SU1697654A1 - Spawning apparatus - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to fish management, namely, devices for the natural spawning of fish. The aim of the invention is to ensure the reproduction of fish in conditions of fluctuating water levels. An overflow dam fences off a section of the reservoir at the bottom of which, below the ridge of the dam, there is an artificial spawning substrate, and above the level of the dam up to the level of the supposed maximum filling of the reservoir, material suitable for spawning is laid. With a high water level in the pond, producers enter the fenced area and lay eggs. After the water level in the pond decreases, the drying of spawning grounds and caviar deposited on them are prevented. 3 il.

Description

FIELD OF THE INVENTION The invention relates to fish management, namely, devices for the natural spawning of fish.

The aim of the invention is to ensure the reproduction of fish in conditions of fluctuating water levels.

FIG. 1 shows a device for spawning fish, top view; in fig. 2 - the same, cross section; in fig. 3 shows an embodiment of a dike equipped with culvert holes.

The device for spawning fish includes an overflow dam 1 and a fenced off section 2 of the reservoir with a coastline 3 and lines of water at the maximum water level 4 and the minimum water level 5. Comb 6 of the overflow dam 1 is ruined under the maximum water level in the reservoir. In the fenced area 2 of the reservoir, at its bottom at level 7, below the crest of the dam, there is an artificial spawning area 8 containing the spawning substrate 9. At the section of the reservoir located above the level of the ridge of the overflow dam 1, material 10, which is unsuitable for caviar laying As such material, expanded clay, concrete, etc. can be used. The laying area on the drained part of the fenced-off section 2 of the reservoir of material unsuitable for spawning depends on the depth of drawdown of the water level and the steepness of the shore.

The cross-sectional shape of the overflow part of the dike 1 can vary from rectangular to parabolic. Comb overflow can be fixed with concrete slabs and stone drafts. The length of the overflow part of the dam 1 can be determined by the following formula O

about m

about ate

L

S-ah

0.5 5h v T 0.5 v T where S is the area of the cut off part of the reservoir;

Ah - level of drawdown in the clipped part;

V is the rate of attraction of fish;

T is the time of drawdown of the water level by the value of Ah.

FIG. 3 shows an embodiment of the device, in which the ridge of the dam 1 is located above the maximum water level 4 in the reservoir, but at the same time the dam 4 is provided with culvert holes 11c with closures 12.

Device for spawning fish works as follows.

With a high level of water in the pond, fish plots fenced off by dam 1 pod 2, fish producers enter the pond and lay eggs on spawning substrate 9. Fish flow through overflow dams is stimulated by counterflow of water from fenced plots 2 to the pond. At the same time, the producers do not lay eggs on the subsequently drained areas above the level 7 of the ridge of the overflow dam 1, since material 10, which is unsuitable for spawning, is laid in these areas.

After the water level in the pond has decreased, in the fenced areas 2, the level

The water does not fall below the crest of the dike 1, as a result of which the drying of spawning grounds and caviar deposited on them is prevented. This ensures the natural reproduction of fish and increases the fish productivity of reservoirs under conditions of fluctuations in the water level in reservoirs with daily and seasonal flow regulation.

In a variant of the device, when the crest of dam 1 is located above the maximum water level 4 in the reservoir, and the dam is provided with culvert holes 1 with gates 12 (Fig. 3), natural reproduction of fish is maintained when gates 12 are blocked over the water level 7 in the fenced off area 2 of the reservoir.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION Claims A device for spawning fish, including a dam for separating a portion of a reservoir, from. In order to ensure the reproduction of fish in conditions of fluctuations in the water level in the reservoir, the dam is made overflow, at the bottom of the fenced off area to the level corresponding to the level of the dam crest, the artificial spawning substrate is laid, and above the level of the dam crest to the level of supposed maximum filling pond laid material unsuitable for laying eggs. eight 1 .Vf & l - -. . X. ... "". A, JxWb% f: .-: - V -.:. : -.L - v V-v-.i: Y G: - 5-0 : figure 2. .:/;-one .V f & l - -. . ;. .  . :. : -.L - .i: fig.Z