JPH0442796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric screen generating device that generates an electric screen for blocking swimming of fish and shellfish in seawater when cultivating fish and shellfish.

[Conventional technology]

Generally, when cultivating fish and shellfish, a cage is set up in seawater, and the fish and shellfish are cultured within the cage.Usually, a net is stretched around the seawater to form a cage, and the net is used to extend the fish and shellfish to the outside of the cage. This prevents fish and shellfish from escaping and entering the inside of the cage, but at the early stage of aquaculture, farmed fish are still young fish with a body length of several centimeters, and this prevents the swimming of these young fish. In this case, it is necessary to use a very fine mesh net to be placed in the seawater.

However, in sea areas where tidal changes can be as large as several meters, the nets are easily damaged, and even if the damage is slight, young fish can easily escape, resulting in the inconvenience of requiring a great deal of effort and expense to maintain and maintain the nets. arises,
In order to eliminate these inconveniences, conventionally, the sea areas where the fish cages are installed are selected in areas where the water depth is not too deep, the waves are calm, and there are few tidal changes, but even in areas that meet these conditions, typhoons The nets may be washed away due to water pollution, etc., or damaged due to contact with ships, which requires a great deal of effort and expense to maintain and maintain the nets, and the nets cannot reliably block the swimming of fish and shellfish. There is a problem.

In addition, when carrying out large-scale aquaculture such as on marine farms, the total length of the nets used is extremely long, and the labor and expense required to maintain and maintain the nets are correspondingly large. Using nets for isolation is not the best strategy for large-scale aquaculture.

Therefore, the present applicant has proposed the following electric screen generator.

That is, a plurality of vertical rod-shaped conductive electrodes are arranged in seawater at approximately equal intervals to form a first electrode row, each conductive electrode is electrically connected to each other, and a plurality of rod-shaped conductive electrodes are similarly arranged in seawater at approximately equal intervals. Vertical rod-shaped conductive electrodes are arranged at substantially equal intervals with the same pitch as the first electrode row to form second, ..., Nth electrode rows, and the second, ..., Nth electrodes The conductive electrodes of each row are electrically connected to each other, the electrode rows are arranged parallel to each other, and a power source for generating an electric screen is used to connect the conductive electrodes between the electrode rows so that the potential of each electrode row is different. For example, a DC voltage is applied to the electrodes to generate an electric screen between each of the electrode rows.

Fish and shellfish that have entered such an electric screen are electrically stimulated, and when the electric field strength is low, they exhibit a startled state, and as the electric field strength increases, they exhibit mild numbness, paralysis, and even asphyxia. They exhibit an electric shock reaction and are unable to swim through the electric screen.If each electrode row is arranged so that a specific area is surrounded by the electric screen, fish and shellfish will be trapped in the area surrounded by the electric screen. As a result, the swimming of fish and shellfish is reliably blocked without using nets as in the past.
It is not affected by ocean conditions such as tide level, tide, water depth, or weather conditions such as typhoons, making it suitable for large-scale aquaculture such as on marine farms.

However, the fish and shellfish that penetrate the electric screen and become paralyzed by the strong electrical stimulation lose their ability to swim and sink to the ocean floor. will eventually die.

[Problem that the invention seeks to solve]

Therefore, it is necessary to take measures to prevent fish and shellfish from being damaged by electrical stimulation by allowing the paralyzed fish and shellfish to escape outside the electric screen or into an area where the electric field intensity is low and the electrical stimulation is light. In the case of the above-mentioned electric screen generator, the electric field strength near the seabed of the electric screen is almost the same as in other parts, so if paralyzed fish and shellfish sink toward the seabed, they cannot escape from the electric screen on their own. This poses a problem in that it is not possible to prevent damage to fish and shellfish caused by electrical stimulation, and the fish and shellfish are unable to do so, resulting in continued extremely strong electrical stimulation to the extent of paralysis, leading to death.

Therefore, the technical object of the present invention is to enable fish and shellfish to automatically recover even if they are paralyzed by electric field stimulation of an electric screen, and to protect fish and shellfish from damage caused by electrical stimulation.

[Means for solving problems]

The present invention has been made with the above-mentioned points in mind, and includes a plurality of conductive electrodes arranged in seawater at approximately equal intervals and arranged in parallel to each other; and a power source for generating an electric screen that applies a voltage between each of the electrode rows so that the potential of each electrode row is different, and a region of low electric field intensity is formed near the seabed between each of the electrode rows. This is an electric screen generator.

[Effect]

In this invention, an electric screen is formed between each electrode row by applying a voltage from a power source for generating an electric screen, and the fish and shellfish that are paralyzed by the electric stimulation on the electric screen sink to the seabed and form near the seabed. In this area, the fish and shellfish recover from their paralyzed state and are able to escape out of the electric screen on their own.

〔Example〕

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

As shown in FIG. 1, the lower ends of a plurality of rod-shaped conductive electrodes 2a in the vertical direction are supported by a plurality of support stands 1 made of an insulating material such as concrete buried in the seabed, and each conductive electrode 2a is are arranged at approximately equal intervals in seawater to form a first electrode row 3a, and similarly the lower ends of a plurality of rod-shaped isoelectric electrodes 2b, 2d, 2e in the vertical direction are supported by a plurality of support stands 1, respectively. The conductive electrodes 2b, 2d, and 2e are arranged in seawater at approximately equal intervals to form a second conductive electrode.
In addition to forming the fourth and fifth electrode rows 3b, 3d, and 3e, a partition wall 4 made of an insulating material such as concrete is provided on the seabed between the second and fourth electrode rows 3b and 3d. The lower ends of the rod-shaped conductive electrodes 2c are supported at approximately equal intervals, and the conductive electrodes 2c are arranged in seawater to form a third electrode row 3c, and the electrode rows 3a to 3e are arranged parallel to each other. At the same time, the conductive electrodes 2a to 2e of the electrode rows 3a to 3e are electrically connected to each other, and the potentials of the electrode rows 3a to 3c are made different by a power source for generating an electric screen (not shown).
For example, a DC voltage is applied between each electrode row 3a to 3e to form an electric screen between each electrode row.

At this time, the electric field strength between the first and second electrode rows 3a and 3b and between the fourth and fifth electrode rows 3d and 3e is
The electric field strength between the second and third electrode rows 3b and 3c and between the third and fourth electrode rows 3c and 3d is such that the fish and shellfish show a mild electric shock reaction such as slight numbness. It is assumed that the distance between each of the electrode rows 3a to 3e and the applied voltage are set so as to exhibit a rather strong electric shock reaction.

Further, it is assumed that each support stand 1 and partition wall 4 are provided at approximately the same height L from the seabed.

The distribution of lines connecting equipotential points in arbitrary vertical sections orthogonal to each electrode row 3a to 3e, that is, the distribution of equipotential lines, is as shown in FIG. 2, and the first and second electrode rows 3a, 3b between the second and third electrode rows 3 and between the fourth and fifth electrode rows 3d and 3e.
The spacing between the isoelectric lines is narrower between b and 3c and between the third and fourth electrode rows 3c and 3d, indicating that the electric field strength is higher.Furthermore, in the region L above the seabed, each electrode row 3a to 3e The spacing between the equipotential lines is very wide, indicating that the electric field strength near the ocean floor is very low.

Therefore, since the lower ends of each of the conductive electrodes 2a to 2e are supported by the support base 1 and the partition wall 4 made of an insulating material such as concrete, a region with low electric field strength is formed near the seabed. , second
Between the electrode rows 3a and 3b and the fourth and fifth electrode rows 3
The fish and shellfish that invaded between d and 3e received relatively mild electrical stimulation and showed only a slight numbness response.
While it is easy to swim and escape on your own, between the second and third electrode rows 3b and 3c and between the third and fourth electrode rows 3
Fish and shellfish that have entered between c and 3d become paralyzed by strong electrical stimulation, lose their ability to swim, and sink to the ocean floor. He recovers and is eventually able to swim out on his own.

At this time, for example, if the electrode rows 3a to 3e are arranged so as to surround a specific range with the fifth electrode row 3e inside, and the cultured fish and shellfish are accommodated within the range, as shown in FIG. As such, farmed fish F within the above range
and foreign fish F' outside the range can be protected from damage caused by electrical stimulation on the electric screen, and the partition wall 4 prevents recovered cultured fish F from escaping from the range and foreign fish F'. Fish F' can be prevented from entering the range.

In addition, in the above embodiment, each of the conductive electrodes 2a to 2e
Although a case has been described in which the lower end of the electric field is supported by the support base 1 and the partition wall 4 made of an insulating material such as concrete to form a region with low electric field strength near the seabed, it goes without saying that the invention is not limited to this.

Further, each of the conductive electrodes 2a to 2e is not limited to the above-described rod shape.

Furthermore, an alternating current voltage or a pulse voltage may be applied between each electrode row 3a to 3e.

Further, the number of electrode rows may be 2 to 4 or 6 or more.

〔Effect of the invention〕

As described above, according to the electric screen generator of the present invention, when fish and shellfish that have invaded the electric screen are paralyzed by electrical stimulation, these fish and shellfish can be recovered from the paralyzed state in an area with low electric field strength near the seabed. It is possible to prevent the fish and shellfish from continuing to receive strong electrical stimulation in a paralyzed state and lead to death, and it is of course possible to prevent the fish and shellfish from swimming.
It becomes possible to protect fish and shellfish from damage caused by electrical stimulation, and the effect is extremely large.

[Brief explanation of drawings]

The drawings show one embodiment of the electric screen generator of the present invention, with FIG. 1 being a perspective view and FIG. 2 being a distribution diagram of equipotential lines. 2a to 2e...conductive electrodes, 3a to 3e...electrode arrays.

Claims (1)

[Claims] 1 A plurality of electrode rows each formed of a plurality of conductive electrodes arranged at approximately equal intervals in seawater and arranged in parallel to each other, and a voltage applied between each of the electrode rows so that the potential of each electrode row is different. 1. An electric screen generating device, comprising: a power source for generating an electric screen that applies an electric current, and a region of low electric field intensity is formed near the seabed between each of the electrode rows.