There is a magnificent large lake in the highlands of the Caucasus. It is located at an altitude of 1900 meters above sea level. The lake is called so: Sevan. Armenia is the country in whose territory it is located.
It is the lake that is the habitat of fish called Sevan trout. By the way, she is highly regarded by fishermen. In addition to Lake Sevan, trout, a photo of which is presented in the article, is found in nearby rivers.
Description
Let's talk more about this fish. What is she like? Sevan is a special type of trout. Its name comes from the Latin salmo ischchan. In Armenian, the word ishkhan means "king." So it was called for beauty and greatness compared to other fish. After all, some of its individuals can reach a weight of up to seventeen kilograms. Sometimes Sevan trout is found, whose body length is one meter. As you can see, a real giant! In the fifteenth century, this fish was brought to various countries of the East.
By scientists, Sevan trout, the photo of which is in the article, is divided into four species, or, in other words, race. Moreover, they all have differences from European trout.
Winter Ishkhan
So, one of the species of this trout is called winter ishkhan. Sometimes it is also called winter bakhtak. This species of trout is the largest. There were cases when the caught individual was seventeen kilograms, and its length was 104 centimeters. Impressive size! Then when the winter ishkhan was fed up, its color is silver-white, and its back is the color of the color of steel. He has few dark spots, and they are surrounded by a rim along the edge, light in color. However, they are never X-shaped, when compared with trout. The food of winter ishkhan is amphipods, whose habitat is the bottom of the reservoir.
The maturity of this type of trout is four or five years. At the time when spawning begins in the fish, the males change color. They darken significantly, and their fins become almost completely black. Several red spots appear on their sides, and light rims on the remaining spots stand out quite clearly. Females remain unchanged. The laying of eggs takes place directly in the lake itself. The number of eggs can reach four thousand. Before the fall of the lake level, two herds of fish were distinguished: one spawning occurred from October to January, and the other from January to March. In this case, spawning occurred at different depths. For the former, the depth was 0.5-4 meters, and for the latter, 0.5-20 meters.
Winter bahtak is especially appreciated by fishermen. It used to be an important fishing target. However, after the level of Sevan fell, many places of trout spawning remained on the shore. Therefore, now this species of fish is quite rare.
Summer Ishkhan
The second type of Sevan trout is summer ishkhan. This fish is also called summer bakhtak. They named it so because it lays eggs in spring or summer. Its spawning takes place in the Bakhtak-Chai and Gedak-Bulah rivers, as well as in Sevan itself, in the estuary sections of the lake. This species of trout is smaller. Its weight, if you take the maximum, reaches two kilograms, and its length is about 60 centimeters. Summer ishkhan matures at the age of 2-7 years. This type is a less prolific species of trout.
Such a fish can lay a little more than a thousand eggs in spawning. Often on the sides of the fish summer bakhtak you can see red spots. The commercial stock of this species is reduced every year due to the fact that the path to the spawning site was almost blocked.
Bojac
Another subspecies of Sevan trout is the bojak. This is a dwarf species of trout, and its size is very small. It is known that the largest caught individual did not reach a length of thirty centimeters. And their average length varies from 24 to 26 cm. Usually males of a bojak quite often have red spots on the sides.
This species of trout spawns only in Lake Sevan (Armenia).
Having reached the age of three to four years, she begins to spawn. It should be said that at the same time she does not build nests to lay eggs, but tosses her around the bottom of Sevan. The bojack spawns from October to November. Moreover, scientists previously believed that this process takes place at a depth of about fifteen meters, but after drying of the coastal zones, bojak spawning grounds were identified at a depth of forty meters. However, their area is quite small and can never resume the lost coastal areas, and therefore the number of this fish has sharply decreased.
Gegharkuni
Well, the last subspecies of Sevan trout is called gegharkuni. Young growth resembles the spotty of other salmon. Their coloring has a slightly different shape than other types of trout Sevan. Gegharkuni on the body have dark transverse stripes and brown-yellow and red spots. Their feeding occurs after a year of stay in the lake. Their color is darker than that of Ishkhan, but the shade is also silver.
Its food is not only benthos, but also zooplankton, located mainly in the water column and moving along the stream. This Gegharkuni also differ from other types of trout. It spawns only exclusively in running water, that is, in rivers.
Sevan trout: abundance
Back in the 20s of the last century, artificial breeding of summer ishkhan and gegharkuni began to be made. Until the mid-forties, the commercial stock was estimated at 1.6 million individuals. However, further the living conditions in the rivers of young animals significantly worsened, and the path to spawning was actually blocked. In view of this, after the fifties, the Gegharkuni and the summer Ishkhan began to be bred only at hatcheries.
Despite all the measures taken to preserve the number of Sevan trout, the collection of caviar in hatcheries was reduced. All these conditions, including lowering the water level, and a reduction in the natural spawning grounds of fish, have led to the fact that the abundance of all species began to decrease sharply.
Eutrophication made a significant contribution to all this. Eutrophication is an increase in the primary productivity of water due to an increase in their nutrients, such as mainly fluorine and nitrogen. These components can be introduced into water bodies through industrial and municipal effluents, after flushing from fertilizer fields or with sediments, for example. At first, this can have a beneficial effect on the fish, as the feed becomes larger. However, after all this, the water quality is deteriorating. The coastal zone begins to overgrow, the water becomes cloudy, the transparency becomes less, and, accordingly, the oxygen level also decreases.
Endangered Species
In a particularly difficult situation, due to changes that occur in the lake itself and other bodies of water, the largest and smallest species of trout - bojak and winter ishkhan - turned out to be. This fish spawns in the lake itself. These species were threatened with extinction. And therefore, a fish called Sevan trout was declared a reserve and is listed in the Red Book.