JPH0551160B2 - - 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 also 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 Nets may be washed away due to water damage, 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 applicant has proposed the following electric screen generator.

That is, a plurality of vertically extending rod-shaped conductive electrodes are arranged in seawater at approximately equal intervals, and each conductive electrode is electrically connected to each other to form a first electrode row. The vertical bar-shaped conductive electrodes are arranged at approximately equal intervals with the same pitch as the first electrode row, and the conductive electrodes in each row are electrically connected to each other to form the second to Nth conductive electrodes. electrode rows are formed, each electrode row is arranged in parallel, and a DC voltage, for example, is applied between each electrode row using a power source for generating an electric screen (not shown) so that the potential of each electrode row is different. , which generates an electric screen between each electrode row.

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 electric shock reaction occurs and it becomes impossible to swim through the electric screen, and each electrode row is arranged so that a specific area is surrounded by the electric screen,
Fish and shellfish will be confined within the area surrounded by the electric screen, and the swimming of fish and shellfish will be reliably blocked without using nets as in the past, and the tide level,
It is not affected by ocean conditions such as tides and water depth, or weather conditions such as typhoons, making it suitable for large-scale aquaculture such as on marine farms.

By the way, when we investigated the relationship between the electric field strength E [V/cm] and current application time t [sec] of the electric screen formed in seawater and the electric shock reaction of fish and shellfish, we found that one point in Figure 6 The electric shock reaction occurs in the area to the right of the chain line, that is, the shaded area in the same figure, and the larger the electric field strength E and the longer the current application time t, the stronger the electric shock reaction such as paralysis, asphyxia, and even death. A relatively strong electric shock reaction starts to occur near the boundary line indicated by the dashed-dotted line in the figure, and this boundary line is defined by the product E・t of the electric field strength E and the energization time t, indicated by the dashed line in the figure. can be approximated to a curve of 0.1 [V・sec/cm], so E・t<0.1
If energization is repeated within the range of [V sec/cm],
This means that fish and shellfish will not show strong electric shock reactions such as paralysis.

[Problem that the invention seeks to solve]

However, as mentioned above, when using an electric screen to block the swimming of fish and shellfish, the electric field strength is kept constant at a relatively high value, so fish that have entered the electric screen are suddenly subjected to strong electrical stimulation. The fish is electrocuted, its senses and even its body are paralyzed, and it is unable to escape from the electric screen.
This eventually leads to death, and there is a problem in that cultured fish and shellfish suffer damage such as asphyxia and death due to the electrical stimulation in the electric screen.

Therefore, in this invention, when fish and shellfish enter an electric screen and receive electrical stimulation, the fish and shellfish can take repellent behavior before becoming paralyzed, and the electrical stimulation causes the fish and shellfish to suffer asphyxia or death. The technical challenge is to prevent this from happening.

[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; A connecting 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 the electrode rows so that the potentials of the electrode rows are different. The electric screen generating apparatus is characterized in that the electric screen generating apparatus is provided with voltage adjusting means for repeatedly increasing and decreasing the voltage applied by the power source.

[Effect]

Therefore, according to the present invention, a voltage is applied between each row of electrodes arranged in seawater by a power source for generating an electric screen, and the voltage applied by the power source is repeatedly increased and decreased by the voltage adjusting means, so that each electrode The electric field strength of the electric screen formed between the rows changes repeatedly from high to low, and even if fish and shellfish that have entered the electric screen receive strong electrical stimulation due to the high electric field strength, the electric field strength will not change. By gradually decreasing the electric stimulation received by the fish and shellfish, the electrical stimulation received by the fish and shellfish becomes gradually lighter, and the fish and shellfish are able to take sufficient repellent behavior to the point of paralysis. This prevents asphyxia, death, etc. from occurring due to electrical stimulation as in the past.

〔Example〕

Next, the present invention will be described in the first embodiment shown in its embodiment.
This will be explained in detail with reference to FIGS.

(First Example) First, FIG. 1 and FIG. 2 showing the first example will be described.

In FIG. 1, 1a is a first electrode array formed by disposing a plurality of vertically extending rod-shaped conductive electrodes 2a in seawater at approximately equal intervals, and 1b is a vertically extending rod-shaped conductive electrode 2b in seawater. are the second electrode rows formed at substantially equal intervals with the same spacing as the first electrode row 1a, and are arranged parallel to the first electrode row 1a, and are connected by connecting bodies (not shown). , each conductive electrode 2a and 2b has both electrode rows 1a,
1b are electrically connected.

3 is an AC power source for generating an electric screen; 4 is a voltage adjusting means consisting of a variable resistor whose one end and the other end are connected to both ends of the power source 3; the first electrode row 1a is connected to a sliding terminal; , second on the other end
Electrode array 1b is connected.

At this time, both electrode rows 1a and 1b are arranged so as to surround a specific culture area, and the voltage applied between both electrode rows 1a and 1b is controlled by the adjusting means 4.
Repeatedly increase and decrease every 0.5 seconds, both electrode rows 1a,
The electric field strength E between 1b changes from 0 to 0.1 [V/
cm], so that the product E・t of the electric field strength E and the energization time t is 0.1 [V・sec/
cm], and the voltage is adjusted so that the relationship between the energization time t of the electric screen between both electrode rows 1a and 1b and the electric field strength E changes at a cycle of 1 second as shown in FIG.

Therefore, even if a cultured fish that has entered the electric screen between both electrode rows 1a and 1b receives strong electrical stimulation due to the electric field strength near the peak point of the current conduction characteristics shown in Figure 2, the electric field strength gradually decreases. As the electric stimulation is lowered, the electrical stimulation received by the cultured fish gradually becomes lighter, and the cultured fish can escape from the electric screen to the culture area by taking sufficient repellent behavior before becoming paralyzed.

In addition, if a foreign fish invades the electric screen between the electrode arrays 1a and 1b, the foreign fish is larger and has a longer body length than the cultured fish, so the electric field strength will be stronger than that of the small cultured fish even if the electric field strength is the same. Because of the electrical stimulation, foreign enemy fish that have entered the electric screen are paralyzed and prevented from entering the culture area inside.

(Second Example) Next, as a second example, in the configuration shown in FIG.
Increase or decrease the applied voltage between electrodes 1a and 1b.
The electric field strength E between them increases from 0 to 0.1 [V/cm] in 1 second and then instantly decreases to 0, and the electric field strength E is By adjusting the voltage so that the relationship changes at a period of 1 second as shown in FIG. 3, the same effect as in the first embodiment can be obtained.

Note that the product E・t of the electric field strength E and the energization time t is
As in the first embodiment, the voltage is set not to exceed 0.1 [V·sec/cm].

(Third Embodiment) Furthermore, FIGS. 4 and 5 show the third embodiment.
The diagram will be explained.

In FIG. 4, the same symbols as in FIG. 1 indicate the same or corresponding things, and the difference from FIG. , the third electrode row 6 is formed by arranging the conductive electrodes 5 at substantially equal intervals with the same spacing as in the case of the first electrode row 1a, and the conductive electrodes 5 are electrically connected by a connector (not shown) to form the third electrode row 1a. 6 are arranged parallel to the first electrode row 1a, and the first and third electrode rows 1a,
6 is narrower than the distance between the first and second electrode rows 1a and 1b, and the third electrode row 6 is made smaller than the distance between the first and second electrode rows 1a and 1b.
Similarly, this point is connected to the other end of the adjusting means 4.

At this time, the electric field strength between the narrowly spaced first and third electrode arrays 1a and 6 is increased and decreased between 0 and 0.1 [V/cm] every 0.5 seconds by the adjusting means 4, The relationship between the energization time t of the electric screen between the first and third electrode rows 1a and 6 and the electric field strength E is as follows:
When the voltage is adjusted so that the voltage changes at a period of 1 second as shown by the solid line in FIG. It is lower than the peak value of the electric field strength E between the rows 1a and 6, and the first and second electrode examples 1a and 1b
The relationship between the energization time t of the electric screen and the electric field strength E is as shown by the dashed line in FIG.

Therefore, by arranging each electrode row 1a, 1b, 6 with the second electrode row 1b outside so as to surround a specific culture area, the first, third electrode rows 1a,
By using the electric screen between 6 and 6, it is possible to take sufficient repellent action until the cultured fish that invade the electric screen become paralyzed, in the same manner as in the first embodiment, and the first and second electrodes Column 1a, 1
An electric screen with a low electric field strength between b and 12b allows enemy fish that invade the electric screen to take sufficient repellent action to the point of paralysis, just as in the case of farmed fish, and both the farmed fish and the enemy fish are protected. It is possible to prevent asphyxia or death from occurring due to the electrical stimulation of the electric screen.

Note that it goes without saying that four or more electrode rows may be provided.

Further, the power source for generating the electric screen may be configured by a DC power source.

Furthermore, the voltage adjusting means is not limited to those described above.

〔Effect of the invention〕

As described above, according to the electric screen generator of the present invention, even if fish and shellfish invade the electric screen, it is possible to take sufficient repellent action to prevent the fish and shellfish from becoming paralyzed. It is possible to prevent various types of fish and shellfish that have entered the electric screen from suffering asphyxia or death due to electrical stimulation, which is extremely effective.

In addition, the voltage adjustment means repeatedly increases and decreases the voltage applied between each electrode row by the power supply for generating the electric screen, significantly reducing power consumption compared to the conventional case where a constant voltage is continuously applied. This makes it possible to provide an extremely economical electric screen generator.

[Brief explanation of drawings]

1 to 5 show embodiments of the electric screen generator of the present invention, FIG. 1 is a perspective view of the first embodiment, and FIGS. 2 and 3 show the first embodiment and the second embodiment, respectively. FIG. 4 is a perspective view of the third embodiment. FIG. 5 is a diagram of the relationship between current application time and electric field strength in the third embodiment. FIG. 3 is a diagram showing the relationship between current application time and electric field strength when an electric shock reaction occurs. 1a, 1b, 6...first, second, third electrode rows,
2a, 2b, 5... Conductive electrode, 3... AC power supply,
4...Voltage adjustment means.

Claims (1)

[Scope of Claims] 1. A plurality of electrode rows each formed in seawater with a plurality of conductive electrodes arranged at approximately equal intervals and arranged in parallel to each other, and each of the conductive electrodes of each of the electrode rows. A connecting body electrically connected to each other,
An electric screen generating device comprising: 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; a voltage adjusting means for repeatedly increasing and decreasing the voltage applied by the power source; An electric screen generator characterized by being provided with.