JPH0442799B2 - - 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. 5, 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 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 depth of the water, are placed in the seawater. The conductive electrodes 1b are electrically connected to each other to form the other electrode row 2b, and the electrode row 2b is arranged at a certain distance from the electrode example 2a. A DC voltage, for example, is applied between the two electrode rows 2a and 2b by a power source for electric screen generation (not shown) so that, for example, one electrode row 2a has a high potential and the other electrode row 2b has a low potential. However, an electric screen is generated between both electrode rows 2a and 2b.

Note that the one-dot chain line in FIG. 5 indicates both electrode arrays 2a,
2b shows equipotential lines obtained by connecting equipotential points in a vertical cross section perpendicular to 2b.

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 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. Shellfish are trapped, and 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. 5 mentioned 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.

Furthermore, since each of the conductive electrodes 1a and 1b is longer than the water depth, there is a problem that the current-carrying portion is large and the power consumption is large.

Therefore, in this invention, even if fish and shellfish are paralyzed by electrical stimulation from an electric screen, they can automatically recover and resuscitate, thereby protecting fish and shellfish from damage caused by electrical stimulation and reducing power consumption. The technical challenge is to achieve this goal.

[Means for solving problems]

This invention has been made with the above points in mind, and includes a plurality of electrode rows each formed by a plurality of conductive electrodes arranged at approximately equal intervals under the sea and arranged parallel to each other. , a connection body that electrically connects each of the conductive electrodes of each of the electrode rows 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 of the electrode rows is different. The electric screen generating device is characterized in that each of the conductive electrodes is made shorter than the depth of water, and 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.

Furthermore, since each conductive electrode is shorter than the water depth, the current-carrying portion is smaller than in the case of FIG. 5 described above, and power consumption can be significantly reduced.

〔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, 1 indicates a plurality of vertically extending first ridges that are longer than the depth of the water and are arranged at approximately equal intervals in seawater.
It is a rod-shaped body, and each rod-shaped body 1 has an insulating part 1a in the lower half.
and a conductive electrode 1b in the upper half, and each conductive electrode 1b in the upper half is set shorter than the water depth.

Reference numeral 2 denotes a plurality of vertical second rod-like bodies that are longer than the water depth and are disposed in seawater at the same intervals as the first rod-like bodies 1, and each rod-like body 2 has an insulating part 2a at a lower end and an upper end. , 2b and a central conductive electrode 2c, each of the central conductive electrodes 2c is set to be shorter than the water depth and approximately the same length as the underwater portion of the conductive electrode 1b.

Reference numeral 3 denotes a plurality of vertical third rod-like bodies that are longer than the depth of the water and are disposed in seawater at the same intervals as the first rod-like bodies 1, and each rod-like body 3 has a conductive electrode 3a at the lower end and a conductive electrode 3a at the lower end. The conductive electrodes 3a at the lower end are set to have the same length as the conductive electrode 2c, and the conductive electrodes 1b, 2c, 3a are electrically connected to each other to form the first to third conductive electrodes 3a. Electrode rows 4a-4
The electrode rows 4a to 4c are arranged in parallel to each other, and the depths of the lower ends of the conductive electrodes 1b, 2c, and 3a of each electrode row 4a to 4c are gradually increased.

Note that 5a and 5b 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. The spacing between the equipotential lines on the side is wide, indicating that the electric field strength is low, and the spacing between the equipotential lines is narrow and almost uniform in the area beyond that, that is, between each electrode row 4a to 4c. , indicating that the electric field strength is high and almost constant.

That is, in a vertical cross section perpendicular to each electrode row 4a to 4c, the upper and lower ends of each conductive electrode 1b, 2c, and 3a are connected with a straight line, as shown by the dashed-dotted line in FIG. Assuming parallel straight lines passing through the upper and lower ends of the second rod-shaped body 2, respectively, as the two-dot chain lines in the figure, the areas A1 and A2 inside the two-dot chain lines in the figure have the highest electric field strength. is high, and the electric field strength in areas B1, B2, B3, and B4 between the one-dot chain line and the two-dot chain line in the same figure is the area A1,
Area lower than A2 and outside the two-dot chain line in the same figure
The electric field strength of C1 and C2 becomes even lower.

By the way, if a marine farm is formed by arranging the electrode arrays 4a to 4c inside the first electrode array 4a so as to surround a specific range, 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, and then moves to the seabed, that is, area B3 and C2 where the electric field strength is low. The animal eventually recovers from its paralyzed state, revives itself, and swims back to the ranch on its own.

Additionally, when farmed fish enter area B3 in Figure 3 from the middle part between the sea surface and the seabed, they receive a relatively mild electrical stimulus 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 B3, B4, and C2 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 C2 and then B4.
Fish and shellfish that invade the area will take repellent behavior by mild electrical stimulation.

Therefore, the farmed fish and shellfish within the farm can be prevented from escaping outside the farm, and at the same time, the farmed fish and shellfish can be protected from damage caused by electrical stimulation.

At this time, since each of the conductive electrodes 1b, 2c, and 3a is shorter than the water depth, the current-carrying portion becomes smaller than in the case shown in FIG. 5 described above, and power consumption can be significantly reduced.

On the other hand, for non-native fish grown outside of farms, they are usually larger and longer than farmed fish, so even if the electric field strength is the same, the longer the body, the larger the current flowing through the body, and the electrical stimulation they receive. is strong, and if the electric field strength in areas A1 and A2 is set to a level that paralyzes small fish, large foreign fish will
The strong electrical stimulation in A2 will cause asphyxia or lethality, preventing foreign fish and shellfish from entering the farm, and the electric field strength in area A2 will be reduced to A1.
If we set it higher, we can more effectively prevent foreign fish and shellfish from entering the farm.

In addition, as shown in FIG. 4, for each third rod-shaped body 3, rod-shaped bodies 1' and 2' having the same structure as the first and second rod-shaped bodies 1 and 2, respectively, are attached to each of the first rod-shaped bodies 1 and 2. each second
The conductive electrodes 1b' and 2c' which are arranged symmetrically with the rod-shaped body 2 and constitute each of the rod-shaped bodies 1' and 2' are electrically connected to each other to form fifth and fourth electrode rows 4e and 4d. Then, the fifth electrode row 4e becomes the ground potential, and the fourth electrode row 4e becomes the ground potential.
A voltage may be applied by the power source 5a so that the electrode row 4d has the same potential as the second electrode row 4b.

Alternatively, alternating current voltage or pulse voltage may be applied by both power supplies 5a and 5b.

Furthermore, 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, four, or six or more rows.

〔Effect of the invention〕

As described above, according to the electric screen generator of the present invention, each conductive electrode is made shorter than the water depth, and the depth of the lower end of each conductive electrode is made different for each electrode row, so that the current-carrying part is shortened and consumed. In addition to significantly reducing power consumption, it is also possible to create a region with low electric field strength near the seabed, making it possible to recover and resuscitate paralyzed fish and shellfish through electrical stimulation in the region with low electric field strength. , it can protect fish and shellfish from damage caused by electrical stimulation, and its effects are very large.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the electric screen generator of the present invention, Figures 1 to 3 show one embodiment, Figure 1 is a perspective view, and Figure 2 is an equipotential line diagram. FIG. 3 is a diagram for explaining the operation, FIG. 4 is a schematic diagram of another embodiment, and FIG. 5 is a schematic diagram of an electric screen generator to be compared with the present invention. 1b, 2c, 3a, 1b', 2c'...conductive electrodes,
4a to 4e...electrode array, 5a, 5b...power supply.

Claims (1)

[Claims] 1 A connection in which a plurality of electrode rows are formed by arranging a plurality of conductive electrodes at approximately equal intervals in the sea and are arranged parallel to each other, and the conductive electrodes of each of the electrode rows are electrically connected 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 of the electrode rows is different, wherein each of the conductive electrodes is made shorter than the water depth, and a lower end of each of the conductive electrodes is provided. An electric screen generator characterized in that the depth of the electrodes is different for each of the electrode rows.