Common, river or European eel (lat.Anguilla anguilla) is a predatory freshwater fish from the river eel family.
The eel has a long, meandering body like a snake. Fish is so reminiscent of its appearance of these reptiles that in many parts of Russia it is not considered to be a fish. And in vain, eel meat is very revered by the gourmets of some countries.
The body of the eel is cylindrical, and only the tail is slightly compressed from the sides. The head is small, in the front part it is slightly flattened. Eyes are small, silvery yellow.
The nose of different types of blackheads varies in width. The lower jaw is slightly longer than the upper. Both jaws, as well as the saxoid bone, are seated with sharp small teeth. Gill openings do not completely cover the gill cavity, they are very narrow about moving away far enough from the back of the head.Eel (Anguilla anguilla).
The eel has very long dorsal and anal fins, which merge with the caudal. Thus, one common, continuous fin is obtained, which stretches across the entire back of the fish. The fin rays, covered with thick skin, are very soft, so they differ with difficulty. At first it seems that the eel does not have scales at all, like many other species of fish. But this is an erroneous opinion - the scales of this fish are simply very small, oblong, arranged in a chaotic order. They are very tender, and the eel’s body is covered with a thick layer of mucus, which gives the impression that the eel is “naked”.
The color of the back of eels can be different, depending on the subspecies, it can be either brown-green or bluish-black. The abdominal part is colored either in yellowish-white or in bluish-gray shades.The body of an eel is more like a snake.
Eel is found in the basins of the Baltic, Mediterranean and German seas. It can also be found, although less frequently, in the ponds of the Black, White, Azov, Barents Seas. Eel also lives in some lakes, namely in Ladoga, Onega and Peipsi.
Apparently, the eel in the rivers of the basin of the Black and Caspian Seas came recently, presumably through channels from the water bodies of the Baltic basin. He comes here very rarely, only some individuals get to the Volga, but do not breed there. Locals confuse such eel travelers with river lampreys (outwardly these species of fish are very similar). Acne reaches the main channel of the Volga even to Saratov, but it is unlikely to go to the Caspian Sea in this way. But in some rivers flowing into the Volga in its upper reaches, eels come across more often, probably getting into them from lakes.Eel is a fish that is considered a delicacy in some countries.
The same acne travelers are rarely found in the Dnieper, Danube and Dniester. Back in the last century, zoologists found some individuals in the left tributary of the Desna. Most likely, eels came to the Dnieper from the Neman through swamps called Pinsky. In general, the upper reaches of the Baltic and Black Sea basin are nearby and are connected by numerous channels through which fish can migrate.
It happened that Kiev fishermen found eels in the stomachs of caught catfish, which means that eels should be found nearby: either in the Dnieper or in Pripyat. The Mogilev fishermen told zoologists that they met these fish in the Dniester. And in the 70s of the last century, eels were already caught in the Sea of Azov near the village of Petrovskaya.
But on the Danube, eels were launched on purpose. Representatives of the Galati Fisheries Society (a city and port in eastern Romania) launched over half a million young eels into the Danube. Zoologists believe that eels are quite capable of acclimatizing and living in this area. But for spawning, they are likely to go to sea downstream of the Danube.
According to professor of zoology Karl Kessler, river eel is not a completely freshwater fish, it can be called a passing fish. Because she does not spend all her life in river water and periodically leaves for the sea. But there is a significant difference between eel and other migratory fish. Basically, such fish grow in the sea and from there rise upstream to spawn. Eel, on the contrary, grows in rivers, and for breeding it goes downstream into the sea. Nothing can stop an eel in its journey - it overcomes rapids and waterfalls with ease.River eel is also called common eel or European eel.
According to the professor, even a very high Nara Falls, inaccessible, for example, for salmon, is not an obstacle for eel. True, while scientists do not know for certain how eel overcomes waterfalls, because unlike the same salmonids, it is not capable of jumping out of the water. “In all likelihood, he bypasses them, crawling over the wet coastal cliffs,” the zoologist writes of his assumptions, “at least it is true that he knows how to creep very cunningly on moist ground and can live out of the water for up to half a day or more. The reason for survivability eel outside water is that the gill leaves, due to the elongated shape of the gill cavity and the narrowness of the gill holes, remain moist for a very long time, capable of supporting the breathing process. ”
Eel tries to avoid rivers with sandy and rocky soil at the bottom. But his favorite habitat is a river with clay and silty soil and an abundance of mud. In summer, most often eel can be found between sedge and reeds, where he especially likes to be. For example, one of the places where eels are successfully caught is the reeds of the southern coast of the Krondstat Bay.
In order to catch the eel, the fishermen pave paths in the reeds, on which they set up special “tramp” traps. Here, fishermen distinguish between two species of these fish - running or settled. Settled eels are also called "herbalist". Eel - nocturnal fish. In the daytime, he simply lies calmly in the reeds, at night he goes fishing. By the way, in winter, the fish also remains stationary and digs into the mud, sometimes to a depth of more than 40 centimeters.Eel is a carnivorous fish.
Eel is carnivorous, it feeds on both other fish and their caviar. This fish does not disdain the small animals living in the mud: various larvae, worms, crustaceans, snails. As for the fish that eel eats, these are mainly species that live, like eel, at the bottom of reservoirs - lampreys, sculpids. If, in the field of view of the eel, a fish of other species is caught, he will not refuse it, therefore, sometimes it falls into the seine, the hooks of which the fishermen make small fish. But the feast itself begins with eels in spring and early summer, when cyprinids begin to spawn. Eel eats it in huge quantities. At the end of summer and autumn, when caviar can no longer be enjoyed, eels eat mainly crustaceans of the species "Idothea entomon", or, as they are called by fishermen, "sea cockroaches".
In general, what eels eat is very easy to track, because it has a completely unique property. Trapped in a trap, or in a cage, the eel belches a significant part of the food that did not have time to be digested: for example, it spews snails, minnows, crustaceans. In a word, catching an eel, you can see what he managed to eat today. By the way, catching an eel is much easier than holding it - it is almost impossible to do with bare hands due to the fact that these fish are extremely slippery and dexterous (not without reason, in Russia they say "slippery like eel", meaning a cunning and dodgy person).
On the earth, eel moves completely freely, both forward and backward, in the direction where one can most likely take refuge. At the same time, he moves like a snake, deftly wriggling his long body. Killing a caught eel is also a rather difficult task, because those wounds that could easily euthanize a fish of another species are often not fatal for an eel. So the eel is amazingly tenacious - except that a fracture of the spinal column leads to a more or less rapid death of this fish. Surprisingly, even the muscles of cut off pieces of eel are still contracting for some time. So, it was noted that the jaw of an eel in an already cut off head made movements for a quarter of an hour. It is believed that eel can be killed by placing it in salt water. But nothing of the kind - even in strong saline, eel lives for about another couple of hours.
By the uniqueness of its behavior, eel has long attracted the attention of naturalists and biologists. Also, eel has repeatedly become the object of experiments. So, for example, interesting observations of eel were recorded by O. Terletsky. The scientist observed the habits of eels in the Zapadnaya Dvina basin, where eel lives in many lakes, from which it flows into large rivers through small rivers, streams, and sometimes even overland, and then spawns into the sea. Blackheads start their “great” campaign in May and “go” all summer (the same blackheads that have not reached adulthood remain in lakes and rivers). In that case, if the river flows "in normal mode", the eel goes at a depth, trying to move around muddy or grassy places. When the water level rises significantly, blackheads are held in coastal whirlpools. At that night they hunt, moving farther on the way to the sea, and during the day they sleep, buried in mud, in silt or hidden under stones or driftwood.The surface of the eel is incredibly slippery.
Terletsky with the help of experiments was able to prove that eels are able to move from a reservoir to a reservoir sometimes even by land - if there is no other way. Moreover, they crawl over fairly considerable distances - for half a kilometer and even more. Terletsky kept eels in a separate pool on a stream, and then carried them to a considerable distance from their habitat, released them and watched their behavior. The experiments were carried out at night and also at dawn, when the soil is still wet. At first, blackheads crawled in different directions, but very soon instinct turned them in order to survive - to the river. Eels crawled pretty quickly, wriggling like snakes, exclusively directly to the target, only occasionally turning off the path to get around an obstacle in the form of a piece of land with sand or not covered with grass. When they fell on the slope leading to the water, they accelerated, trying to quickly get to their native element. Thus, it was proved that acne for three or even more hours can remain out of the water in the warm time of the day. Its transition to land-based water can last even all night, especially if abundant dew has fallen.
Reproduction and development of eelHead of river eel.
Until recently, the reproduction of eel has remained a mystery to scientists covered in darkness. And today, this side of acne life has not yet been fully explored. This is due to the fact that to continue the genus, fish of this species go to sea. The Danish ichthyologist I. Schmidt and other researchers managed to shed light on this process only recently, in the 20s of the last century. So scientists found that for breeding eel is looking for places in the sea with a temperature of 16-17 degrees. One female tosses up to 500 thousand eggs about 1 millimeter in size, and then dies. After a while, eel larvae appear from the eggs, resembling a willow leaf in appearance. Only the black eyes of the larvae are clearly visible on the translucent body, so they are less visible to predators. It is worth noting that eel larvae have generally been considered a separate species of fish for a long time - they are so unlike adults. When these little eels reach about 8 centimeters in length, they stop eating, decrease in size by a couple of centimeters and move to a new stage of development. Such a grown fry received the name "glass eel" from zoologists. It is still transparent, but it is already acquiring a specific snake-like body shape. At this time, small eels begin their journey to the mouths of the rivers, move along them further, gradually acquiring an adult color.Eel is a fish that grows very slowly.
Eel grows very slowly, reaching a meter in length only in the fifth or sixth year of life. There are individuals with a length of 180 centimeters and a thickness greater than the human hand. With a length of a meter, eel weighs about one and a half kilograms, and the largest specimens can reach a mass of eight kilograms.