RU2768036C1 - Method for erecting redds for laying sturgeon fish eggs - Google Patents

Abstract

FIELD: fish industry.

SUBSTANCE: invention relates to fisheries, in particular to the artificial breeding of sturgeon fish, and can be used to restore sturgeon populations. The method for constructing redds for laying eggs of sturgeon fish includes the preparation of artificial spawning sites, delivery of fertilized eggs from fish hatcheries to spawning sites and laying eggs in the nests of the redds. Artificial spawning sites are arranged in three layers at a distance from each other in coastal overgrown areas of rivers. The lower two layers of spawning sites are made in the form of flexible mattresses, the first layer of which is made of bags filled with sand or gravel, the second layer is made of light fascines forming a nest for laying and incubating sturgeon eggs. At the same time, light fascines are made in the form of a bundle of ripe reeds with a diameter of 8-10 cm, and inside each fascine, fertilized eggs are laid in paper bags between dressings. On top of the two-layer mattresses, a backfill of large pebbles with a fraction size of 40-60 mm is arranged, which forms the third layer of spawning sites.

EFFECT: method provides a reduction in labor intensity during the construction of artificial redds and an increase in the commercial return of sturgeon fish.

1 cl, 4 dwg

Description

The invention relates to fisheries, more precisely to the artificial breeding of sturgeon fish, and can be used to preserve and restore sturgeon populations.

A known method of incubation of eggs in artificial nests-incubators installed in rivers [1]. The method includes artificial insemination of eggs at fish hatcheries, transportation of eggs to spawning grounds, laying of eggs at the "eye" stage in artificial incubator nests, which are installed on the rapid-erratic sections of rivers open from ice at the end of March. This technology is not entirely suitable for sturgeon fish of the Volga-Caspian basin, sturgeon fish mainly live in the Caspian Sea, and breed in fresh waters of rivers. In addition, artificial nest-incubators during the period of their technological production are costly, their installation on the spawning grounds of rivers is laborious and lengthy in terms of installation time.

There is a known method of breeding sturgeon fry in the factory and releasing them into the river basins of the Caspian Sea [2]. Fish hatcheries release up to 45 million sturgeon juveniles per year into the rivers. In this case, the commercial return from the release of juveniles is less than 0.1%, and this is the main disadvantage of this method.

Relatively close analogues are

artificial spawning grounds for lithophilic (including sturgeon) fish, which are arranged in the downstream of hydroelectric facilities (in sections of rivers below the hydroelectric dam) and in bypass channels [3]. For sturgeon and whitefish, spawning grounds are located in the riverbed in the form of ridges at a depth of 3 m and in the presence of a flow velocity of 1-2 m/s. They also create artificial spawning grounds in bypass channels, where natural spawning grounds have lost their former purpose due to the deterioration of hydrological conditions and their impossibility of restoration (or where natural spawning grounds were absent altogether). The bottom of the channels is covered with pebbles and gravel with a layer of 70 cm, in such channels it is possible to create stable optimal conditions for fish spawning and caviar incubation. However, the complexity of creating such spawning grounds is very high, the technology of their construction is complex and the need for constant monitoring and control, since over time the substrate and eggs become silted (washing of the substrate is required).

The purpose of the invention is to reduce the complexity of the device of artificial spawning grounds and increase the commercial return of sturgeons.

This goal is achieved by the fact that in the method of erecting spawning grounds and laying sturgeon eggs, including the preparation of artificial spawning grounds, the delivery of fertilized eggs from fish hatcheries to spawning grounds, the laying of eggs in spawning grounds, artificial spawning grounds are arranged in three layers at a distance from each other in coastal overgrown sections of rivers , the lower two layers of spawning grounds are made in the form of flexible mattresses, the first layer of which is made of bags filled with sand or gravel, the second layer is made of light fascines that form a nest for laying and incubating sturgeon eggs, while light fascines are made in the form of a bunch of mature reeds, with a diameter of 8-10 cm, and inside each fascine, between dressings, fertilized caviar is laid in paper bags, a backfill of large pebbles is arranged on top of two-layer mattresses to form a third layer of spawning grounds. At the same time, artificially constructed spawning grounds with nests for incubation of eggs create the most optimal conditions for the conservation and restoration of sturgeon populations.

In FIG. 1 shows a section of a river with artificially equipped spawning grounds along its channel; in fig. 2 - a flexible mattress made of a bag of sand (or gravel) and light fascines, forming a nest for caviar; in fig. 3 - light fascine from ripe reeds; in fig. 4 - a paper bag with sturgeon caviar.

Artificial spawning grounds 1 for sturgeons consist of flexible two-layer mattresses 2, on top of which a third layer of large pebbles 3 is arranged. inside which paper bags with caviar 6 are laid. Light fascines 5 are interconnected (to form a nest for caviar) and attached to the bags 4 using assembly ropes 7.

The method of erecting spawning grounds for laying sturgeon eggs is carried out and works as follows.

First, on the spawning sections of the rivers (coastal overgrown sections of the rivers), the places for laying artificially equipped spawning grounds 1 are planned. The distance between the spawning grounds should be at least 3.0 m, optimally from 3 to 5 m or more, depending on the hydrological and geomorphological conditions of a particular section of the river. Dry river sand or gravel is brought to the coastal section of the river (to the spawning site), which is filled with pre-prepared geogrid bags (bag sizes, approximately 30 × 30 × 150 cm). After that, the required volume of mature reeds is collected and brought to the place of laying artificial spawning grounds 1. Then light fascines 3 are made in the form of bundles (tied in three places) with a diameter of 8-10 cm and a length of 130-150 cm. dressings) lay pre-prepared bags with fertilized caviar 6 delivered from sturgeon plants. And caviar 6, fertilized in the factory (washed from the remnants of sperm and stickiness), is brought in a special container with water to the place of laying the caviar. Further, small bags are prepared from thin environmentally friendly paper, 15-20 cm long and 4-5 cm in diameter, where fertilized caviar is laid in portions (up to a thousand eggs, washed from stickiness and sperm). At the same time, it is advisable to put in the bags along with the caviar the starter feed (compound feed OST-6 or its equivalent) for the fish larvae pecking out of the eggs, so that they can feed for the first time. 3-4 light fascines (with bags of caviar) are attached to each bag 6 with sand or gravel using a mounting rope 7, which is pulled out with a margin of 2-3 m. Thus, prepared flexible mattresses 2 with wet bags of caviar (for now not dried for 2 hours) with the help of assembly ropes 7, they are laid (manually by 2 people) in pre-designated places in the coastal concave sections of the river channel, for spawning grounds 1. At least 2-3 flexible mattresses 2 are placed in one spawning ground, on top of which a layer of large pebbles 3 (fraction sizes 40-60 mm), 7-10 cm thick is applied. Using this technology, the required number of artificial spawning grounds 1 is erected in concave (preferably overgrown) sections of rivers, where the river flow velocity is at least 1 m / s. Since for normal development and hatching of eggs, the oxygen content in water should not be lower than 8-9 mg / l (temperature 15-20 ° C), and such an oxygen content is provided at water flow rates of 1 m / s or more.

The flexible design of artificial spawning grounds 1 with light fascines 5 (used as nests for eggs) is the most suitable for incubation of sturgeon eggs and further development of their larvae and fry.

Artificial spawning grounds, arranged in sections of rivers (plain and foothill zones) with laid sturgeon caviar, ensure the development and restoration of sturgeon populations. The bags themselves made of thin natural paper (where caviar 6 is placed) quickly decompose in water. In the spring, fertilized eggs 6 in the nests of light fascines quickly stick to the reed straws and develop, after a certain time (8-10 days), larvae hatch from them. This is facilitated by light fascines 5 made of reeds, in the rods of which air is kept for a long time, which maintains the saturation of water in the nests with oxygen and creates normal conditions for the incubation of eggs 6. The stones of the upper layer protect the eggs from being carried away by the water stream and from predators. At first, the larvae feed on the nutrient reserves of the yolk sac (and the food placed in the sacs). Ripe reed, from which light fascines 5 are made, is a nutritious natural material for zoobenthic forms living in river water. Due to this, sturgeon fry grow out of the larvae, which float out into the aquatic environment from the reeds of fascines and stone (large pebbles). The stones of the upper layer of spawning grounds 1 help them to keep (hide between stones), protect themselves from predatory invertebrates and vertebrates. Further, sturgeon fry adapt to the conditions of the river, feed on zooplankton and insect larvae located along the water's edge in the leaves of overgrown reeds (and other plants), and grow up to developed individuals capable of swimming the river to the mouth (up to the Caspian Sea), where they live and replenish sturgeon populations.

Artificial spawning grounds made by the proposed method from flexible mattresses and stone create optimal conditions for spawning and development of fry that can replenish the population of sturgeon fish in the Caspian basin.

The method of erecting spawning grounds for laying sturgeon eggs can be most effectively used in the flat and foothill areas of the rivers of the Volga-Caspian basin.

Literature

1. Patent of the Russian Federation 2386248. A method of incubation of eggs in artificial nests-incubators installed in rivers. / Pavlov D.S., Skorobogatov M.A. et al. Bull. No. 11 publ. 04/20/2010.

2. Khodorevskaya R.P. The importance of natural spawning and artificial sturgeon breeding in the formation of sturgeon stocks in the Caspian Sea / Astrakhan Bulletin of Ecological Education No. 2 (32) 2015. p. 74-89 (Astrakhan).

3. https://mydocx.ru/1-133733.html.

Claims (1)

A method for erecting spawning grounds for laying sturgeon eggs, including preparing artificial spawning grounds, delivering fertilized eggs from fish hatcheries to spawning sites, laying eggs in spawning nests, characterized in that artificial spawning grounds are arranged in three layers at a distance from each other in coastal overgrown sections of rivers, lower two layers of spawning grounds are made in the form of flexible mattresses, the first layer of which is made of bags filled with sand or gravel, the second layer is made of light fascines that form a nest for laying and incubating sturgeon eggs, while light fascines are made in the form of a bundle of ripe reeds with a diameter of 8-10 cm, and inside each fascine, between dressings, fertilized eggs are laid in paper bags, on top of two-layer mattresses, a backfill of large pebbles with fractions of 40-60 mm is arranged, which forms the third layer of spawning grounds.

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