JPH0473280B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric screen generating device for generating an electric screen for blocking the 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 method prevents fish and shellfish from escaping and entering the inside of the cage, but in the early stage of aquaculture, farmed fish are still young fish with a body length of several centimeters, and in order to block the swimming of these young fish, In this case, it is necessary to use a very fine-mesh net to be placed in 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. occurs,
In order to eliminate these inconveniences, conventionally, the sea areas where the fish cages are installed are selected where the water depth is not too deep, the seabed topography is almost flat, the waves are calm, and there are few tidal changes. Even if the nets are washed away by typhoons, etc., or damaged by contact with ships, it takes a lot of effort and money to maintain and maintain the nets, and the nets ensure that fish and shellfish can swim safely. The problem is that it cannot be blocked.

In addition, when carrying out large-scale aquaculture such as at 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 an electric screen generator shown in FIG.

That is, as shown in FIG. 3, a plurality of vertical rod-shaped conductive electrodes 1a are arranged in seawater at approximately equal intervals, and the conductive electrodes 1a are electrically connected to each other to form a first electrode row 2a. Similarly, a plurality of vertical rod-shaped conductive electrodes 1b and 1c were arranged in seawater at approximately equal intervals at the same pitch as in the case of the first electrode row 2a, and each of the conductive electrodes 1b and 1c was arranged at approximately equal intervals as shown in the figure. The second and third electrode rows 2b, 2c are electrically connected to each other by a connecting body, and the electrode rows 2a, 2b, 2c are arranged in parallel to each other. For example, the first and third electrode rows 2 on both sides are
a, 2c are at ground potential, and the second electrode row 2 in the center
Each electrode row 2a to 2c is connected so that b has a predetermined potential.
A DC voltage, an AC voltage, or a pulse voltage is applied between the electrode rows 2a to 2c to generate a double electric screen between the electrode rows 2a to 2c.

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. If the electrode rows 2a to 2c are arranged so that a specific area is surrounded by the electric screen, the fish will exhibit an electric shock reaction and will be unable to swim through the electric screen. The shellfish are trapped, and the swimming of fish and shellfish is reliably blocked without using nets as in the past, and it is not affected by ocean conditions such as tide level, tide, water depth, or weather conditions such as typhoons. Suitable for large-scale aquaculture such as ocean farms.

At this time, by varying the distance between the first and second electrode rows 2a and 2b and between the second and third electrode rows 2b and 2c, the electric field strength between the first and second electrode rows 2a and 2b can be changed. 2. The electric field strength between the third electrode rows 2b and 2c is different, and a double electric screen is formed in which the degree of electrical stimulation received by fish and shellfish is different. For example, the electrode rows 2a to 2c are arranged with the third electrode row 2c inside so as to surround the
If the electric field strength between the second and third electrode rows 2b and 2c is made smaller than that between the first and second electrode rows 2a and 2b, when cultured fish and shellfish in the specific range invade the electric scree, The cultured fish and shellfish are subjected to weak electric stimulation between the second and third electrode arrays 2b and 2c, which have a small electric field strength, and can easily move from the electric screen to the original specified range without being damaged by the electric stimulation. When foreign fish and shellfish invade the electric screen from outside the specific range, the foreign fish and shellfish receive strong electrical stimulation between the first and second electrode rows 2a and 2b, which have a large electric field strength. The fish will show a reaction such as mild numbness or paralysis, and will be unable to swim through the electric screen, making it possible to reliably protect farmed fish and shellfish.

By the way, for example, if a fish body that has entered the electric screen is parallel to the direction of the electric field, a current will flow through the fish body due to the potential difference between two points separated by a distance equivalent to the body length. Even if the intensity is low, the electric potential difference between the head and the tail becomes large, and the current that can pass through the fish body increases to some extent, causing an electric shock reaction.In contrast, in the case of small fish with short bodies, if the electric field intensity of the electric screen is low, the head Since the potential difference between the tails does not become large,
The current flowing inside the fish does not become large and does not cause an electric shock reaction.

In other words, even if the electric field strength is the same, large fish and small fish will receive different degrees of electrical stimulation from the electric screen, and large fish and small fish will exhibit different electric shock reactions. Each electrode row 2a to 2
c, if the electric intensity between the second and third electrode rows 2b and 2c inside the electric screen is set to a value such that large fish receive weak electrical stimulation that is surprising, Small fish are inside the second and third
The first and second electrode rows 2a, 2a, and 2c swim between the electrode rows 2b and 2c without receiving electrical stimulation.
2b, and suddenly receive strong electrical stimulation between the outer first and second electrode rows 2a and 2b, causing paralysis or the like.

Conversely, if the electric field strength between the second and third electrode rows 2b and 2c is set to a value that will cause small fish to receive surprising electrical stimulation, large fish will If the patient suddenly receives strong electrical stimulation between the electrode rows 2b and 2c, paralysis or the like may occur.

[Problem that the invention seeks to solve]

As mentioned above, fish and shellfish that are paralyzed by strong electrical stimulation usually lose their buoyancy and sink toward the sea floor, so paralyzed fish and shellfish swim away from the area that receives strong electrical stimulation on their own. There are problems in that they cannot escape and cannot be resuscitated, eventually becoming fatal, and it is not possible to protect farmed fish and shellfish from damage caused by electrical stimulation.

Therefore, the technical problem of this invention is to enable fish and shellfish to automatically escape from the electric screen and revive themselves even if they become paralyzed due to strong electrical stimulation.

[Means for solving problems]

The present invention has been made with the above-mentioned points in mind, and includes a plurality of electrode rows in which a plurality of conductive electrodes are arranged in seawater at approximately equal intervals and arranged in parallel to each other; A connection body that electrically connects the conductive electrodes of each electrode row to each other, and a power source for generating an electric screen that applies a voltage between each of the electrode rows so that each of the electrode rows has a different potential. The electric screen generating apparatus is characterized in that each of the electrode rows is arranged on a plurality of contour lines of a slope of the seabed.

[Effect]

Therefore, in this invention, the plurality of electrode rows are
The electric screen is placed parallel to the seawater and on multiple contour lines of the slope of the seabed, and a voltage is applied between each electrode row so that each electrode row has a different potential using a power source for generating an electric screen. An electrical screen is formed between the electrode rows.

At this time, if the fish and shellfish that have entered the electric screen become paralyzed due to electrical stimulation, and the paralyzed fish and shellfish sink toward the sea floor, the fish and shellfish will flow along the slope. The paralyzed fish and shellfish automatically escape from the electric screen between each electric field pole row, recover from the paralyzed state, and resuscitate, thereby preventing damage to the fish and shellfish caused by electrical stimulation.

〔Example〕

Next, this invention will be described in the first part showing its embodiment.
This will be explained with reference to FIG.

First, FIG. 1 showing one embodiment will be explained.

In Fig. 1, the same symbols as in Fig. 3 indicate the same or equivalent items, and the difference from Fig. 3 is that the conductive electrodes 1a to 1c are placed on the seabed on the third electrode row 2c side. An artificial slope 3 is formed, and each electrode row 2a is placed on the contour line of the slope 3.
This is the point where 2c was placed.

Then, as shown in FIG. 1, the cultured fish F enters the electric screen and receives electrical stimulation between the first and second electrode rows 2a and 2b, for example.
If the cultured fish F becomes paralyzed and sinks to the seabed as shown by the arrow, the cultured fish F will flow along the slope 3 and automatically escape from the electric screen, and the paralyzed cultured fish F will eventually recover. , it is possible to revive the farmed fish F and prevent damage to the cultured fish F due to electrical stimulation.

Next, FIG. 2 showing another embodiment will be explained.

In FIG. 2, the same symbols as in FIG. 1 indicate the same things, and the difference from FIG. 1 is that the first electrode row 2a
A fourth electrode row 2d formed of a plurality of conductive electrodes 1d arranged at equal intervals in the same manner as the first to third electrode rows 2a to 2c is arranged on the outside of the inclined surface 3. An inclined surface 4 having an opposite inclined direction is formed to form an inclined portion having an inverted V-shaped cross section, and the inclined surface 4
This is the point where the fourth electrode row 2d is arranged on the contour line.

At this time, if the electric field strength between the fourth and first electrode rows 2d and 2a is made comparable to that between the second and third electrode rows 2b and 2c, the electric field strength between the fourth and first electrode rows 2d and 2a or 1. Foreign fish between the second electrode rows 2a and 2b
When F' invades, the foreign fish F' paralyzed by electrical stimulation flows along the slope 4 to the outside of the fourth electrode row 2d, automatically escapes from the electric screen, and is eventually revived. Therefore, unnecessary damage to the foreign fish F' due to electrical stimulation can also be prevented.

Note that each of the conductive electrodes 1a to 1d is not limited to the rod shape described above.

Furthermore, it goes without saying that the number of electrode rows may be five or more.

〔Effect of the invention〕

As described above, according to the electric screen generator of the present invention, since the electrode rows 2a to 2d are arranged on the contour lines of the inclined surfaces 3 and 4 of the seabed, fish and shellfish that have invaded the electric screen are paralyzed by electrical stimulation. Even if the paralyzed fish and shellfish are
, these fish and shellfish can automatically escape from the electric screen and be resuscitated, which can prevent damage to fish and shellfish caused by electrical stimulation, making it possible to more reliably produce farmed fish and shellfish. It can be protected and the effect is extremely large.

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic diagrams of an embodiment of the electric screen generator of the present invention, and FIG.
The figure is a perspective view of an electric screen generator for comparison with the present invention. 1a to 1d... conductive electrode, 2a to 2d... electrode row, 3, 4... inclined surface.

Claims (1)

[Claims] 1. A plurality of electrode rows in which a plurality of conductive electrodes are arranged in seawater at approximately equal intervals and arranged in parallel to each other, and each of the conductive electrodes in each of the electrode rows is electrically connected to each other. a connecting body;
In the electric screen generation device, the electric screen generator includes a power source for generating an electric screen that applies a voltage between each of the electrode rows so that each of the electrode rows has a different potential. An electric screen generator characterized in that each electrode row is arranged.