JPH0577368B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fish and shellfish swimming blocking device that blocks the swimming of fish and shellfish, such as seaweed and algae, into and out of a farm.

[Conventional technology]

In general, as a method to prevent fish and shellfish such as seafood and algae from entering and exiting the farm, instead of the conventional rope, the seawater around the farm S is used as shown in Figure 10. Electrodes 1 are arranged at equal intervals inside,
Applying different potentials to adjacent electrodes 1 depending on the power source,
It has been considered to form an electric field around the farm S to block the swimming of fish and shellfish.

At this time, in order to arrange each electrode 1 at equal intervals,
The shape of the aquaculture farm S is a square, and at positions corresponding to the corners of this square, the inner sides of adjacent electrodes 1 are in a state of being very close to each other.

[Problem to be solved by the invention]

In the conventional technology, if the electric field strength that has the effect of blocking the swimming of fish and shellfish is defined as the effective electric field strength, the effective electric field strength region expands inward from the line connecting the inner ends of each electrode 1, and each electrode The spread of the effective electric field strength region outward from the line connecting the outer ends of 1 is almost the same, and the effective electric field strength region for blocking the swimming of foreign fish and shellfish outside the farm S is narrow;
There is a slight lack of certainty in the swimming blocking effect on foreign fish and shellfish.

By the way, in order to enhance the effect of blocking the swimming of foreign fish and shellfish, the voltage applied to each electrode 1 is increased to increase the maximum value of the electric field strength, and the effective electric field strength area outside the line connecting the outer ends of each electrode 1 is increased. When the spread is increased, the spread inward from the line connecting the inner ends of each electrode 1 also becomes larger, making it easier for farmed fish and shellfish to receive electrical stimulation from the electric field, and increasing the influence of the electric field on the farmed fish and shellfish. There is a problem.

On the other hand, for farmed fish and shellfish in the farm S, it is better to have as little influence as possible from the formation of the electric field, and for this purpose, it is necessary to reduce the effective electric field strength region inward from the line connecting the inner ends of each electrode 1. It is better to reduce the spread and make the area where the farmed seafood does not receive electrical stimulation as wide as possible, by lowering the voltage applied to each electrode 1 to lower the maximum electric field extreme, and by connecting the inner edges of each electrode 1. If the spread of the effective electric field strength region is made smaller inward, the spread outward from the line connecting the outer ends of each electrode 1 will also become smaller, causing the inconvenience that the swimming blocking effect on predator fish and shellfish will be weakened. .

Therefore, the present invention has been made with the above points in mind,
The purpose is to reduce the influence of electric fields on farmed fish and shellfish by minimizing the area where cultured fish and shellfish are exposed to electrical stimulation within the farm, without weakening the swimming-blocking effect on fish and shellfish outside the farm. .

[Means to solve the problem]

In order to achieve the above purpose, a plurality of electrodes are arranged in the seawater around the fish farm, and a power source applies different potentials to the adjacent electrodes, and a system is installed around the fish farm to block the swimming of fish and shellfish. In a fish and shellfish swimming blocking device that generates an electric field, the present invention is characterized in that the distance between adjacent electrodes is larger on the outside than on the inside.

[Effect]

Because of the above configuration, when different potentials are applied to adjacent electrodes, the spread of the effective electric field strength region outward from the line connecting the outer ends of each electrode is equal to the line connecting the inner ends of each electrode. This prevents the swimming-blocking effect on fish and shellfish outside the farm from fading, and furthermore, the area where farmed fish and shellfish inside the farm receive electrical stimulation becomes smaller, making it easier for farmed fish and shellfish to grow. The influence of the electric field on the

〔Example〕

Examples will be described with reference to FIGS. 1 to 9.

(Principle) Prior to explaining the embodiments, the principle of the present invention will be explained using FIGS. 7 to 9.

Now, as shown in FIG. 7, two flat electrodes 2a and 2b with a width L are arranged in parallel in seawater with a distance D apart, and a voltage Vp is applied to both electrodes 2a and 2b by a power source 3. is applied to form an electric field between both electrodes 2a and 2b. Here, the other electrode 2b was set at ground potential.

Then, with D/L as a parameter, the theoretical electric field strength E (=Vp/D) is maintained at 1 [V/cm],
X- in Figure 7 when changing the parameter D/L
The distribution of electric field strength at each point on the X' line and the Y-Y' line is as shown in FIGS. 8 and 9, respectively. However, the X-X' line represents both electrodes 2a and 2b when viewed from above.
The Y-Y' line corresponds to the extension line of one electrode 2a.

Note that the solid lines in FIGS. 8 and 9 indicate D/L=2,
The broken line is D/L=1.4, the dashed line is D/L=1.0, 2
The dashed dotted lines indicate data when D/L=0.4.

In addition, in FIGS. 8 and 9, the horizontal axis is based on a line connecting the front ends of both electrodes 2a and 2b as shown by the broken line in FIG. The distance to the point on the X-X' line and the Y-Y' line is shown.

From FIG. 8, which shows the distribution of electric field strength on the X-X' line, the larger the parameter D/L is, the greater the degree of leakage of the electric field is, for example, in front of the line connecting the front ends of both electrodes 2a and 2b. It can be seen that if the electrode width L is constant, the larger the electrode spacing D becomes, the wider the effective electric field strength region becomes.

On the other hand, between the electrodes 2a and 2b behind the line connecting the front ends of the electrodes 2a and 2b, from FIG. 8, the larger the parameter D/L, the smaller the electric field strength.

Next, from FIG. 9, which shows the distribution of electric field strength on the Y-Y' line, it can be seen that the smaller the parameter D/L, the smaller the degree of leakage of the electric field, and as mentioned above, the electrode width L
Assuming that is constant, the smaller the electrode spacing D, the more
It can be seen that the effective electric field strength region becomes narrower.

Note that the area behind the line connecting the front ends of both electrodes 2a and 2b corresponds to a point on electrode 2a, so the electric field strength becomes zero as shown in FIG.

Therefore, in order to widen the effective electric field strength region to the outside between both electrodes 2a and 2b, it is sufficient to widen the interval between both electrodes 2a and 2b, and conversely, to narrow the effective electric field strength region, both electrodes The distance between 2a and 2b may be narrowed, and an embodiment based on this principle will be described below.

Example 1 First, FIGS. 1 to 4 showing Example 1 will be explained.

In FIG. 1 showing a schematic configuration, reference numeral 4 indicates electrodes arranged radially at fixed angles in the seawater surrounding the circular aquaculture farm S, reference numeral 5a indicates a connection cable connecting every other electrode 4, and 5b 6 is a connection cable connecting each of the remaining electrodes 4, and 6 is a power source, both output terminals of which are connected to both cables 5a and 5b, and apply different potentials to adjacent electrodes 4.

At this time, since each electrode 4 was arranged radially,
The distance between adjacent electrodes 4 is larger than the inner side D1.
D2 will be larger.

Therefore, the electric field distribution around the electrode 4 arranged in this way is as shown in FIG.
The dashed dotted lines are equal electric field strength lines, 1.0, 0.8, 0.5,
Each value of 0.3 and 0.2 indicates the potential, and from the same figure, from the inner end and outer end of each electrode 4, respectively,
For example, the distance to the equal electric field strength line with a potential of 0.2 is greater on the outside. In addition, in Fig. 2, the electric field strength at the center between adjacent electrodes 4 is "1.0".
This is the electric field distribution when it is set as follows.

Furthermore, the electric field strength distribution on the Z-Z' line in FIG. 2, which corresponds to the midline when two adjacent electrodes 4 are viewed in plan, is as shown in FIG. As can be seen from the figure, the spread of the electric field on the open sea side is larger than that on the farm S side. For example, if the threshold value of the effective electric field strength is set to "0.2", the electric field strength increases.
When illustrating the effective electric field strength region of 0.2 or more, the fourth
It is within the shaded range in the figure, and it is clear from FIG. 4 that the effective electric field strength region on the open sea side is wider than on the fish farm S side.

In this way, according to the first embodiment, since the flat electrodes 4 are arranged radially, the spread of the effective electric field strength region outward from the line connecting the outer ends of each electrode 4 is It can be made larger than the spread towards the fish farm S from the connecting line, and the fish farm S
It is possible to prevent the swimming blocking effect on the fish and shellfish outside the farm S from fading, and to minimize the area where the cultured fish and shellfish in the farm S receive electrical stimulation, thereby reducing the influence of the electric field on the cultured fish and shellfish. Compared to the past, it is possible to more reliably prevent foreign fish and shellfish from entering the farm S, and at the same time, it is possible to effectively protect farmed fish and shellfish from electrical stimulation.

Example 2 Next, FIGS. 5 and 6 showing Example 2 will be described.

In FIG. 5 showing the configuration, 7 is a plurality of electrodes, each of which is a plurality of electrode rods 8 arranged in a V-shape at equal intervals in seawater and electrically connected to each other.
Each electrode 7 is connected to the farm S at a predetermined interval so that the open side of the V-shape of the electrode 7 is located on the farm S side.
It is located in the seawater surrounding the. Reference numeral 9 denotes a power source, which applies different potentials to adjacent electrodes 7.

At this time, place the V-shaped electrode 7 on the farm S side.
Since the electrodes 7 are arranged so that the open side of the letter is located, the distance between adjacent electrodes 7 is larger on the outside than on the inside.

Note that the dashed-dotted lines in FIG. 5 indicate equal electric field strength lines.

In such an electrode arrangement, the fifth point corresponds to the midline when two adjacent electrodes 7 are viewed from above
The distribution of the electric field strength on line A-A' in the figure is as shown by the solid line in FIG. 6, and it can be seen that the electric field spreads wider on the open sea side than on the fish farm S side.

Also, B- corresponding to the midline of one electrode 7
The distribution of electric field strength on line B' is as shown by the dashed-dotted line in Figure 6, and the electric field strength near electrode 7 on the open sea side is very large and gradually decreases as it moves away from electrode 7. , the electric field strength is almost zero inside the electrode 7.

Therefore, according to the second embodiment, effects equivalent to those of the first embodiment can be obtained.

Furthermore, in the second embodiment, the shape of the aquaculture farm S is not limited to a circular shape as in the first embodiment, but can also be applied to a quadrangular shape, and the range of application can be expanded.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

Multiple electrodes were placed in the seawater around the farm so that the distance between adjacent electrodes was larger on the outside than on the inside, and different potentials were given to the adjacent electrodes depending on the power supply, which enabled the fish and seafood to be When the effective electrode strength is the electric field strength that can block the swimming of
The spread of the effective electrode strength region outward from the line connecting the outer ends of each electrode can be made larger than the spread toward the farm side from the line connecting the inner ends of each electrode, and fish and shellfish outside the farm can be It is possible to prevent the swimming blocking effect from fading away, and the area where the cultured fish and shellfish in the farm receive electrical stimulation can be extremely small, reducing the influence of the electric field on the cultured fish and shellfish. It is possible to more reliably prevent fish and shellfish from entering a farm, and at the same time, it is possible to effectively protect farmed fish and shellfish from electrical stimulation.

[Brief explanation of the drawing]

Figures 1 to 9 show examples of the fish and shellfish swimming blocking device of the present invention, Figures 1 to 4 show Example 1, Figure 1 is a partial plan view, and Figure 2 is a partial plan view. 3 is an electric field distribution diagram, FIG. 3 is an electric field intensity distribution diagram on the Z-Z′ line in FIG. 2, FIG. 4 is a plan view showing the effective electric field strength region, and FIGS. 5 and 6 show Example 2. , 5th
The figure is a partial plan view, and Figure 6 is A- in Figure 5.
The electric field strength distribution diagrams on the A' line and the B-B' line, and FIGS. 7 to 9 are diagrams explaining the principle of the present invention.
The figure is a plan view showing the electrode arrangement, Figures 8 and 9 are electric field strength distribution diagrams on the X-X' line and Y-Y' line in Figure 7, respectively, and Figure 10 is a plan view of the conventional example. be. S... Fish farm, 4, 7... Electrode, 6, 9... Power supply.

Claims (1)

[Scope of Claims] 1. A plurality of electrodes are arranged in seawater around a fish farm, and a power source applies different potentials to adjacent electrodes, thereby creating an electric field around the fish farm for blocking the swimming of fish and shellfish. A swimming-blocking device for fish and shellfish, characterized in that the spacing between the adjacent electrodes is larger on the outside than on the inside.