lake Ivan? Or rather, what are we already catching? A dog shark, an ocellated knife, a stone fish? Or hairy monkfish, blob fish? God forbid you catch a redfin or a sunfish.

But what to do with uninvited migrants?

It appears that the situation may be improving after all, as the Ballast Water Management Convention came into force a few months ago. This happened in Nagoya (a major port city in Japan) at the Tenth Conference of the UN Convention on Biological Diversity.

And now there is hope that it will not only minimize the risk of invasion of alien species through ballast water, says hydrobiologist Mikhail Belykh, but will also provide an international platform for international shipping, providing clear and reliable standards for the management of ships' ballast water. In accordance with its terms, shipowners must equip ships with systems to remove, neutralize, and prevent the intake or discharge of aquatic and pathogenic organisms in ballast water and sediments.

From the "NI" dossier.

Dog fish - also known as pufferfish, also known as puffer fish, also known as globefish, diodont, fahak, ball fish - is a deadly poisonous creature. Swims tail first. Its caviar, skin, and especially its liver contain tetrodotoxin, a nerve poison. Fugu poison is 25 times stronger than curare. One such “dog” can kill up to 40 people. In Japan, fugu is considered a delicacy. There is no antidote for fugu poisoning.

Piranha - subfamily freshwater fish of the characin family, living in rivers and reservoirs of South America. Large fish, olive-silver with a purple or red tint. Piranhas are capable of making various sounds. And when taken out of the water, they begin to bark or croak. The special structure of the powerful lower jaw and teeth allows the piranha to snatch from its prey large pieces meat.

The electric eel is the most dangerous of all electric fish. In terms of the number of human victims, they are ahead of even piranhas. They can deliver powerful electrical shocks, which can cause heart failure. In areas where electric eels are found, local residents have come up with a simple way to catch these fish. They are caught on... cows! Fishermen noticed that cows very easily endure electric shocks from snake-like fish, so they drive the cattle into a river with eels and wait until the cows stop mooing. The calmness of the herd is a signal that it is time to pull the eels out of the river: for a while they become safe - “de-energized”!

Based on materials from: newizv.ru

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