Tell us about electric fish. How much current do they produce?
Electric catfish.
Electric Stingray.
V. Kumushkin (Petrozavodsk).
Among electric fish, the lead belongs to the electric eel, which lives in the tributaries of the Amazon and other rivers of South America. Adult eels reach two and a half meters. Electrical organs - transformed muscles - are located on the sides of the eel, extending along the spine for 80 percent of the entire length of the fish. This is a kind of battery, the plus of which is in the front of the body, and the minus is in the back. A living battery produces a voltage of about 350, and in the largest individuals - up to 650 volts. With an instantaneous current of up to 1-2 amperes, such a discharge can knock a person off his feet. With the help of electrical discharges, the eel protects itself from enemies and obtains food for itself.
Another fish lives in the rivers of Equatorial Africa - the electric catfish. Its dimensions are smaller - from 60 to 100 cm. Special glands that generate electricity make up about 25 percent of the total weight of the fish. The electric current reaches a voltage of 360 volts. There are known cases of electric shock in people who swam in the river and accidentally stepped on such a catfish. If an electric catfish is caught on a fishing rod, then the angler can also receive a very noticeable electric shock that passes through the wet fishing line and rod to his hand.
However, skillfully directed electrical discharges can be used in medicinal purposes. It is known that the electric catfish occupied a place of honor in the arsenal traditional medicine from the ancient Egyptians.
Electric stingrays are also capable of generating very significant electrical energy. There are more than 30 species. These sedentary bottom dwellers, ranging in size from 15 to 180 cm, are distributed mainly in the coastal zone of tropical and subtropical waters of all oceans. Hiding at the bottom, sometimes half-immersed in sand or silt, they paralyze their prey (other fish) with a discharge of current, the voltage of which is different types Stingrays range from 8 to 220 volts. A stingray can cause a significant electric shock to a person who accidentally comes into contact with it.
In addition to high-power electrical charges, fish are also capable of generating low-voltage, weak current. Thanks to rhythmic discharges of weak current with a frequency of 1 to 2000 pulses per second, they are even in muddy water They navigate perfectly and signal each other about emerging danger. Such are the mormirus and gymnarchs, who live in the muddy waters of rivers, lakes and swamps in Africa.
In general, as experimental studies have shown, almost all fish, both marine and freshwater, are capable of emitting very weak electrical discharges, which can only be detected with the help of special devices. These discharges play an important role in the behavioral reactions of fish, especially those that constantly stay in large schools.
Electric fish. Even in ancient times, people noticed that some fish somehow get their food in a special way. And only very recently, by historical standards, has it become clear how they do this. It turns out there are fish that create an electric discharge. This discharge paralyzes or kills other fish and even very small animals.
Such a fish swims, swims without hurrying anywhere. As soon as another fish is close to it, an electric discharge is created. That's it, lunch is ready. You can swim up and swallow a paralyzed or dead electric shock fish.
How is it possible for fish to create an electrical impulse? The fact is that in the body of such fish there are real batteries. Their number and size vary among fish, but the operating principle is the same. It is on the same principle that modern rechargeable batteries are designed.
Actually, modern batteries are created according to the model and likeness of fish batteries. Two electrodes with an electrolyte between them. This principle was once observed in the electric stingray. Mother nature hides many more interesting surprises!
Today there are more than three hundred species of electric fish in the world. They have the most different sizes and weight. All of them are united by the ability to create an electrical discharge or even a whole series of discharges. But it is still believed that the most powerful electric fish are stingrays, catfish and eels.
Electric ramps have a flat head and body. The head is often disc-shaped. They have a small tail with a fin. The electrical organs are located on the sides of the head. Another pair of small electrical organs are located on the tail. Even those stingrays that are not electric have them.
Electric stingrays can produce an electrical impulse of up to four hundred and fifty volts. With this impulse they can not only immobilize, but also kill small fish. A person, if he gets into the zone of action of the impulse, will also not feel a little. But the person will most likely remain alive, although he will certainly experience unpleasant moments in his life.
Electric catfish, like stingrays, create an electrical impulse. Its voltage can be up to 450 volts for large catfish, as well as for stingrays. When catching such a catfish, you can also get a very noticeable electric shock. Electric catfish live in the waters of Africa and reach sizes of up to 1 meter. Their weight can be up to 23 kilograms.
But the most dangerous fish live in reservoirs South America. This electric eels. They come in very large sizes. Adults reach a length three meters and weight up to twenty kilograms. These electrical giants can create an electrical impulse of up to one thousand two hundred volts.
With such a powerful impulse, they can even kill quite large animals that happen to be inappropriately nearby. The same outcome can await a person. The power of the electric discharge reaches six kilowatts. It won't seem enough. That's what they are - living power plants.
Lives in the depths of the seas and oceans a large number of amazing creatures, including stingrays and eels. These creatures are famous for using electricity for protection and hunting. However, most people cannot imagine how a living organism can act as a powerful battery.
Who generates the electricity?
Immediately as interesting fact It is worth noting that all fish produce electricity, it’s just that 99% of species generate very weak charges that are not noticeable during interaction. Sea creatures are able to generate electricity thanks to the special structure of their muscles, which produce and store electricity.
Some species, in the process of evolution, have learned to accumulate large charges and hit the enemy with them. The most successful in this activity are stingrays, eels, stargazers, gymnarchs, as well as a separate species of catfish.
How do fish generate electricity?
All types of electric sea creatures generate electricity as they move. Due to the fact that muscles constantly change their shape and interact with their environment, they accumulate electricity. In this case, the head and tail act as plus and minus, respectively. This helps keep the charge in the muscles, like a battery.
Let's take a closer look at what muscles are for accumulating charges. They may differ in appearance for each type of fish, but have a similar structure. Muscles consist of columns, which, in turn, are divided into plates. To store electricity, the columns are connected in parallel and the plates in series. Between them there is a potential difference, due to which energy accumulates during movement and charge accumulates.
In warm and tropical seas, in the muddy rivers of Africa and South America, there live several dozen species of fish that can occasionally or constantly emit electrical discharges of varying strengths. These fish not only use their electric current for defense and attack, but also signal each other and detect obstacles in advance (electrolocation). Electrical organs are found only in fish. These organs have not yet been discovered in other animals.
Electric fish have existed on Earth for millions of years. Their remains were found in very ancient layers earth's crust- in Silurian and Devonian deposits. On ancient Greek vases there are images of the electric sea stingray torpedo. In the writings of ancient Greek and Roman naturalist writers there are many references to the wonderful, incomprehensible power that the torpedo is endowed with. Doctors ancient Rome They kept these stingrays in their large aquariums. They tried to use torpedoes to treat diseases: patients were forced to touch the stingray, and the patients seemed to recover from electric shocks. Even nowadays on the coast Mediterranean Sea and the Atlantic coast of the Iberian Peninsula, elderly people sometimes wander barefoot in shallow water, hoping to be cured of rheumatism or gout by the electricity of a torpedo.
Electric ramp dashboard.
The outline of the torpedo's body resembles a guitar with a length of 30 cm to 1.5 m and even up to 2 m. Its skin takes on a color similar to environment(see article “Coloring and imitation in animals”). Various types of torpedo live in the coastal waters of the Mediterranean and Red Seas, Indian and Pacific Oceans, off the coast of England. In some bays of Portugal and Italy, torpedoes literally swarm on the sandy bottom.
The electrical discharges of the torpedo are very strong. If this stingray gets caught in a fishing net, its current can pass through the wet threads of the net and hit the fisherman. Electric discharges protect the torpedo from predators - sharks and octopuses - and help it hunt for small fish, which these discharges paralyze or even kill. Electricity in a dashboard is generated in special organs, a kind of “electric batteries”. They are located between the head and pectoral fins and consist of hundreds of hexagonal columns of gelatinous substance. The columns are separated from each other by dense partitions, to which the nerves approach. The tops and bases of the columns are in contact with the skin of the back and belly. The nerves that connect to the electrical organs have about half a million endings inside the “batteries”.
The discopyge ray is ocellated.
In a few tens of seconds, the torpedo emits hundreds and thousands of short discharges, flowing from the belly to the back. The current voltage in different types of stingrays ranges from 80 to 300 V with a current strength of 7-8 A. Several species of spiny stingrays live in our seas, among them the Black Sea stingray - the sea fox. The effect of the electrical organs of these stingrays is much weaker than that of the torpedo. It can be assumed that the electrical organs serve to communicate with each other, like a “wireless telegraph”.
In the eastern part of the Pacific tropical waters lives the ocellated discopyge ray. It occupies a kind of intermediate position between a torpedo and prickly slopes. The stingray feeds on small crustaceans and easily obtains them without using electric current. Its electrical discharges cannot kill anyone and probably only serve to ward off predators.
Sea fox ray.
It's not just stingrays that have electrical organs. The body of the African river catfish Malapterurus is wrapped, like a fur coat, in a gelatinous layer in which an electric current is formed. Electrical organs account for about a quarter of the weight of the entire catfish. Its discharge voltage reaches 360 V, it is dangerous even for humans and, of course, fatal for fish.
Scientists have found that African freshwater fish Gymnarchus continuously emits weak but frequent electrical signals throughout its life. With them, the gymnarhus seems to probe the space around itself. It swims confidently in muddy water among algae and stones, without touching any obstacles with its body. The same ability is endowed with the African fish mormyrus and relatives of the electric eel - the South American gymnota.
Astrologer.
In the Indian, Pacific and Atlantic Oceans, in the Mediterranean and Black Seas live small fish, up to 25 cm, rarely up to 30 cm in length - stargazers. They usually lie on the coastal bottom, lying in wait for prey swimming from above. Therefore, their eyes are located on the upper side of the head and look upward. This is where the name of these fish comes from. Some species of stargazers have electrical organs that are located on the crown of their heads and probably serve for signaling, although their effect is also noticeable for fishermen. Nevertheless, fishermen easily catch many stargazers.
The electric eel lives in tropical South American rivers. This is a gray-blue snake-like fish up to 3 m. The head and thoraco-abdominal part account for only 1/5 of its body. Along the remaining 4/5 of the body, complex electrical organs are located on both sides. They consist of 6-7 thousand plates, separated from each other by a thin shell and isolated by a lining of gelatinous substance.
The plates form a kind of battery, the discharge of which is directed from the tail to the head. The voltage generated by the eel is enough to kill a fish or frog in the water. People who swim in the river also suffer from eels: the eel’s electrical organ develops a voltage of several hundred volts.
The eel produces a particularly high voltage when it arches so that the prey is between its tail and head: a closed electrical ring is created. The eel's electrical discharge attracts other eels nearby.
This property can be used. By discharging any source of electricity into the water, it is possible to attract a whole herd of eels; you just need to select the appropriate voltage and frequency of discharges. Electric eel meat is eaten in South America. But catching him is dangerous. One of the fishing methods is designed to ensure that an eel that has discharged its battery becomes safe for a long time. Therefore, fishermen do this: they drive a herd of cows into the river, the eels attack them and use up their supply of electricity. Having driven the cows out of the river, the fishermen hit the eels with spears.
It is estimated that 10 thousand eels could provide energy to move an electric train within a few minutes. But after this, the train would have to stand for several days until the eels restored their supply of electrical energy.
Research by Soviet scientists has shown that many of the ordinary, so-called non-electric fish, which do not have special electrical organs, are still capable of creating weak electrical discharges in water in a state of excitement.
These discharges form characteristic biomass around the fish’s body. electric fields. It has been established that fish such as river perch, pike, gudgeon, loach, crucian carp, rudd, croaker, etc. have weak electric fields.
Dominic Statham
Photo ©depositphotos.com/Yourth2007
Electrophorus electricus) lives in dark waters swamps and rivers in northern South America. This is a mysterious predator with complex system electrolocation and capable of moving and hunting in low visibility conditions. Using "electroreceptors" to detect electric field distortions caused by it own body, he is able to detect a potential victim while remaining undetected. It immobilizes the victim with a powerful electric shock, strong enough to stun a large mammal such as a horse or even kill a human. Its elongated rounded shape the body of the eel resembles a fish, which we usually call a moray eel (order Anguilliformes); however, it belongs to a different order of fish (Gymnotiformes).Fish that can detect electric fields are called electroreceptive, but capable of generating powerful electric field, such as the electric eel, are called electrogenic.
How does an electric eel generate such high electrical voltage?
Electric fish aren't the only ones capable of generating electricity. Virtually all living organisms do this to one degree or another. The muscles of our body, for example, are controlled by the brain using electrical signals. The electrons produced by the bacteria can be used to generate electricity in fuel cells called electrocytes. (see table below). Although each cell carries only a small charge, by stacking thousands of cells in series, like batteries in a flashlight, voltages of up to 650 volts (V) can be generated. If you arrange these rows in parallel, you can produce an electric current of 1 Ampere (A), which gives an electric shock of 650 watts (W; 1 W = 1 V × 1 A).
How does an eel avoid shocking itself?
Photo: CC-BY-SA Steven Walling via Wikipedia
Scientists don't know exactly how to answer this question, but the results of some interesting observations may shed light on this problem. First, the eel's vital organs (such as the brain and heart) are located near the head, away from the electricity-producing organs, and are surrounded by fatty tissue that can act as insulation. Skin also has insulating properties, as acne with damaged skin has been observed to be more susceptible to self-stunning by electrical shock.
Secondly, eels are able to deliver the most powerful electric shocks at the moment of mating, without causing harm to the partner. However, if a blow of the same force is applied to another eel not during mating, it can kill it. This suggests that eels have some kind of defense system that can be turned on and off.
Could the electric eel have evolved?
It is very difficult to imagine how this could happen through minor changes, as required by the process proposed by Darwin. If the shock wave was important from the very beginning, then instead of stunning, it would warn the victim of danger. Moreover, in order to evolve the ability to stun prey, the electric eel would have to simultaneously develop a self-defense system. Every time a mutation arose that increased the power of the electric shock, another mutation must have arisen that improved the eel's electrical insulation. It seems unlikely that a single mutation would be sufficient. For example, in order to move organs closer to the head, a whole series of mutations would be required, which would have to occur simultaneously.
Although few fish are capable of stunning their prey, there are many species that use low-voltage electricity for navigation and communication. Electric eels belong to a group of South American fish known as "knife eels" (family Mormyridae) that also use electrolocation and are thought to have evolved this ability along with their South American cousins. Moreover, evolutionists are forced to declare that electrical organs in fish evolved independently of each other eight times. Considering the complexity of their structure, it is striking that these systems could have developed during evolution at least once, let alone eight.
Knives from South America and chimaeras from Africa use their electrical organs for location and communication, and use a number of various types electroreceptors. In both groups there are species that produce electric fields of different complex shapes waves. Two types of knife blades Brachyhypopomus benetti And Brachyhypopomus walteri are so similar to each other that they could be classified as one type, but the first of them produces a constant voltage current, and the second produces an alternating voltage current. The evolutionary story becomes even more remarkable when you dig even deeper. To ensure that their electrolocation devices do not interfere with each other and do not create interference, some species use a special system with the help of which each of the fish changes the frequency of the electrical discharge. It is noteworthy that this system works almost the same (using the same computational algorithm) as the glass knife from South America ( Eigenmannia) and African fish aba-aba ( Gymnarchus). Could such a system for eliminating interference have independently evolved in the course of evolution in two separate groups of fish living on different continents?
Masterpiece of God's creation
The energy unit of the electric eel has eclipsed all human creations with its compactness, flexibility, mobility, environmental safety and self-healing ability. All parts of this device in an ideal way integrated into the sleek body, which gives the eel the ability to swim with great speed and agility. All the details of its structure - from tiny cells that generate electricity to the most complex computing complex that analyzes the distortions of the electric fields produced by the eel - point to the plan of the great Creator.
How does an electric eel generate electricity? (popular science article)
Electric fish generate electricity much like the nerves and muscles in our body. Inside electrocyte cells there are special enzyme proteins called Na-K ATPase pump sodium ions across the cell membrane and absorb potassium ions. (‘Na’ is the chemical symbol for sodium and ‘K’ is the chemical symbol for potassium. ‘ATP’ is adenosine triphosphate, an energy molecule used to operate the pump). An imbalance between potassium ions inside and outside the cell results in a chemical gradient that pushes potassium ions out of the cell again. Likewise, an imbalance between sodium ions creates a chemical gradient that draws sodium ions back into the cell. Other proteins embedded in the membrane act as potassium ion channels, pores that allow potassium ions to leave the cell. As positively charged potassium ions accumulate on the outside of the cell, an electrical gradient builds up around the cell membrane, causing the outside of the cell to be more positively charged than the inside. inner part. Pumps Na-K ATPase (sodium-potassium adenosine triphosphatase) are designed in such a way that they select only one positively charged ion, otherwise negatively charged ions would also flow in, neutralizing the charge.
Most of the electric eel's body consists of electrical organs. The main organ and the Hunter's organ are responsible for the production and accumulation of electrical charge. Sachs's organ produces a low-voltage electrical field that is used for electrolocation.
The chemical gradient acts to push potassium ions out, while the electrical gradient pulls them back in. At the moment of balance, when chemical and electrical forces cancel each other out, there will be about 70 millivolts more positive charge on the outside of the cell than on the inside. Thus, a negative charge of -70 millivolts appears inside the cell.
However, more proteins embedded in the cell membrane provide sodium ion channels - these are pores that allow sodium ions to re-enter the cell. Normally these pores are closed, but when the electrical organs are activated, the pores open and positively charged sodium ions flow back into the cell under the influence of a chemical potential gradient. In this case, balance is achieved when a positive charge of up to 60 millivolts accumulates inside the cell. There is a total voltage change from -70 to +60 millivolts, and this is 130 mV or 0.13 V. This discharge occurs very quickly, in about one millisecond. And since approximately 5000 electrocytes are collected in a series of cells, up to 650 volts (5000 × 0.13 V = 650) can be generated due to the synchronous discharge of all cells.
Na-K ATPase (sodium-potassium adenosine triphosphatase) pump. During each cycle, two potassium ions (K+) enter the cell, and three sodium ions (Na+) leave the cell. This process is driven by the energy of ATP molecules.
Glossary
An atom or molecule that carries an electrical charge due to an unequal number of electrons and protons. An ion will have a negative charge if it contains more electrons than protons, and a positive charge if it contains more protons than electrons. Potassium (K+) and sodium (Na+) ions have a positive charge.
Gradient
A change in any value when moving from one point in space to another. For example, if you move away from the fire, the temperature drops. Thus, the fire generates a temperature gradient that decreases with distance.
Electrical gradient
Gradient of change in the magnitude of electric charge. For example, if there are more positively charged ions outside the cell than inside the cell, an electrical gradient will flow across the cell membrane. Because like charges repel each other, the ions will move in a way that balances the charge inside and outside the cell. The movements of ions due to the electrical gradient occur passively, under the influence of electrical potential energy, and not actively, under the influence of energy coming from an external source, such as an ATP molecule.
Chemical gradient
Chemical concentration gradient. For example, if there are more sodium ions outside the cell than inside the cell, then a chemical gradient of sodium ion will flow across the cell membrane. Because of the random movement of ions and the collisions between them, there is a tendency for sodium ions to move from higher concentrations to lower concentrations until a balance is established, that is, until there are equal numbers of sodium ions on both sides of the membrane. This happens passively, as a result of diffusion. The movements are driven by the kinetic energy of the ions, rather than by energy received from an external source such as an ATP molecule.
