SU1755754A1 - Method for directing fish movement - Google Patents

Abstract

Usage: in industrial fishing when fishing with fixed nets, trawls and other fishing gear and to protect fish from falling into hydraulic structures. SUMMARY OF THE INVENTION: Fish are affected by acoustic signals with a fundamental filling frequency of 40-200 Hz, with an amplitude of 102-5 104 Pa / m. The pulses are fed with a period of 1–20 s, 1 h.p f-crystals.

Description

The invention relates to industrial fishing, mainly to fishing with fixed nets, trawls and other fishing gear. It can also be used to protect fish from entering waterworks.

The known method of directional movement of fish, involving the impact on them of acoustic signals, selected based on the basic frequency of filling, amplitude and period of the next.

The known method is ineffective in the shallow areas of the water area, because the sound quickly fades into the water, if the depth of the reservoir does not exceed a quarter of the sound wavelength.

The aim of the invention is to increase the efficiency of directional movement of fish with short distances of influence.

This goal is achieved by the fact that when exposed to fish with sound signals, pulses with a fundamental filling frequency of 40-200 Hz and an amplitude of 10 -5-410 Pa / m are used.

In this case, the pulses are fed with a period of 1–20 s.

Acoustic signals with an amplitude above the threshold of audibility in the frequency range 400-800 Hz do not cause directional movements of the fish. Many species of fish (flounders, rats) do not perceive such signals.

Acoustic signals with frequencies of 60–300 Hz and amplitudes of 100–500 Pa / m are ineffective under conditions of high noise levels, such as a vessel with a trawl. Selective perception of signals is absent. Acoustic signals with frequencies of 10–60 Hz and amplitudes of 103–5–105 Pa / m are not effective for directional movement of fish in shallow water areas. In addition, at high amplitudes, they cause panic reaction in small groups. Thus, in this case, there is no scaring effect on the shallow areas of the water area and panic reaction is not excluded.

When erecting acoustic signals on fish with parameters in the specified combination, a stronger reaction appears (L

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Fish chi, selective perception of signals under conditions of high levels of noise, the deterring effect of acoustic signals under conditions of shallow water bodies, is preserved, and the panic reaction is excluded.

The method can be used to increase the efficiency of trawling, fixed non-aqueous, transiting non-aqueous fishing of fish, as well as for the protection of fish in water intake structures.

With respect to trawling, the method is as follows.

In the area where large clusters of sparse fish or small frequent spit marks are noted, a trawl with an upper or lower selection fixed in the nex part of the ne or an extension of the emitter of acoustic signals, for example pneumatic or electric spark, is placed on the trawl axis. via cable or from an autonomous power source according to a predetermined program or in another way. The location of the radiator is determined by the parameters of the transmitted signals, the size of the cross section of the net cone at the installation location is The teacher should not exceed the distance of the fish’s defensive response to acoustic signals. For example, an emitter transmitting signals with a frequency of 100 Hz is installed in that part of the winding part where the cross section of the net cone does not exceed 30 m. The parameters of the acoustic signals are emitted. The bodies must provide a defensive reaction of the fish at all distances from the source to the net shell. For large sizes of the cross section of the net cone, several sources are established with a signal of 100 Hz,

In the process of pickling, the fish, falling into the trawl, moves to the motile part, then unfolds, as a rule, in the critical zone and moves for a long time along with the trawl. Fish trawling is controlled by a sensor. After stopping the entry of fish, one or several impulses are sent to cause the fish to roll. mainly from the radiator. Here, the fish between the radiator and the trawl sack moves in the direction of the sack and is fished. The fish moving between the radiator and the mouth of the trawl scares away the mouth direction, but does not come out of the trawl due to the small distance of the fish’s defensive response to acoustic signals with the specified parameters, and also due to the constant movement of the trawl forward. the trail sequence of actions is repeated.

In order to prevent fish from leaving the trawl below the selection and to the sides, emitters of acoustic signals are placed around the perimeter of the mouth. When signals with the specified parameters are emitted, the fish are scared in the direction of the axis of the trawl, while due to the small distance of scaring, there is no fish leaving ust.

0 When protecting fish in water intake structures, the method is carried out as follows. In the water area where the water intake structure is located, a section with water flow rates below the cruising level is selected.

5 speeds of movement of frightened fish, and establish a line of emitters of acoustic signals. The distance between the radiators is chosen so that the total distance of the defensive reaction of the fish to

0 acoustic signals from neighboring sources exceeded the distance between them. For example, signal emitters with frequencies of 10 and 200 Hz are set at a distance of no more than 22 m. Emitters operate in an automatic mode with a period of 1-20 seconds or are controlled through a cable. As the fish moves towards the working emitters, the amplitude of perceived signals gradually increases. and at a certain distance, it reaches values exceeding the threshold of the defensive reaction, the fish are turned and they leave the danger zone. The pulse period is set based on the speed

5 fish movements: the interval between pulses should not exceed the time in which the fish will travel a distance equal to the defensive reaction distance.

With reference to fishing with fixed water, the method is implemented in a similar way by installing a line of emitters with the specified parameters seawater than a trap, this allows an increase in the catch zone of the fixed net. The fish moving in the direction of the seine falls into the zone of action of the acoustic emitters1 and changes the direction of movement, moving further in the direction of the seine trap. At the same time, the height of the fixed net increases

0 by referring to the fishing zone, initially moving seaward from the trap.

When fishing with inlet seines and snorurveds, the method is carried out by installing acoustic emitters

5 signals indicated by the parameters at the spot and beige ends. When sampling the seine include emitters of signals that deter fish in the center of the zone of catch.

Example 1, In tank and natural conditions with a sea depth from 1 to Hume

assess the response of pelagic fish to acoustic signals by changes in speed and direction of movement. Pneumatic and electrodynamic radiators were used mainly. Acoustic signals were applied in the form of pulses with a fundamental filling frequency of 100 Hz, an amplitude of 5,103 Pa / m and a period of 8 seconds. The distance from the radiator to the fish at the time of signaling was changed from 3 to 30 m. The reaction of the fish was estimated using an echo sounder, by catches using chewing nets and visually.

The possibility of scaring fish from certain parts of the water area with acoustic signals with the parameters indicated above was checked. For this purpose, the emitter was installed in the area of the water area where fish of various species were constantly present. Before sending signals using an echo sounder, the quantitative and species composition of the fish was visually assessed, then signals were sent and periodically every 5–30 minutes the presence of fish in the area around the radiator. Conducted 12 experiments. The departure of fish from the zone of action of the radiator to a distance of 15–20 m and more is noted. At the same time, no movement of the fish in the direction of the working radiator was observed during the whole time of the experiment,

The possibility of changing the direction of movement of the fish was also checked. For this, signals with the specified parameters were applied for a duration of 30-60 minutes. The presence of fish in the zone of action of the radiator was assessed by catches using a chewing net and an echo sounder. 17 experiments were conducted on the river during the smelt run to spawn. Before the signals were given, fish were caught in all sections of the network, blocking the entire river. Then, from the radiator installed near one bank of the river, acoustic signals were constantly given. The catches in this area during the emission of signals were not noted. An increase in the frequency of fish entering the net near the river bank opposite the radiator was noted. Smelt changes the direction of movement and leaves the zone of action of the radiator. Similar results were obtained for bottom-bottom fish.

In the cage and the fixed net, the possibility of reversing the fish, i.e. changing the direction of movement to the opposite, was also checked. Experiments were performed with groups of sardines, mackerel, herring, and other fish species. Signals were given while the fish was moving in the direction of the radiator. Conducted 22 experiments. In

All experiments showed a change in the direction of movement of the fish to the opposite and a departure to the zone of sediment far from the radiator, Example 2. The method according to

The operations are identical to the method described in Example 1, except that the acoustic signals were applied with a fundamental pulse filling frequency of 40 Hz, an amplitude of 102 Pa / m and a period of 1 or 1 s. Under cage conditions at a sea depth of 7 m, 17 experiments with the Japanese anchovy were carried out. The reaction was evaluated by changes in speed and direction of movement. When signals are given from a distance to

5 fish 5-15 observed a clear defensive reaction - moving away from the source. When the emitter was working, the anchovy in the continuation of the entire experiment was in the far from the emitter zone

0 charge. After cessation of radiation after 2-4 minutes, the anchovy began to move in the direction of the radiator, the subsequent signaling caused a reaction similar to the one described above. At x distance from

5 fish to the radiator more than 30 m, the reaction was weak, with more rapid adaptation. Similar data obtained for smelt

Example 3. The method according to the methods and

The 0 steps are identical to the method described in Example 1, except that the acoustic signals were applied with a fundamental pulse filling frequency of 200 Hz, an amplitude of 5 × 105 Pa / m and a tracking period of 20 s. Under cage conditions, at a reservoir depth of 4.5 m, 22 experiments were conducted with various types of fish. At distances x from the radiator to the fish of 5–15 m, acoustic signals with the indicated parameters scare the fish away from the radiator, and the anchovy moved farther away from the radiator from the cage zone. In natural conditions, the smelt went out of sight of the observer. The reaction of the southern odnoperogo terpuga appeared weaker, especially at a distance of more than 30 m. Similar results were obtained for other species of fish.

Example 4. The method according to the methods and

0 operations are identical to the method described in example 1, except that the acoustic signals were applied with a fundamental filling frequency of Impuls of 30 Hz, an amplitude of 102 Pa / m, and a trace period of 5 nor 8 s. Under natural conditions, at a water body depth of 2.5, 8 experiments with smelt were carried out. The fish response was assessed visually, according to catches by gill nets and using an echo sounder. Simultaneously, the amplitude of the signal was measured at different distances.

1755754

from the radiator. Acoustic signals with the specified parameters are quickly damped in shallow water areas. With the distance from the radiator A m, the amplitude of the signal with a frequency of 30 Hz is reduced to a value below the threshold of the defensive reaction. The fish quickly leaves the zone with a radius of 4 m, but then adapts to the signals and there is no directional movement from the radiator. Acoustic signals with frequencies below 40 Hz are ineffective for the directional movement of fish in shallow water areas.

Example 5. The method according to the techniques and operations is identical to the method described in example 1, except that the acoustic signals were applied with a fundamental pulse filling frequency of 250 Hz, an amplitude of 103 Pa / m and a pulse repetition period of 8 s. Under the tank conditions more than 40 experiments with different types of fish. In the majority of fish (herring, mackerel, sardine, etc.), at the first 3–7 pulses, mild pea, -; fright was observed, which later passed. The fish moved several meters away from the radiator, then adapted and the behavior did not differ from the background. Some species of fish, such as the southern single-footed parrot, did not react to acoustic signals with frequencies above 200 Hz.

Example 6 The method according to the techniques and operations is identical to the method described in example 1, except that the acoustic signals were applied with a fundamental pulse filling frequency of 100 Hz, an amplitude of 10 Pa / m and a pulse period of 8 s. More than 30 experiments with various fish species have been carried out in cage and natural conditions. Bottom fishes (sea ruffs, larvae, etc.) often observed an approximate reaction, but there was no directional departure from the radiator. The days of pelagic fish (herring, mackerel) during the first 3-6 pulses showed an increase in the speed of movement, but the fish moving in the direction of the radiator did not change the direction of movement. Acoustic signals with an amplitude of less than 10 Pa / m are ineffective for the directional movement of fish.

Example 7. The method according to the techniques and operations is identical to the method described in Example 1, except that the acoustic signals were applied with a fundamental pulse filling frequency of 100 Hz, an amplitude of 105 Pa / m, and a pulse repetition period of 8 s. 8 natural and cage conditions of the response of pelagic fish to

acoustic signals with the specified parameters were observed in 23 experiments. At a distance of 15–25 m to the radiator, the reaction of small groups of sardines and smelt manifests itself in the cast of individuals predominantly in the direction from the radiator and the fish leaving the zone of influence. However, at a distance of 5–15 m, a panic reaction of single individuals and groups of small numbers was observed, accompanied with movement of fish in all directions. At the same time, part of the group moved in the direction of the signal emitter. Thus, when emitting signals with high amplitudes, moving fish.

Example 8. The method according to the techniques and operations is identical to the method described in Example 1, except that acoustic signals were applied with a fundamental pulse filling frequency of 100 Hz, an amplitude of 10 Pz / m, and a pulse period of 25 s. 12 experiments were conducted on the water area with a depth of 2.5 m. In front of the chewing network, two emitters of acoustic signals were installed with the parameters indicated above. The catches were used to evaluate the efficiency of the directional movement of fish from the water area with radiators. Mackerel and sardines hit the net between the radiators. Visual observations showed that during the period between pulses, the fast-moving fish covered a distance greater than the defensive reaction distance. Similar results were obtained when testing a method for fishing smelt with a filler net in a river. Acoustic signals with a pulse period of more than 20 s do not always give a positive result,

Example 9. The method according to the techniques and operations is identical to the method described in examples 1, 2, except that the pulse following period was 0.5 s. 14 experiments with the Japanese anchovy and 9 experiments with smelt were carried out. More rapid adaptation of fish to the indicated signals was noted compared with experiments in which pulses with a period of 1 s were emitted. For higher amplitudes (103–10 Pa / m), adaptation was slower, however, the overall response was weaker.

The proposed method for the directional movement of fish has significant advantages over the known one. It allows you to effectively scare away fish at shallow depths of the water area, which is safe when protected from hitting fish.

in hydraulic structures. In addition, the panic response of single individuals and small groups is excluded. The method also reduces energy consumption by emitting signals with a lower amplitude and the possibility of increasing the pulse duration.

Claims (2)

Claim 1. Method of directional movement of fish, involving the impact on them of acoustic signals selected 0 taking into account the fundamental frequency of filling, amplitude and pulse period, characterized in that, in order to increase the efficiency of directional movement of fish at short distances of influence, pulses are used with a fundamental filling frequency of 40-200 Hz and an amplitude of 102-5 104 Pa / m. 2. A method according to claim 1, characterized in that the pulses are fed with a period of 1-20 seconds.