Mostly sturgeon species of fish live in the sea salt water and swim to spawn in fresh water.The most smallest dimensions endowed starlet representatives, who have an average size of 30 cm to 1 m and weight of a pound up to 4 kg.The largest representative of the species - beluga, which reaches 2 tons of weight and 9 m in length.
Today catching sturgeon - the world's largest fishing.In addition to meat, this species has its valuable caviar.During spawning fish vyov prohibited.But poaching is flourishing everywhere, even to him and are actively fighting.
External characteristics and structure
Representatives of sturgeon - one of the biggest fish in the water expanse of rivers and seas, they have an elongated body, which is covered with five rows of bony Schitik 1 on the back, two on each side and 2 on the belly.Between them there are bony plates.Sturgeon - fish with an elongated conical snout, like a shovel.Bottom head arranged fleshy lips mouth that several species has a crescent shape and is also on the sides.Below are 4 of the muzzle mustache.The jaw has a sliding form without teeth.
Radiation fin chest greatly thickened and looks like spines, the dorsal is slightly pushed back.The swim bladder is located beneath the spine and is connected to the esophagus.Skeleton has invertebrates, cartilage structure with preservation of the chord.4 gill membrane attached toward throat and merge on the throat, and there are still 2 adventitious gills.
General
In most cases, all sturgeon species spawn at the time of moving into fresh sources in shallow water.Their population is quite prolific, and are old enough and large individuals can produce millions of larvae.Spawning occurs in the spring.It is worth noting that some species, except for spawning, are part of the waters of rivers and cabin.They live mainly on the bottom of ponds, feeding on small fish, worms, mollusks and insects.
Puberty
sturgeon family, which includes a list of about two dozen species, represented mainly by longevity.Period of readiness to spawn an individual comes in different ways, depending on the habitat and species of fish.At this time, you can see how some of the shallow water of fresh river swarms with representatives of the sturgeon.After spawning individuals producing roe down the river to the sea, increase in size, are developing.The following year, they were sent back to spawn.
growth of sturgeon, as well as maturation, is very slow.Some species ready to breed at the age of only 20 years.In females, puberty comes at a period of 8 to 21 years, males 5 to 18 years.But about weight can be said that sturgeon fish species - the most rapidly growing inhabitants of ponds.The fastest way to reach puberty sturgeon Dnieper and Don, much longer - the inhabitants of the Volga.
Spawning
Not all the female sturgeon spawn every year.Each year sturgeon breeds only.Representatives of sturgeon spawn in the spring-summer season in fresh water rivers with fast current.It has the structure of the adhesive, so great is attached to limestone or gravel.
fry
larvae emerging from eggs, have a yolk sac that leads to the endogenous period of supply.Independently eat outside food can fry the time when the endogenous bladder completely absorbed.Then comes the period of active exogenous supply.After that, the fry may linger in the river waters, but often larvae falling into the sea in the summer of the same year.So breeding sturgeon.Photo of different representatives can be found in this article.
Power fry
first food for sturgeon fry - a zooplankton such as Daphnia.Once they begin to eat the crustaceans representatives:
* gammarids,
* chironomids,
* mysids.
exception is predatory beluga juveniles who do not have the yolk sac and during their stay in the river to begin their meal.
further development of mature sturgeon to age occurs in marine waters.Globe representatives sturgeon divided into spring and winter types.For the first familiar occurrence in the river in the spring.Spawning occurs from them almost immediately.Winter also includes the river in autumn, spend the winter and spawn next spring.
Classification sturgeon family
originally isolated two types of sturgeon:
* sturgeon;
* skafirinyh.
They numbered in the amount of about 25 species of fish, which were carried out only in the temperate latitudes of Asia, Europe and North America.Over time, the population of some of them disappeared.
Types
sturgeon species are very popular in the fishery.Today it is known 17 species of sturgeon representatives.The most popular are the following:
1. Beluga - the oldest form of freshwater fish.The life cycle it can last 100 years.The biggest beluga can reach 5 m long and have a weight of 2 tons.The body shape of the fish seems to torpedo covered with protective bony plates in 5 rows, dark-gray, and the bottom - white.Bottom of the muzzle have antennae that provide fish nose, and mouth in the shape of a sickle.Females are larger than males.Beluga - a predator that feeds mostly anchovies, gobies, herring, dried fish and anchovy.Caviar hurl females every 2-4 years in spring.
2. Russian sturgeon - the fish with a spindle-shaped body with a short blunt snout.The antennae are located at the end of the mouth.Most often, the fish has a grayish-black color on top, grayish-brown flanks and white belly.Russian sturgeon reaches a maximum of 3 m in length and can weigh up to 115 kg.In this life cycle of up to 50 years.In the wild sturgeon can form hybrids with the sturgeon, beluga, sturgeon and spine.It happens very rarely, but such hybrids can be found.Scope of fish habitat: Azov, Caspian and Black Seas.
3. Siberian sturgeon.The body is covered with numerous fish fulkrami and bone plates, retractable mouth.This fish teeth are missing.Before the mouth are 4 segment.Siberian sturgeon habitat: pools of the Yenisei, Ob, Lena and the Kolyma.Maximum fish grows to 3 m in length, up to 200 kg in weight and can live 60 years.Spawning is in the middle of summer.Food sturgeon are organisms that live at the bottom of the river, clams, amphipods, marine worms and chironomid larvae.
4. Stellate sturgeon inhabits the basins of the Azov, Black and Caspian Seas.Fish sturgeon is winter and spring.For an elongated body stellate sturgeon is characterized by a long nose, bulging forehead, narrow and smooth mustache and poorly developed lower lip.Side and top body of the fish is covered with a dense cover of scutellum.The back and sides are bluish-black color, and the belly - white.Stellate rarely reaches more than 5 m in length and 50 kg weight.
5. Sturgeon - one of the smallest among the sturgeon fish, it reaches 1.25 m in length and weighing up to 16 kg.It has an elongated narrow nose, long tendrils that reach the mouth in contact Schitik sides and divided into two lower lip.In addition to the usual plate of sturgeon on the body, sturgeon is closely linked scutellum on the back.Depending on the fish habitat areas can have different colors, but often the back of her gray-brown color, and the belly is yellowish-white.Fins gray everywhere.Also starlet is blunt and sharp-nosed.Fish is found only in northern Siberia.
