Yangtze river cowfish water lifting netting gear suitable for circular breeding pond and using method thereof

Abstract

The invention belongs to the technical field of artificial breeding of cowfishes, and particularly relates to a water lifting netting gear for cowfishes in Yangtze River suitable for a circular breeding pond and a using method of the water lifting netting gear. The water lifting netting gear comprises a circular knotless net, a circular net periphery and a traction rope; the periphery of the circular net is arranged in the circumferential direction of the circular knotless net, and a plurality of traction ropes are arranged on the periphery of the circular net at equal intervals in the circumferential direction. Before water lifting, the netting gear enters the water through the side wall and is flatly laid at the bottom of the feeding pond, a diver transfers the traction rope to workers at the designated position, the workers pull the traction rope upwards at the same time at the constant speed to drive the netting gear to be horizontally lifted, and the diver lightly supports the belly of a cowfish to guide the cowfish to the edge of the pond to lift the water through a special stretcher. The knotless netting tool made of soft materials is adopted, stimulation to the Yangtze River cowfishes can be reduced, the accidental risks of water inhaling, net touching and the like possibly caused by operation stress are effectively reduced through rapid and accurate control over the height of the netting tool from the water surface, and a safe and efficient solution is provided for water extraction of the artificially fed Yangtze River cowfishes.

Description

Technical Field

[0001] This invention belongs to the field of artificial breeding technology for finless porpoises, and in particular, it relates to a water-lifting net suitable for circular breeding ponds for Yangtze finless porpoises and its usage method. Background Technology

[0002] Yangtze finless porpoise ( Neophocaena asiaeorientalis The Yangtze finless porpoise is a Class I protected animal in China and the only extant cetacean in the Yangtze River. It holds significant conservation and research value, primarily distributed in the middle and lower reaches of the Yangtze River and its connected lakes. It is a crucial indicator species for the health of the Yangtze ecosystem. Artificial breeding is a vital aspect of Yangtze finless porpoise conservation. Establishing artificial breeding populations and conducting artificial reproduction research are key to building a conservation barrier for the Yangtze finless porpoise and solidifying the goals of its rescue and protection.

[0003] Currently, my country has established two fully artificial breeding populations of Yangtze finless porpoises, with a total number exceeding 20. To ensure the health and safety of these porpoises, frequent out-of-water operations such as physical examinations, treatments, and transfers to different pools are necessary. Underwater operations are insufficient for these needs, necessitating out-of-water transfers. Using conventional nets for this purpose presents several challenges. First, the knotted structure and stiff material of the nets can easily cause abrasions to the porpoises' skin. Second, conventional operations require the nets to be vertically laid in the breeding pool and then horizontally pulled towards the pool wall. During this process, the porpoises' horizontal space is continuously compressed, forcing them to move and concentrate in the remaining space near the pool wall, ultimately allowing divers to capture them underwater and transfer them to stretchers. This method, with the net space compressing inwards, can easily trigger stress in the porpoises, leading to them touching the net or choking on water. Furthermore, to reduce these stress risks, the number of porpoises captured at one time is usually limited to two or less. Therefore, when the number of porpoises in the breeding pool is large, multiple capture operations are required. The aforementioned nets and operating methods not only accumulate stress risks but also significantly increase the difficulty of operation for divers, resulting in low work efficiency and high stress risks. Summary of the Invention

[0004] This invention aims to solve the problems of conventional nets causing abrasions, stress-induced contact with the net and choking during water retrieval operations, high operational difficulty, and low efficiency. It provides a safe and efficient water retrieval net and operation method to achieve the non-destructive and rapid retrieval of Yangtze finless porpoises.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A net for raising Yangtze finless porpoises in a circular rearing pond includes a circular knotless net, a circular net perimeter, and traction ropes; the circular net perimeter is arranged along the circumference of the circular knotless net, and multiple traction ropes are arranged at equal intervals along the circumference of the circular net perimeter.

[0006] As a further preferred option, the circular knotless net is a circular net formed by using a knotless plain weave process with nylon net rope.

[0007] As a further preferred option, nylon netting with a diameter of 5-7 mm can balance net strength and lightness; circular knotless netting with a diameter of 9-11 m can completely cover the breeding pond; and circular knotless netting with a mesh size of 4-6 cm can ensure good water passage and facilitate quick operation.

[0008] As a further preferred option, the outer perimeter of the circular net is woven from nylon ropes with a diameter of 11-13 mm along the edge of the circular knotless net, which serves to reinforce the circular knotless net.

[0009] As a further preferred option, the traction rope is made of 8 nylon net ropes with a diameter of 11-13 mm and a length of 4-6 m, with one traction rope set every 45° along the outer circumference of the circular net.

[0010] As a further preferred option, the traction rope is knotless connected to the outer perimeter of the circular net.

[0011] As a further preferred option, eight traction ropes are arranged circumferentially around the outer perimeter of the circular net.

[0012] A method for using a net suitable for catching Yangtze finless porpoises in a circular rearing pond includes the following steps: Step 1: Slowly lower the circular knotless net along the edge of the rearing pond to the bottom; Step 2: The diver slowly descends to the bottom of the pool and uses the traction ropes around the circular knotless net to drag the net horizontally, laying it flat against the bottom of the entire rearing pool. When operating, the diver should move slowly close to the bottom of the rearing pool to minimize disturbance to the Yangtze finless porpoise. At the same time, the diver should face upwards and closely monitor the activities of the Yangtze finless porpoise. Step 3: The diver swims slowly upwards close to the pool wall, passing the tow rope to the staff at the designated positions around the breeding pool in sequence. Then the diver slowly swims out of the breeding pool and waits at the pool side. At this time, the circular knotless net is still attached to the bottom of the breeding pool and the tow rope is attached to the pool wall. Step 4: Several staff members around the feeding pool simultaneously and at a uniform speed pull the traction rope to steadily and horizontally lift the circular knotless net from the bottom of the pool, causing the Yangtze finless porpoises to slowly swim towards the surface of the water until all the Yangtze finless porpoises in the feeding pool are lifted to about 50 cm above the water surface. Due to the limited vertical activity space, the Yangtze finless porpoises are in a near-floating state, reducing the risk of stress and contact with the net. Step 5: Two divers enter the rearing pool and slowly swim from the water above the circular knotless net to the vicinity of the target Yangtze finless porpoise. They work together to approach and restrain the porpoise from both sides at the same time, and gently support the porpoise's abdomen with their arms to keep the porpoise's blowhole above the water surface. After confirming that the porpoise is breathing normally and is not struggling, they slowly move towards the edge of the pool. Step Six: After the Yangtze finless porpoise is escorted to the pool, the staff will lay the stretcher flat in the water below the porpoise, making sure the stretcher is aligned with the direction of the porpoise. The stretcher will be brought closer to the porpoise, and the pectoral fins will be secured using the pre-drilled holes in the stretcher fabric. Then the stretcher will be closed and slowly lifted to complete the water retrieval operation.

[0013] As a further preferred option, in step four, the target height is 50 cm above the water surface.

[0014] As a further preferred option, in step six, two staff members each hold one side of the stretcher pole to unfold the stretcher and immerse it in the water for 20 cm. After the diver moves the Yangtze finless porpoise to the edge of the pool, the stretcher is moved under the Yangtze finless porpoise to complete the water retrieval operation.

[0015] Beneficial effects: The present invention has the following advantages: First, the water nets used in this project employ flexible nylon ropes and knotless plain weave technology. The softer knotless nets can significantly reduce the risk of skin abrasions and stress responses in Yangtze finless porpoises.

[0016] Secondly, this method of raising the fish can complete the raising of all Yangtze finless porpoises in the pool in a single net release, avoiding repeated net release and retrieval, greatly improving operational efficiency, and effectively reducing the cumulative stress risk caused by multiple disturbances.

[0017] Third, by using a horizontal overall lifting and effective control of vertical space, the spatial pressure caused by traditional horizontal compression is eliminated, effectively preventing stress in the Yangtze finless porpoise.

[0018] Fourth, the Yangtze finless porpoises awaiting retrieval are in a near-floating state, which facilitates their transfer by staff and reduces operational difficulty.

[0019] Fifth, in case of Yangtze finless porpoises experiencing stress, the net can be quickly lowered using a traction rope to alleviate the stress, or the net can be rapidly lifted to achieve quick retrieval and disposal. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the circular rearing pond net for Yangtze finless porpoises of the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] like Figure 1 As shown, a net for raising Yangtze finless porpoises in a circular rearing pond includes a circular knotless net 1, a circular outer perimeter 2, and traction ropes 3; the circular outer perimeter 2 is arranged around the circular knotless net 1, and multiple traction ropes 3 are arranged at equal intervals along the circumference of the circular outer perimeter 2.

[0023] The circular knotless net 1 is a circular net formed by using a knotless plain weave process with nylon net rope. The diameter of the nylon net rope is 6 mm, and the diameter of the circular knotless net 1 is 10 m. The use of flexible nylon net rope knotless weaving can reduce the risk of abrasions to Yangtze finless porpoises. Nylon material is more wear-resistant and tensile-resistant than polyester fiber, and has a longer service life.

[0024] The circular knotless net with a mesh size of 5 cm ensures good water passage and is less likely to entangle the fins and tail fins of the Yangtze finless porpoise, thus improving the efficiency of the retrieval operation while ensuring safety.

[0025] The size of the circular knotless net is close to the diameter of the rearing pond. This size is determined according to the size of the rearing pond. It can completely cover the rearing pond and avoid the accumulation of excess nets in the pond, reducing the risk of Yangtze finless porpoises getting tangled in the nets.

[0026] The outer perimeter 2 of the circular net is made of a thickened nylon rope (12 mm in diameter) to maintain the shape of the circular knotless net 1 and to provide reinforcement for traction operations.

[0027] It is woven from 8 nylon net ropes with a diameter of 12 mm and a length of about 5 m. One rope is set every 45° along the outer perimeter of the circular net and is connected to the knotless rope along the outer perimeter of the circular net for use as a traction net.

[0028] A method for raising Yangtze finless porpoises based on the water-lifting net of the present invention comprises the following steps: Step 1: Slowly lower the net into the bottom of the pond from one side.

[0029] Step 2: The diver slowly descends to the bottom of the pool and then drags the traction rope across the entire rearing pool, causing the circular knotless net 1 to be laid flat and adhered to the entire rearing pool.

[0030] Step 3: The diver swims upwards along the pool wall with the tow rope, passing the tow rope 3 to the staff at designated positions around the breeding pool. Then the diver slowly swims out of the breeding pool.

[0031] Step Four: Eight staff members stand at equal intervals around the rearing pool and simultaneously pull the traction rope 3 to lift the net horizontally from the bottom of the pool at a uniform speed until all Yangtze finless porpoises in the pool are raised to about 50 cm above the water surface. This functions similarly to an aquatic animal medical lift platform, reducing the difficulty of operation for personnel and the stimulation to the Yangtze finless porpoises during the lifting operation. Closely monitor the activity of the Yangtze finless porpoises. In case of emergencies such as net collision, stop pulling and take two measures depending on the number of Yangtze finless porpoises: If there are more than two animals, quickly loosen the traction rope 3 and quickly put the circular knotless net 1 back to the bottom of the pool. Continue the operation after the Yangtze finless porpoises have calmed down; if there are no more than two animals, quickly and steadily lift the traction rope to completely lift the net out of the water and bring it to shore. Staff should immediately transfer the Yangtze finless porpoises to a stretcher and perform procedures such as soothing and examination.

[0032] Step 5: Two divers enter the rearing pool and slowly swim over the nets to the vicinity of the target Yangtze finless porpoise. Each diver gently supports the porpoise's abdomen with their arms, keeping its blowhole above the water to prevent choking. The two divers work together to slowly move towards the pool edge. Once the divers have escorted the porpoise to the edge, two staff members lay a stretcher flat beneath it. The divers then carefully place the porpoise's pectoral fins into the pre-drilled holes in the stretcher fabric to prevent twisting and fin fractures. The stretcher is then closed and lifted out of the water, completing the retrieval operation. After all targets have been retrieved, the nets are immediately collected, washed, dried, and stored.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A net for catching Yangtze finless porpoises in a circular rearing pond, characterized in that: It includes a circular knotless net (1), a circular net outer perimeter (2) and traction ropes (3); the circular net outer perimeter (2) is arranged around the circular knotless net (1), and multiple traction ropes (3) are arranged at equal intervals around the circular net outer perimeter (2).

2. The Yangtze finless porpoise catching net suitable for circular rearing ponds according to claim 1, characterized in that: The circular knotless net (1) is a circular net formed by using a knotless plain weave process with nylon net rope.

3. The Yangtze finless porpoise catching net suitable for circular rearing ponds according to claim 2, characterized in that: The diameter of the nylon net rope is 5-7 mm; the diameter of the circular knotless net (1) is 9-11 m; the mesh size of the circular knotless net (1) is 4-6 cm.

4. The Yangtze finless porpoise catching net suitable for circular rearing ponds according to claim 1, characterized in that: The outer periphery (2) of the circular net is woven from nylon rope with a diameter of 11-13 mm along the edge of the circular knotless net (1).

5. A net for catching Yangtze finless porpoises in a circular rearing pond according to claim 1, characterized in that: One of the aforementioned traction ropes (3) is woven from 8 nylon net ropes with a diameter of 11-13 mm and a length of 4-6 m. A traction rope (3) is set every 45° along the outer perimeter (2) of the circular net.

6. A net for catching Yangtze finless porpoises in a circular rearing pond according to claim 1 or 5, characterized in that: The traction rope (3) is knot-free connected to the outer perimeter (2) of the circular net.

7. A net for catching Yangtze finless porpoises in a circular rearing pond according to claim 1, characterized in that: The outer perimeter (2) of the circular net is circumferentially arranged with eight traction ropes (3).

8. The method of using the Yangtze finless porpoise catching net suitable for circular rearing ponds according to claim 1, characterized in that, Includes the following steps: Step 1: Slowly lower the circular knotless net (1) along the edge of the rearing pond to the bottom of the pond; Step 2: The diver slowly descends to the bottom of the pool and uses the traction ropes (3) around the circular knotless net (1) to drag the circular knotless net (1) horizontally, so that the circular knotless net (1) is laid flat and attached to the bottom of the entire breeding pool. Step 3: The diver swims upward close to the pool wall and passes the tow rope (3) to the staff at the designated positions around the breeding pool. Then the diver slowly swims out of the breeding pool and waits at the pool side. Step 4: Multiple staff members around the breeding pool simultaneously and at a uniform speed drag the traction rope (3) to lift the circular knotless net (1) steadily and horizontally from the bottom of the pool until all the Yangtze finless porpoises in the breeding pool are lifted to the target height. Step 5: Two divers enter the breeding pool, slowly swim to the vicinity of the target Yangtze finless porpoise, approach from both sides and restrain it, gently support the Yangtze finless porpoise's abdomen with their arms to keep the porpoise's blowhole above the water surface and slowly move it towards the edge of the pool. Step Six: After the Yangtze finless porpoise is escorted to the pool, the staff will lay the stretcher flat under the porpoise, use the pre-drilled holes in the stretcher fabric to secure the pectoral fins, then close the stretcher and slowly lift it to complete the water retrieval operation.

9. The method of using the Yangtze finless porpoise catching net suitable for circular rearing ponds according to claim 1, characterized in that: In step four, the target height is 50 cm above the water surface.

10. The method of using the Yangtze finless porpoise catching net suitable for circular rearing ponds according to claim 1, characterized in that: In step six, two staff members each hold one side of the stretcher pole and unfold the stretcher, immersing it 20 cm in the water. After the diver moves the Yangtze finless porpoise to the edge of the pool, the stretcher is moved under the Yangtze finless porpoise to complete the water retrieval operation.

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