JPH0573368B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for blocking fish and shellfish from swimming in a prohibited area.

[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 prevents fish and shellfish from escaping and from entering the inside of the cage.

However, in the case of this type of cage system that uses nets, even if the water depth is not too deep, the waves are calm, and tidal changes are small, there is a risk of the nets being damaged by typhoons, being washed away, or being damaged by contact with ships. This is disadvantageous in that it is not possible to reliably and easily block the swimming of fish and shellfish with the net, as it requires a great deal of effort and expense to maintain and maintain the net.

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 applicant has proposed the following method.

In other words, multiple electrode rows are arranged in parallel in seawater to surround a specific sea area, and a voltage is applied to each electrode row to form a region with a predetermined electric field strength between each electrode row. Prevent other species from swimming in restricted areas.

[Problem that the invention seeks to solve]

However, in this case, even if the electric field strength is the same, the electrical stimulation received by the fish and shellfish differs depending on the body length of the fish, and fish and shellfish with long bodies may receive strong electrical stimulation and exhibit reactions such as numbness or paralysis. Even if the electric field is strong, fish and shellfish with a short body length receive only weak electrical stimulation, so they easily swim between the electrode rows and enter or escape from the specific water area. If the electric field strength is such that fish and shellfish receive strong electrical stimulation, longer fish and shellfish will receive even stronger electrical stimulation and die. The problem is that it is very difficult to set a suitable electric field strength.

Therefore, the technical problem of the present invention is to ensure that swimming of fish and shellfish to be blocked can be destroyed.

[Means for solving problems]

This invention has been made with the above-mentioned points in mind. A plurality of electrode rows are arranged in parallel in water, and a voltage is applied to each of the electrode rows to create a predetermined electric field strength between each of the electrode rows. In a method for blocking the swimming of fish and shellfish, which forms a region of V] This is a method for blocking the swimming of fish and shellfish, which is characterized in that the above is achieved.

[Effect]

Therefore, according to the present invention, the electric field strength E [V/cm] and the body length L of the fish and shellfish to be interrupted are used as parameters for determining the electric field strength between each electrode row.
The product E・L with [cm] is introduced, and E・L is 0.05
A region having a voltage of [V] or more is formed between each electrode row,
It has become possible to apply electrical stimulation that causes shock, numbness, and a paralyzing electric shock reaction to commonly farmed seafood such as "madai", "hirame", "kuruma shrimp", "hamachi", and "sardine". , the swimming of these fish and shellfish will definitely be blocked.

〔Example〕

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

In FIG. 1, 1a and 1b are two electrode rows arranged in parallel in seawater, each of which is formed by a plurality of rod-shaped conductive electrodes 2a and 2b arranged at equal intervals, and both electrode rows 1a , 1b are electrically connected by connecting bodies 3a, 3b. Reference numeral 4 denotes a power supply, and the current 4 applies a direct current voltage to both the electrode arrays 1a and 1b, thereby forming an electric screen area with a predetermined electric field strength between the electrode arrays 1a and 1b.

By the way, as a parameter that determines the electric field strength between both electrode rows 1a and 1b, electric field strength E [V/cm]
Introducing the product E·L of the body length L [cm] of the fish and shellfish to be blocked, and determined the optimal value of E·L as follows.

That is, as shown in FIG. 2, two electrodes 6a, 6 are placed parallel to both ends of the container 5 filled with seawater.
A voltage was applied to both electrodes 6a and 6b by a power source 7 for a long period of time, and the reaction of fish and shellfish 8 of various body lengths placed in a container 5 was investigated.

At this time, the fish and shellfish 8 that are commonly farmed are "madai", "hirame", "kuruma shrimp", "hamachi", and "sardine", and the electric field strength E between both electrodes 6a and 6b and these fish and shellfish are selected. Product of 8 and body length L E・L
When we investigated the value at which fish and shellfish 8 showed a reaction, we found that the body length L is shown in Figure 3.
An electric shock reaction occurs on the right side of the curve in the diagram of the relationship between E and electric field strength E, that is, the shaded area in the diagram. The curved boundary line in the figure is where the animal begins to show the slightest electric shock reaction, such as surprise or slight numbness, and this boundary line is defined by the product E・L of electric field strength E and body length L of 0.05 [ V]
It almost approximates the curve of .

Therefore, both electrode rows 1a and 1b shown in FIG.
The product E・L of electric field strength E and body length L is 0.05 [V]
By forming the above-mentioned area in seawater, it is possible to reliably block the swimming of fish and shellfish such as "seaweed", "flounder", "kuruma shrimp", "hamachi", and "sardine". .

Note that it goes without saying that the number of electrode rows may be eight or more.

〔Effect of the invention〕

As described above, according to the method for blocking swimming of fish and shellfish of the present invention, the product of the electric field strength and the body length of the fish and shellfish to be blocked is introduced as a parameter for determining the electric field strength between each electrode row, and the product of the electric field strength and the body length of the fish and shellfish to be blocked is is set to be 0.05 [V] or more, so you may feel surprised or numb when eating seafood.
It becomes possible to apply electrical stimulation that causes an electric shock reaction to the level of paralysis, and it is possible to reliably prevent swimming of seafood.

[Brief explanation of drawings]

The drawing shows 1 of the method for blocking the swimming of fish and shellfish according to the present invention.
An example is shown in which FIG. 1 is a perspective view, FIG. 2 is a sectional view for explaining the operation, and FIG. 3 is a relationship between the body length of seafood and electric field strength. 1a, 1b...electrode array, 4...power supply, 8...seafood.

Claims (1)

[Scope of Claims] 1. A plurality of electrode rows are arranged in parallel in water, a voltage is applied to each of the electrode rows to form a region with a predetermined electric field strength between the electrode rows, and the region allows fish and shellfish to be In a method for blocking the swimming of fish and shellfish in areas where entry of fish and shellfish is prohibited, the product of the electric field strength in the area and the body length of the fish and shellfish to be blocked must be 0.05 [V] or more. Characteristic method of blocking swimming of fish and shellfish.