Tilapia mossambica trapping device based on 17, 20 beta-p sex pheromone and operation method of tilapia mossambica trapping device

Abstract

The invention discloses a tilapia mossambica trapping device based on 17, 20 beta-p sex pheromone, which comprises a ground cage main body, the size of a frame of the ground cage main body is 50 * 50cm, the length of the ground cage main body is 6m, the frame of the ground cage main body is made of corrosion-resistant stainless steel wires, the periphery of the frame is covered with a net surface, the net surface is made of nylon materials, a fish inlet of the ground cage main body is funnel-shaped, and the fish outlet of the ground cage main body is communicated with the ground cage main body. The fish inlet is enlarged, a plastic bottle is hung in the ground cage body, and the plastic bottle is used for containing fish luring liquid. The operation method of the trapping device comprises the following steps: selecting a proper ground cage; preparing a pheromone solution; selecting a trapping point; and placing a trapping ground cage. According to the method, the 17, 20 beta-P-containing solution coarsely extracted from tilapia mossambica body fluid is adopted for pheromone trapping, and the method is easy and convenient to operate, low in cost, efficient in fish collection and environment-friendly, can reduce interference to an ecological system while meeting the fishing requirement, and has high environment-friendly and sustainable value.

Description

Technical Field

[0001] The present invention relates to the technical field of marine fishing, and specifically relates to a trapping device for Tilapia zillii based on 17,20β-p pheromone and its operation method. Background Art

[0002] Tilapia zillii, also known as the red-bellied tilapia, has the most prominent morphological characteristics: the pharyngeal abdomen is red, there is a black spot behind the dorsal fin, and there are 6 - 8 longitudinal stripes on the body side. Due to its strong environmental adaptability and high reproductive capacity, it has established populations in the water bodies of some areas, affecting the survival of local species and ecological balance.

[0003] Traditional fishing and chemical poisoning have disadvantages such as low trapping efficiency, low fishing specificity, or secondary pollution to the environment. Since fish can communicate using various signals (vision, sound, electric fields, and chemicals), in recent years, the technology of using pheromones to regulate fish aggregation behavior has gradually received attention. 17,20β-dihydroxyprogesterone (17,20β-P) is the main oocyte maturation-inducing hormone in teleost fish and is closely related to reproductive activities such as ovulation. During the breeding period of fish, 17,20β-P will exist in high concentrations in body fluids such as blood and urine. Some studies have shown that the sex hormones in the urine of male tilapia can promote female tilapia to release 17,20β-P. [i] As a key pheromone, 17,20β-p has been proven to have a significant effect in inducing fish reproduction and aggregation phenomena. The present invention combines the 17,20β-p pheromone crudely extracted from the urine of Tilapia zillii with the cage fishing technology, and is expected to achieve precise trapping and effective control of the invasive population of Tilapia zillii. Summary of the Invention

[0004] The purpose of the present invention is to provide a trapping device for Tilapia zillii based on 17,20β-p pheromone and its operation method, so as to efficiently and environmentally friendly trap the Tilapia zillii population in the breeding period, thereby improving the water ecological environment.

[0005] The present invention is achieved through the following technical solutions:

[0006] A trapping device for Tilapia zillii based on 17,20β-p pheromone, including a cage main body, the frame size of the cage main body is 50*50 cm, the length of the cage main body is 6 m, the frame of the cage main body is made of corrosion-resistant stainless steel wire, a net surface is covered around the frame, the net surface is made of nylon material, the fish inlet of the cage main body is in a funnel shape, and this fish inlet is enlarged. A plastic bottle is hung inside the cage main body, and this plastic bottle is used to place fish attractant liquid.

[0007] As a preferred embodiment, the mesh size of the net surface is 5 mm.

[0008] As a preferred embodiment, a flexible plastic sheet is added to the end of the fish inlet to prevent the captured male and female fish of larger sizes from escaping.

[0009] As a preferred embodiment, openings are provided on the bottle body of the plastic bottle in the ridge main body to facilitate the diffusion of pheromones in water.

[0010] An operation method of a tilapia zillii trapping device based on 17,20β-p pheromone specifically includes the following operation steps:

[0011] (1) Select a suitable fishing net.

[0012] (2) Prepare the pheromone solution, including urine collection, crude extraction, filtration, and fish-attracting liquid preparation.

[0013] (3) Select a trapping point: Select a gentle slope with a water depth of 1.5 - 3 meters, relatively clear water, slow water flow, a water temperature of 24 - 30°C, and a natural habitat with aquatic vegetation or stones as the trapping point.

[0014] (4) Place the trapping fishing net:

[0015] Place 1 fishing net at each trapping point. 3 - 5 trapping points can be set simultaneously to form a fish-attracting zone. The distance between each trapping point is 10 - 15 meters to facilitate judging the movement trend of the fish school.

[0016] As a preferred embodiment, the urine collection in step (2):

[0017] Select sexually mature female tilapia zillii with a body length of 10 cm or more (there are 3 holes in front of the anal fin of the abdomen, including the anus, genital pore, and urinary pore; male tilapia zillii have 2 holes, including the anus and cloaca), gently squeeze the skin near the urinary pore of the female fish's abdomen, collect urine using a centrifuge tube, and immediately store it in ice.

[0018] As a preferred embodiment, the crude extraction in step (2):

[0019] Mix the urine and ethanol evenly at a volume ratio of 1:1; perform an ice bath for 30 minutes to precipitate impurities and proteins; centrifuge at 4°C for 10 minutes (4000 rpm), and take the supernatant.

[0020] As a preferred embodiment, the filtration in step (2):

[0021] Filter the supernatant with absorbent cotton to obtain a clear crude extract of 17,20b-P pheromone, which can be sub-packaged and stored in a cryotube and stored at -20°C.

[0022] As a preferred embodiment, the fish-attracting liquid preparation in step (2):

[0023] The crude sex pheromone extract is diluted with reservoir water at a ratio of 1:5 (being too concentrated may lead to a reduction in the efficiency of attracting fish). Adding a small amount of gelatin can increase the viscosity, which helps with the slow release of the pheromone. The diluted fish-attracting liquid is filled into a plastic bottle to prepare a 17,20β-p sex pheromone solution.

[0024] As a preferred embodiment, in the step (4), the sex pheromone can be continuously released for 1 to 3 hours. The higher the water temperature, the shorter the release duration. The placement time of the fishing cage underwater can be shortened or extended according to the fish situation.

[0025] A trapping device for Oreochromis niloticus and its operation method based on 17,20β-p sex pheromone of the present invention uses a solution containing 17,20β-P extracted from the body fluid of Oreochromis niloticus for pheromone trapping, and has the following beneficial effects:

[0026] (a) Compared with traditional mechanical fishing means, using the endogenous sex pheromone in fish as a trapping agent not only helps to achieve directional fish attraction, but also can significantly reduce the environmental interference during the fishing process, reduce the damage of fishing tools to the local ecology, ensure the hormone activity through low-temperature and short-time operations, and the crude extraction process is simple and easy to implement, greatly improving the flexibility of on-site operations.

[0027] (b) Secondly, the preparation process of the crude extract retains a variety of bioactive components, and the multiple pheromone effects play a synergistic effect during the trapping process. Compared with traditional single baits, pheromone trapping can utilize the natural physiological effects of hormones to form a local high-concentration fish-attracting field in the trapping area, thereby attracting and aggregating individuals in the breeding period or before mating, and improving the fishing efficiency.

[0028] (c) The present invention can optimize the release curve of the trapping agent in the water body by appropriate dilution and adding gelatin, so that the pheromone can attract fish schools for a long time and can adapt to the actual situations of different water temperatures and flow rates in different waters.

[0029] (d) The technical solution of the present invention can reduce the interference to the ecosystem while meeting the fishing requirements, and has high environmental protection and sustainability value.

[0030] (e) The pheromone trapping method based on the solution containing 17,20β-P extracted from the urine of Oreochromis niloticus, with its advantages of simple operation, low cost, high-efficiency fish collection and environmental friendliness, provides a new technical approach worthy of promotion for controlling invasive fish. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the fishing cage in the present invention.

[0032] The symbols in the figure represent: 1. Bottle for placing fish-attracting liquid; 2. Fish inlet; 3. Flexible plastic sheet. Detailed implementation manners

[0033] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings: These embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0034] As Figure 1 shown, a tilapia zillii trapping device based on 17,20β-p pheromone includes a cage main body. The frame size of the cage main body is 50*50 cm, the length of the cage main body is 6 m, the frame of the cage main body is made of corrosion-resistant stainless steel wire, a mesh surface is covered around the frame, the mesh surface is made of nylon material, and the mesh size of the mesh surface is 5 mm.

[0035] The fish inlet 2 of the cage main body is in a funnel shape, and the fish inlet 2 is enlarged. A fish-attracting liquid placement bottle 1 is suspended in the cage main body. The fish-attracting liquid placement bottle 1 is a plastic bottle, and the plastic bottle is used to place fish-attracting liquid. A flexible plastic sheet 3 is added to the end of the fish inlet 2 to prevent the captured male and female fish with larger body sizes from escaping. Openings are provided on the bottle body of the plastic bottle in the cage main body to facilitate the diffusion of pheromone in water.

[0036] An operation method of a tilapia zillii trapping device based on 17,20β-p pheromone specifically includes the following operation steps:

[0037] (1) Select a suitable cage;

[0038] (2) Prepare a pheromone solution, including urine collection, crude extraction treatment, filtration, and fish-attracting liquid preparation. The specific operation steps are as follows:

[0039] Urine collection in (21):

[0040] Select sexually mature female tilapia zillii with a body length of 10 cm or more (there are 3 holes in front of the anal fin of the abdomen, including the anus, genital pore, and urinary pore; male tilapia zillii have 2 holes, including the anus and cloaca), gently squeeze the skin near the urinary pore on the abdomen of the female fish, collect urine using a centrifuge tube, and immediately store it in ice.

[0041] Crude extraction treatment in (22):

[0042] Mix the urine and ethanol evenly at a volume ratio of 1:1; perform ice bath for 30 minutes to precipitate impurities and proteins; centrifuge at 4°C for 10 minutes (4000 rpm), and take the supernatant.

[0043] Filtration in (23):

[0044] Filter the supernatant with absorbent cotton to obtain a clarified crude extract of 17,20b-pheromone, which can be dispensed and stored in a cryotube and stored at -20°C.

[0045] Preparation of the fish-attracting liquid in (24):

[0046] Dilute the crude extract of sex pheromone with reservoir water at a ratio of 1:5 (too concentrated may lead to a decrease in fish-attracting efficiency). Add a small amount of gelatin to increase viscosity, which helps the slow release of pheromone. Fill the diluted fish-attracting liquid into a plastic bottle to obtain a 17,20β-p sex pheromone solution.

[0047] (3) Select the trapping point: Select a gentle slope with a water depth of 1.5 - 3 meters, where the water body is relatively clear, the water flow is slow, the water temperature is 24 - 30°C, and a natural habitat with aquatic vegetation or stones is used as the trapping point;

[0048] (4) Place the trapping cage:

[0049] Place 1 cage at each trapping point. 3 - 5 trapping points can be set simultaneously to form a fish-attracting zone. The interval between each trapping point is 10 - 15 meters, which is convenient for judging the movement trend of the fish school. The sex pheromone can be continuously released for 1 - 3 hours, and the higher the water temperature, the shorter the release duration. The placement time of the cage underwater can be shortened or extended according to the fish situation.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A trapping device for Oreochromis niloticus based on 17,20β-p pheromone, characterized in that, It includes a cage main body. The frame size of the cage main body is 50*50 cm, and the length of the cage main body is 6 m. The frame of the cage main body is made of corrosion-resistant stainless steel wire, and a mesh surface is covered around the frame. The mesh surface is made of nylon material. The fish inlet of the cage main body is funnel-shaped, and the fish inlet is enlarged. A plastic bottle is suspended in the cage main body, and the plastic bottle is used to place fish attractant liquid.

2. A 17,20β-p sex pheromone-based tilapia trapping device according to claim 1, characterized in that: The mesh size of the mesh surface is 5 mm.

3. The trapping device for Oreochromis niloticus based on 17,20β-p pheromone according to claim 1, characterized in that, Flexible plastic sheets are added to the end of the fish inlet to prevent the escape of captured male and female fish with larger body sizes.

4. A trapping device for Oreochromis niloticus based on 17,20β-p pheromone according to claim 1, characterized in that, Openings are provided on the bottle body of the plastic bottle in the cage main body to facilitate the diffusion of pheromones in water.

5. An operation method of a tilapia zillii trapping device based on 17,20β-p sex pheromone as described in claim 1, specifically including the following operation steps: (1) Select a suitable cage. (2) Prepare the pheromone solution, including urine collection, crude extraction, filtration, and fish attractant liquid preparation. (3) Select a trapping point: Select a gentle slope with a water depth of 1.5 - 3 meters, relatively clear water, slow water flow, a water temperature of 24–30°C, and a natural habitat with aquatic vegetation or stones as the trapping point. (4) Place the trapping cage: Place 1 cage at each trapping point. 3 - 5 trapping points can be set simultaneously to form a fish attracting zone. The distance between each trapping point is 10 - 15 meters, which is convenient for judging the activity trend of the fish school.

6. The operating method of a trapping device for Oreochromis niloticus based on 17,20β-p pheromone according to claim 5, characterized in that, The urine collection in step (2): Select sexually mature female tilapia zillii with a body length of 10 cm or more, gently squeeze the skin near the urinary pore of the female fish's abdomen, collect urine using a centrifuge tube, and immediately store it in ice.

7. The operating method of a tilapia zillii trapping device based on 17,20β-p pheromone according to claim 5, characterized in that, The crude extraction in step (2): Mix the urine and ethanol evenly at a volume ratio of 1:1; perform an ice bath for 30 minutes to precipitate impurities and proteins; centrifuge at 4°C for 10 minutes, and take the supernatant.

8. The operating method of a trapping device for Oreochromis niloticus based on 17,20β-p pheromone according to claim 5, characterized in that, The filtration in step (2): Filter the supernatant with absorbent cotton to obtain a clarified crude extract of 17,20b-P pheromone, which can be aliquoted and stored in a cryogenic tube and stored at -20°C.

9. The operating method of a trapping device for Oreochromis niloticus based on 17,20β-p pheromone according to claim 5, characterized in that, The fish attractant liquid preparation in step (2): Dilute the crude pheromone extract with reservoir water at a ratio of 1:5, add a small amount of gelatin to increase viscosity, which helps the slow release of the pheromone. Fill the diluted fish attractant liquid into a plastic bottle to prepare a 17,20β-p sex pheromone solution.

10. The operating method of a trapping device for Oreochromis niloticus based on 17,20β-p pheromone according to claim 5, characterized in that, In step (4), the sex pheromone can be continuously released for 1 - 3 hours. The higher the water temperature, the shorter the release duration. The placement time of the cage underwater can be shortened or extended according to the fish situation.

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