JP2007105002A - Apparatus for capturing fish of foreign origin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for capturing fishes of foreign origin easily installed irrespective of variation of water level or geological features of the waterside and capturing larvae or fries and even the fishes of the foreign origin which are difficult to capture by conventional techniques. <P>SOLUTION: The apparatus is equipped with frame-like rafts 1 and 2, water plants 4 arranged in a water area divided with the rafts and a laying net 5 laid so as to be liftable in the bottom of the water area. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fish catching apparatus that can catch fish at various growth stages from larvae to adult fish.

Conventional fish, particularly foreign fish, have been collected by means of stationary fishing gear such as stabbed nets and stationary nets and fishing.
Suguro Otani and Akira Kojima “On Carbon Microorganisms and Water Environment” Tokai University Press 2004 “All about Black Bass and Bluegill-Report on Consignment of Foreign Fish Countermeasures”, National Federation of Water Fisheries Cooperative Association, National Federation of Water Fisheries Cooperative Association, 1992

However, according to the above-mentioned conventional technology, it is difficult to install fishing gear itself at a dam with a steep waterside, etc. There were various problems such as failure to function, and the growth stage of exotic fish that could be caught was limited to only young to adult fish, and larvae could not be caught.
In particular, with the conventional method, it was almost impossible to capture individuals at the larva stage due to the specifications of fishing gear and the characteristics of the fishing method itself. Largemouth bass, bluegill, etc., on the other hand, lay many orders of magnitude more eggs than most Japanese freshwater fish, and because of the habit of protecting the eggs and larvae just after hatching for a certain period of time, larvae of native fish species It is known that the initial survival rate is high. This is thought to be a factor in the explosive increase of both species in the domestic water surface. For the extermination of these two species, there was an urgent need to develop a technique that can efficiently capture individuals in the larval stage.

  The present invention has been made in view of the problems of the conventional method, and the purpose of the invention is easy to install regardless of water level fluctuations or waterside topography, and it has been difficult to capture with conventional techniques. An object of the present invention is to provide a fish catching apparatus capable of catching larvae, alien fish such as largemouth bass and bluegill.

  In order to achieve the above object, a fish catching apparatus according to the present invention comprises a frame-shaped squid, aquatic plants arranged in a water area defined by the squid, and a laid layable on the bottom of the water area. With a net.

  According to the present invention, the aquatic plants are preferably made of carbon fibers.

  According to the present invention, preferably, the laying net has a box shape.

  According to the present invention, preferably, the mesh of the laying net is 2.5 to 3.5 mm.

  Moreover, according to this invention, the fish of each growth stage from a juvenile fish to an adult fish can be caught.

  According to the present invention, it is possible to provide a fish collecting device that is not easily affected by fluctuations in water level and topography, and that can be easily installed in a dam lake or the like where the topography is steep and water level fluctuation is large. In addition, according to the present invention, because of the high fish collection effect of carbon fiber artificial aquatic plants, it is possible to efficiently collect exotic fish mainly in the larval and juvenile season, so that the net is collected while moving from place to place. Compared to techniques such as fishing and fishing, it requires less labor to collect. In addition, according to the present invention, larvae and juveniles that cannot be captured with normal fishing gears can be captured, as well as sizes larger than young fish. It also has the effect of preventing killing fish other than the intended purpose.

Hereinafter, an embodiment of the present invention will be described based on one illustrated example.
FIG. 1 is a plan view of an embodiment of a fish collecting apparatus according to the present invention in use, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. is there. In the figure, 1 is a frame formed by assembling a wooden or plastic beam in a square shape, and 2 is a plurality of floats that are preferably formed of foamed polystyrene and attached to the lower part of each side of the frame 1. The squid is configured together with the frame 1. Reference numeral 3 denotes a rope stretched between the opposite sides of the frame 1 preferably at equal intervals, and reference numeral 4 denotes a carbon fiber or the like. The rope 3 is preferably attached to each rope 3 at equal intervals and is suspended from the vicinity of the water surface to a predetermined water depth position. The lowered artificial aquatic plants 5 are laying nets laid under the water area of the aquatic plants 4 by ropes 5a that are removably moored to mooring bodies 6 provided at the four corners of the frame 1.

  The laying net 5 has a box shape having an opening area substantially equal to the area defined by the frame body 1, and the mesh size (size of twice the length of one side of the mesh) is 2.5. ~ 3.5mm is selected. If the mesh size is less than 2.5 mm, the laying net 5 is clogged with suspended solids and dust, and if it exceeds 3.5 mm, the larvae pass through the mesh and cannot be collected. The aquatic plants 4 are arranged on almost the entire water area defined by the frame 1.

  Since the fish collecting apparatus according to the present invention is configured as described above, when installing the apparatus, the net 5 and the aquatic plants 4 are attached to the frame 1 in advance and transported to a desired point and floated by a well-known method. Installation can be completed by mooring. Then, mooring is carried out for a predetermined period, and at the time of collection, the rope 5a moored to the mooring body 6 is unwound, the rope 5a is pulled up using human power or a winch, the pulling net 5 is pulled up to the water surface, The fish gathered around is collected (see Fig. 3).

  Thus, according to the fish catching apparatus of the present invention, it is possible to reliably store the fish in the net 5 from large exotic fish and the like to the larvae, and it is possible to catch various fish efficiently.

Hereinafter, the test results using the fish collection apparatus of the present invention will be described in comparison with the conventional method.
The sampling test was conducted at the Nomura dam, a multi-purpose dam located in the middle of the Yodo River basin in Seiyo City, Ehime Prefecture, in western Shikoku. The dam lake has been maintained in the dam lake, which is a rare dam lake landlock for over 20 years. According to a survey conducted by the applicants in 2003 and 2016, In particular, it has been found that serious damage to sweetfish is caused by largemouth bass and bluegill, especially in spring.

According to a total of four sampling tests conducted from May 30 to June 24, 2005 at the same dam, as shown in Table 1, 2 species, 3 families and 7 species of fish were captured. Of these, 195 were largemouth bass, 763 were bluegill, and the average number of catches per survey was 48.8 largemouth bass and 190.8 bluegill.

On the other hand, the results of collection using a stabbed net, which is a conventional method, performed at the same place at the same time are as shown in Table 2.

  As is apparent from Table 2, in the conventional technique, the average number of individuals collected per time was 22.4 largemouth bass and 7.2 bluegills. The collection efficiency (ratio of the number of individuals per time) is about 2.2 times larger for largemouth bass and about 26.5 times for bluegill than the conventional method. It was. Furthermore, the breakdown of largemouth bass captured according to the present invention is that there are 193 juvenile fish (99%) with a standard length of 12 to 30 mm, two young and adult fish with a standard length of 130 mm or more, and one bluegill has a standard length. The larvae and juvenile fish from 9 mm to 25 mm accounted for 763 individuals (97.9%) and the adult fish 16 individuals. On the other hand, the smallest individuals in the collection experiment using the conventional method are individuals with a standard body length of 120 mm in largemouth bass and a standard body length of 70 mm in bluegill. There wasn't.

  As described above in the experimental examples, according to the apparatus of the present invention, extremely high collection efficiency can be exhibited for largemouth bass and bluegill larvae that have been difficult to efficiently collect.

  As described above, in the embodiment, the squid is configured as a square, but this may be a rectangle or a circle according to the situation of the installation place, or the shape of the laying net may be adapted to the shape of the frame. . Further, the material of squid and aquatic plants is not limited to those of the embodiments, and various modifications and corrections are possible within the scope of the present invention.

It is a top view of one Example of the fish catching apparatus which concerns on this invention in use condition. It is the II-II sectional view taken on the line of FIG. It is sectional drawing which shows the state at the time of laying net pulling up.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Frame 2 Float 3 Rope 4 Aquatic plant 5 Laying net 5a Rope 6 Mooring body

Claims (5)

  A fish catching device comprising a frame-shaped squid, aquatic plants arranged in a water area defined by the squid, and a laying net laid so as to be able to be pulled up at the bottom of the water area.   2. The fish capturing apparatus according to claim 1, wherein the aquatic plants are made of carbon fiber.   The fish catching apparatus according to claim 1 or 2, wherein the laying net has a box shape.   The fish catching apparatus according to any one of claims 1 to 3, wherein the mesh of the laying net is 2.5 to 3.5 mm.   The fish collection apparatus according to any one of claims 1 to 4, which is capable of collecting fish at each growth stage from larvae to adult fish.

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