JPH0442798B2 - - 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 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 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 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. 6, a plurality of vertically extending rod-shaped conductive electrodes 1a that are longer than the water depth are placed in seawater.
The conductive electrodes 1a are arranged at approximately equal intervals, and the conductive electrodes 1a are electrically connected to each other to form one electrode row 2a.Similarly, a plurality of vertical rod-shaped conductive electrodes 1b, which are longer than the water depth, are placed in seawater as electrodes. The conductive electrodes 1b are arranged at substantially equal intervals with the same pitch as the row 2a, and the conductive electrodes 1b are electrically connected to each other to form the other electrode row 2b,
The electrode row 2b is arranged at a certain distance from the electrode example 2a, and a power source for generating an electric screen (not shown) is used so that, for example, one electrode row 2a has a high potential and the other electrode row 2b has a low potential. For example, a DC voltage is applied between both electrode rows 2a and 2b to generate an electric screen between both electrode rows 2a and 2b.

Note that the one-dot chain line in FIG. 6 indicates both the electrode arrays 2a,
2b shows equipotential lines obtained by connecting equipotential points in a vertical cross section perpendicular to 2b.

Fish and shellfish that enter 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 severe symptoms such as asphyxia. If the electrode arrays 2a and 2b 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.

By the way, fish and shellfish that enter an electric screen and become paralyzed by strong electrical stimulation lose their ability to swim and sink to the ocean floor. However, if they continue to receive strong electrical stimulation while in a paralyzed state, the fish and shellfish eventually become paralyzed. I'll die.

[Problem that the invention seeks to solve]

Therefore, it is necessary to take measures to prevent damage to fish and shellfish caused by electrical stimulation by allowing the paralyzed fish and shellfish to escape outside the electric screen or into an area where the electric field strength is low and the electrical stimulation is light. In the case of Fig. 6 described above, as can be seen from the distribution of equipotential lines shown in the same figure, the electric field strength of the electric screen between both electrode rows 2a and 2b is almost the same near the seafloor as in other parts, so a state of paralysis occurs. If the fish and shellfish that have fallen into the water sink to the sea floor, they will not be able to escape from the electric screen on their own and will eventually die, and the problem is that it will not be possible to prevent the fish and shellfish from being damaged by electrical stimulation. be.

Therefore, the technical problem of this invention is to enable the fish and shellfish to automatically recover and resuscitate even if they are paralyzed by the electrical stimulation of the electric screen, and to protect the fish and shellfish from damage caused by the electrical stimulation. do.

[Means for solving problems]

The present invention has been made with the above-mentioned points in mind, and includes a plurality of electrode rows each formed by disposing a plurality of conductive electrodes at approximately equal intervals in seawater and arranged in parallel to each other; comprising a connection body that electrically connects each of 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 the potentials of each of the electrode rows are different; The electric screen generating device is characterized in that the depth of the lower end of each of the conductive electrodes is made different for each of the electrode rows.

[Effect]

According to the present invention, an electric screen is formed between each electrode row by applying a voltage from a power source for generating an electric screen, and at this time, since the depth of the lower end of each conductive electrode is different for each electrode row,
A region with low electric field strength is formed near the ocean floor,
Fish and shellfish that are paralyzed by electrical stimulation in areas with high electric field strength sink to the sea floor, and in areas with low electric field strength, fish and shellfish recover from their paralyzed state, revive, and are able to escape outside the electric screen on their own, causing fish and shellfish to sink to the sea floor. Damage to shellfish due to electrical stimulation is prevented.

〔Example〕

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

First, FIGS. 1 to 3 showing one embodiment will be explained.

In Fig. 1, 3a is a plurality of vertically extending first rod-shaped bodies made of insulating material such as concrete, which are arranged in the sea at equal intervals, and 3b are arranged in the sea at the same intervals as the first rod-shaped bodies 3a. A plurality of vertically extending second rod-like bodies 4a, which are shorter than the first rod-like body 3a made of an insulating material, each have a rod-shaped first conductive electrode 5a joined to the upper side of each first rod-like body 3a, and are connected to each other. A first electrode row formed electrically connected, 4b
A rod-shaped second conductive electrode 5b, which is longer than the first conductive electrode 5a, is connected to the upper side of each second rod-shaped body 3b, and is electrically connected to each other and arranged in parallel to the first electrode row 4a. The second electrode row 4c is a third electrode row formed by disposing rod-shaped third conductive electrodes 5c in seawater at the same intervals as each of the first rod-shaped bodies 3a and electrically connected to each other, They are arranged parallel to the second electrode row 4b.

At this time, the first rod-shaped body 3a and the first conductive electrode 5a
The total length of the second rod-shaped body 3b and the second conductive electrode 5b, and the length of the third conductive electrode 5c are set to be equal, and each conductive electrode 5
The depth of the lower end portions of electrodes a to 5c becomes deeper in each electrode row 4a to 4c.

Note that 6a and 6b are power sources for generating an electric screen that apply, for example, a DC voltage between the first and second electrode rows 4a and 4b and between the first and third electrode rows 4a and 4c, respectively. 4a is at ground potential, and a voltage is applied so that the second and third electrode rows 4b and 4c have different potentials, forming an electric screen between each electrode row 4a to 4c.

When a voltage is applied so that the voltage between the second and first electrode rows 4b and 4a and the voltage between the third and second electrode rows 4c and 4b are equal, each electrode row 4a
The distribution of equipotential lines in the vertical cross section perpendicular to ~4c is as shown in FIG. This indicates that the electric field strength is low, and the other parts, that is, each electrode row 4a to 4
The intervals between the equipotential lines are narrow and approximately uniform in the area c, indicating that the electric field strength is high and approximately constant.

That is, in a vertical cross section perpendicular to each electrode row 4a to 4c, the lower ends of each conductive electrode 5a to 5c are connected with a straight line, as shown by the dashed line in FIG. Assuming that a straight line passing through the lower end of 3b is like the two-dot chain line in the figure, the areas A1 and A2 above the one-dot chain line in the figure have the highest electric field strength, and the two-dot chain line in the figure The electric field strength of regions B1 and B2 between the two-dot chain line is lower than that of regions A1 and A2, and the electric field strength of the region C below the two-dot chain line in the figure is even lower.

By the way, if a marine farm is formed by arranging the electrode arrays 4a to 4c so as to surround a specific range with the first electrode array 4a on the inside, and aquaculture is carried out within this ranch, for example, the cultured fish can be grown. When entering area A1 in Figure 3 from near the sea surface, the cultured fish receives strong electrical stimulation at the same time as entering area A1 and falls into a paralyzed state. The animal eventually recovers from its paralyzed state, revives itself, and swims back to the ranch on its own.

In addition, when farmed fish enter area B1 in Figure 3 from the middle part between the sea surface and the seabed, they receive a relatively mild electrical stimulation and take repellent behavior, returning to the farm.
Even if they continue to invade, if they reach area A1 or A2, they will receive strong electrical stimulation and fall into a state of paralysis, sinking into areas B1, B2, and C where the electric field strength is lower, and eventually recover from their paralysis and be revived. Then return to the ranch and move from near the ocean floor to area C and then B2.
Fish and shellfish that invade the area will take repellent behavior by mild electrical stimulation.

Therefore, it is possible to prevent farmed fish and shellfish within the farm from escaping outside the farm, and at the same time protect the farmed fish and shellfish from damage caused by electrical stimulation. By setting the electric field strength in area A2 higher than area A1 in Figure 3, it is possible to apply strong electrical stimulation that leads to asphyxia or death in area A2, thereby preventing the introduction of foreign fish and shellfish into the farm. This will prevent intrusion.

Next, FIG. 4 showing another embodiment will be explained.

In the same figure, the same symbols as in FIGS. 1 to 3 indicate the same things, and the difference from FIGS. A plurality of third rod-shaped bodies 3c are arranged at approximately equal intervals, and a plurality of fourth conductive electrodes 5d similar to the second conductive electrode 5b are respectively connected to the upper side of the third rod-shaped bodies 3c to electrically conduct each other. to form the fourth electrode row 4d, and the fourth electrode row 4 in the sea.
A plurality of fourth rods similar to the first rod-shaped body 3a are placed outside of d.
The rod-shaped bodies 3d are arranged at approximately equal intervals, and the fourth rod-shaped body 3
A plurality of fifth conductive electrodes 5e similar to the first conductive electrode 5a are respectively connected to the upper side of d and electrically connected to each other to form a fifth electrode row 4e, and the fifth electrode row 4e is grounded, The DC voltage is applied between the fourth and fifth electrode rows 4d and 4e by the power source 6a, and since the fourth and fifth electrode rows 4d and 4e are provided, there is also a voltage applied to the outside of the third electrode row 4c. An electric screen similar to the electric screen shown in FIG. 3 is formed on the target, and foreign fish and shellfish that invade the electric screen can be protected from damage caused by electrical stimulation.

As shown in FIG. 5, a plurality of sixth conductive electrodes 5f similar to the third conductive electrode 5c are arranged at approximately equal intervals on the outside of the third electrode row 4c, and are electrically connected to each other. A sixth electrode row 4f is formed, a DC voltage is applied between the sixth and first electrode rows 4f and 4a by another electric screen generation power source 6c, and a third electrode row 4f is formed.
A blocking area for foreign fish and shellfish may be formed outside the electrode array 4c.

Alternatively, an AC voltage or a pulse voltage may be applied by each power source 6a to 6c.

Further, the structure of each conductive electrode is not limited to that described above, and it goes without saying that the number of electrode rows may be two rows or six or more rows.

〔Effect of the invention〕

As described above, according to the electric screen generator of the present invention, since the depth of the lower end of each conductive electrode is made different for each electrode row, it is possible to form a region with low electric field strength near the seabed. , it becomes possible to recover and resuscitate paralyzed fish and shellfish by electrical stimulation in areas with low electric field strength,
It can protect fish and shellfish from damage caused by electrical stimulation, and the effect is very large.

[Brief explanation of drawings]

1 to 5 show an embodiment of the electric screen generator of the present invention, and FIGS. 1 to 3 show one embodiment, FIG. 1 is a perspective view, and FIG. 2 is an equipotential line diagram. A distribution diagram, FIG. 3 is an operation explanatory diagram, and FIGS. 4 and 5 are schematic configuration diagrams of other embodiments, respectively.
FIG. 6 is a schematic diagram of an electric screen generator for comparison with the present invention. 4a to 4f... electrode row, 5a to 5f... conductive electrode, 6a to 6c... power supply.

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 each of the conductive electrodes of each of the electrode rows electrically connected to each other. a connecting body;
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 of the electrode rows is different, and the depth of the lower end of each of the conductive electrodes is made different for each of the electrode rows. An electric screen generator characterized by: