Schizothorax fish staging and layering bait rearing field and construction method thereof

Abstract

The invention discloses a staging and layering bait rearing field for schizothorax fishes and a construction method thereof, three kinds of net cage units (fine, medium and large pores) matched with the sizes of the schizothorax fishes in different growth stages are designed, and are filled with specific bait biological cultivation matrixes to form different functional units, so that staging bait habitat construction is realized. Then, the functional units are arranged in a vertical space according to the activity water layer preferred by the fishes at each stage, so that layered ecological niche space construction is formed; finally, all the units are integrated into an organic whole through flexible linkage, and effective circulation of water, bait and fishes in the system is ensured. According to the invention, a composite structure which is layered in a vertical space and staging in an internal habitat is constructed, a physical inhabitation space and biological bait production are integrated into a whole, and a diversified bait cable environment in a natural river is dynamically simulated.

Description

Technical Field

[0001] This invention belongs to the field of aquatic ecological restoration technology, specifically relating to a staged and stratified feeding ground for schizothorax fish and its creation method. Background Technology

[0002] Schizothorax are typical representatives of cold-water fish in high-altitude areas. Due to their inhabitation of fast-flowing, low-temperature, high-dissolve-oxygen canyon rivers and lakes, they exhibit high ecological sensitivity, and their population stability is crucial for maintaining aquatic biodiversity. Their habitat selection shows distinct developmental stages, typically favoring rocky bottom environments. Adults prefer shallow, fast-flowing areas, while juveniles rely on slow-flowing or still shallow waters. Their dietary requirements change significantly with growth stages. Juveniles primarily feed on zooplankton and attached algae, gradually shifting to a diet mainly consisting of attached algae, aquatic plant debris, and benthic invertebrates as they grow.

[0003] However, due to human activities such as water conservancy projects and river regulation, the homogenization and fragmentation of natural river habitats have become prominent problems, leading to the severe degradation or loss of natural feeding grounds. This has made it impossible to provide a suitable feeding environment for schizothorax fish, which has become a key bottleneck restricting their resource recovery.

[0004] With increasing demands for ecological protection and fisheries resource management, the creation of riverine fish feeding grounds has gained growing attention. Feeding grounds are crucial for fish to forage and inhabit, and their creation aims to improve fish habitats and enhance fish populations and diversity through artificial intervention. Early stages primarily involved simple physical modifications, such as placing rocks and timber, to provide habitats and foraging grounds. The intermediate stage incorporated ecological engineering concepts, combining hydrological, geomorphological, and ecological knowledge to design more complex feeding ground structures. The modern stage utilizes advanced technologies such as GIS, remote sensing, and ecological models for precise design and monitoring to ensure the ecological benefits of feeding grounds. Key technologies include constructing artificial reefs, driftwood, and rocks to simulate natural habitats; planting aquatic plants to provide food sources and shelter; optimizing fish habitat conditions by adjusting hydrological parameters such as water flow velocity and depth; and using sensors and remote sensing technology to monitor the ecological status of feeding grounds in real time.

[0005] For schizothorax fish, current habitat creation techniques have the following limitations: First, existing feeding ground creation methods are too general and lack detailed consideration of the stage-specific characteristics of fish life history. Existing feeding ground creation techniques, such as the patent "A Method for Creating Spawning Grounds, Feeding Grounds, and Hideouts for Fish" (Patent Publication No.: CN118077617A), still focus on providing overall environmental conditions for habitats with different ecological functions such as spawning, feeding, and hiding, without further addressing the core issue of how to systematically meet the differentiated feeding needs of the same fish species at different developmental stages within the same feeding ground. Second, existing technologies do not adequately consider the spatial stratification of fish niches, resulting in a simplistic habitat structure. For example, the Chinese patent "Structure and Method for Creating Fish Habitat in Integrated Water, Wind and Solar Basin" (Patent Publication No.: CN118648566A) mentions the stratified habitat characteristics of fish, but its structural design is to cope with changes in hydrological conditions and to simply physically separate different water layers. It fails to systematically couple the vertical spatial structure with the food supply, hydrological conditions and shelter needs of specific developmental stages. Another example is "A Fish Three-Field Two-Channel Interconnection and Reservoir Ecological Trap Avoidance System" (Patent Publication No.: CN116289787A), which connects the feeding ground, spawning ground and overwintering ground by constructing connecting channels to help fish avoid ecological traps in the reservoir, but it is not specifically designed for schizothorax.

[0006] In addition, although there are specific restoration technologies for schizothorax spawning grounds, such as “A method for constructing a schizothorax spawning ground in a canyon with reduced water flow” (patent publication number: CN115467281A), these methods mainly serve the breeding stage and are not well integrated with the feeding grounds in terms of function and space.

[0007] In conclusion, there is an urgent need for a feeding ground creation method that can accurately respond to the unique life history strategies of schizothorax fish, thereby effectively supporting the continuous reproduction and recovery of schizothorax fish populations. Summary of the Invention

[0008] Based on the above-mentioned prior art, the present invention provides a staged and layered feeding ground for schizothorax fish and its construction method. The present invention constructs a composite structure that is layered in vertical space and staged in internal habitat, integrating physical habitat space with biological food production, and dynamically simulating the diverse feeding environment in natural rivers.

[0009] The technical solution adopted to achieve the above-mentioned objectives of this invention is as follows: A staged, stratified feeding ground for schizothorax fish is proposed, comprising one or more tree-like three-dimensional habitat structures deployed in a relatively slow-moving area of ​​the target water body. Each three-dimensional habitat structure is submerged in water. The three-dimensional habitat structure includes a central main support component, bottom ecological components, intermediate ecological components, and an upper ecological component. The central main support component is fixed to the bottom of the target water body by gravity. The bottom, intermediate, and upper ecological components are flexibly connected to the central main support component. The bottom, intermediate, and upper ecological components are located at different points along the water flow in the target water body. The area is divided into a surface flow zone, a main flow zone, and a bottom flow zone. The bottom ecological components contain bottom food cultivation units that provide food for adult fish. The intermediate ecological components contain intermediate layer food cultivation units that provide food for sub-adult fish. The upper ecological components contain upper layer food cultivation units that provide food for juvenile fish. The central main support component, bottom ecological components, intermediate ecological components, and upper ecological components are all porous channel structures with different directions and interconnected with each other. The channels in the bottom ecological components, intermediate ecological components, and upper ecological components are connected to the channels in the central main support component.

[0010] The central main support component includes a columnar gabion body, which is filled with irregular stones. The filling volume is 65%-85% of the volume of the gabion body. A large number of porous pores of different directions, sizes and interconnections are formed between the stones. The large number of interconnected porous pores constitute channels that run through all directions.

[0011] The bottom layer ecological components, the middle layer ecological components, and the top layer ecological components do not come into contact with each other.

[0012] The underlying ecological components include multiple first net cage units, each comprising a first net cage body filled with a bottom food cultivation unit. These first net cage units are evenly distributed circumferentially around a central main support component, and each first net cage unit is flexibly connected to the bottom of the central main support component. Each first net cage unit is placed on the bottom of the target water area. The intermediate ecological components include multiple second net cage units, each comprising a second net cage body filled with an intermediate food cultivation unit. These second net cage units are evenly distributed circumferentially around the central main support component, and each second net cage unit is flexibly connected to the central main support component. The upper ecological components include multiple third net cage units, each comprising a third net cage body filled with an upper food cultivation unit. These third net cage units are evenly distributed circumferentially around the central main support component, and each third net cage unit is flexibly connected to the central main support component. The mesh size of the first, second, and third net cage bodies decreases sequentially.

[0013] The meshes at the top of each of the first, second, and third mesh cage units are respectively positioned and connected to the corresponding meshes on the central main support component by locking, and the first, second, and third mesh cage units are respectively fixedly connected to the corresponding meshes on the central main support component by binding.

[0014] The volumes of the first, second, and third cage bodies decrease sequentially.

[0015] There are four first mesh cage units, which are arranged in a cross shape. There are two second mesh cage units, which are arranged symmetrically about the central main support member. There are two third mesh cage units, which are arranged symmetrically about the central main support member. The second and third mesh cage units are staggered in the vertical direction.

[0016] The first gabion body is rectangular, the first gabion unit is cubic, and the second and third gabion units are both regular prisms.

[0017] The bottom layer of the food cultivation unit is a mixture of coarse gravel and slow-release organic matter blocks. The middle layer of the food cultivation unit includes multiple loosely bundled bodies formed by binding plant stems. The interior and surface of each loosely bundled body are filled with a granular mixture of cladoceran dormant eggs and natural plant fibers. The middle layer of the food cultivation unit includes multiple palm bark bundles made of palm bark. The palm bark bundles have a broom-like structure or a curtain-like structure. The surface of the palm bark bundles is covered with a high density of microalgae communities.

[0018] A method for creating a staged and stratified feeding ground for schizothorax fish includes the following steps: S1, prefabricated central main support components, first wire mesh cage unit, second wire mesh cage unit and third wire mesh cage unit; S2. Determine the target water area, level the bottom of the area with slower water flow, and then place the central main support component on the bottom of the selected location in the area with slower water flow. S3. Distribute multiple first net cage units evenly around the central main support component, and "sit" each first net cage unit at the corresponding position at the bottom of the central main support component, so that the bottom of each first net cage unit is close to the bottom of the selected position in the area where the water flow in the target water is relatively slow. The construction of the bottom ecological component is completed. S4. Distribute multiple second cage units evenly around the central main support component, and suspend each second cage unit at the corresponding position in the middle of the central main support component. The construction of the intermediate layer ecological component is completed. S5. Distribute multiple third mesh cage units evenly around the central main support component, and suspend each third mesh cage unit at the corresponding position on the central main support component. The upper ecological component is now complete. S6. At this point, a three-dimensional habitat structure component is completed. The three-dimensional habitat structure is submerged in the area of ​​the target water body where the water flow is relatively slow. The bottom ecological component, the middle ecological component, and the upper ecological component are located in the surface flow area, the main flow area, and the bottom area of ​​the area where the water flow is relatively slow, respectively. If multiple three-dimensional habitat structures need to be constructed, repeat steps S2-S5 until all three-dimensional habitat structures are constructed and the staged and layered feeding grounds for schizothorax fish are created.

[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. This invention designs three types of net cage units (fine, medium, and large pore sizes) that match the different growth stages of schizothorax fish, and fills them with a specific food biological cultivation substrate to form different functional units, thereby creating staged food habitats. Furthermore, based on the preferred water layers of fish at each stage, these functional units are arranged vertically to create stratified ecological niche spaces. Finally, all units are integrated into an organic whole through flexible connections, ensuring the effective flow of water, food, and fish within the system.

[0020] 2. This invention integrates a flexible, interconnected, porous net cage system that combines bait production, spatial structure creation, and hydrological environment control. It precisely meets the differentiated feeding and shelter needs of schizothorax fish at different developmental stages (stages) from juvenile to adult and at different water layers (layers), thereby effectively improving the foraging efficiency and survival rate of schizothorax fish.

[0021] 3. This invention, through phased design and hierarchical layout, achieves a high degree of matching between food production, spatial structure, and hydrological conditions and the feeding habits and niche requirements of schizothorax fish at different growth stages. This method overcomes the limitations of traditional single-structure approaches for multiple fish species, significantly improving the utilization efficiency of a unit habitat and the growth performance of fish, thereby enhancing the precision and efficiency of habitat creation.

[0022] 4. This invention provides an initial seed source and suitable substrate for the rapid establishment and long-term reproduction of prey organisms by pre-implanting microalgae substrate, dormant egg binding units, and slow-release organic matter blocks. This method transforms the traditional passive reliance on natural recovery into active, directional cultivation, which can rapidly build and stably maintain a high level of prey organism productivity, achieving proactive and sustainable prey supply.

[0023] 5. This invention employs a flexible link design, integrating different functional net cage units into a physically connected and functionally complementary organic whole. This structure promotes the circulation and diffusion of water, nutrients, and food organisms within the system, facilitating the free movement of fish between different ecological niches and strengthening the ecological connections between different food modules. This enhances the overall stability of the feeding ground system and its resistance to external disturbances, demonstrating the synergy and stability of the structure.

[0024] 6. This invention primarily uses environmentally friendly materials such as natural stone and plant fibers, avoiding secondary pollution. The net cage structure possesses excellent durability and erosion resistance, adapting to river hydrological dynamics. Furthermore, it only requires targeted replenishment of bait units in the later stages, resulting in low maintenance costs. It has good engineering applicability and promotional value, demonstrating the ecological and economic benefits of implementing this foraging ground project. Attached Figure Description

[0025] Figure 1 This is a three-dimensional diagram of the habitat structure.

[0026] Figure 2 This is the front view of the three-dimensional habitat structure.

[0027] Figure 3 This is a schematic diagram of the internal structure of the central main support component.

[0028] Figure 4 This is a schematic diagram of the internal structure of the first wire mesh cage unit.

[0029] Figure 5 This is a schematic diagram of the internal structure of the second wire mesh cage unit.

[0030] Figure 6 This is a schematic diagram of the internal structure of the third wire mesh cage unit.

[0031] Figure 7 This is a schematic diagram showing the connection method between the second wire mesh unit and the central main support component.

[0032] Among them, 1-Central main support component: 101-Gabion body, 102-Block stone; 2-Underlying ecological components: 201-First wire mesh cage unit: 2011 - First cage body, 2012 - Coarse gravel, 2013 - Slow-release organic matter block; 3-Intermediate layer ecological components: 301-Second wire mesh cage unit: 3011 - Second cage body, 3012 - Loose binding body, 3013 - Clump-like mixture; 4-Upper-layer ecological components: 401-Third wire mesh cage unit: 4011 - Third cage body, 4012 - Palm bark bundle; 5-U-shaped shackle; 6- Stainless steel cable ties. Detailed Implementation

[0033] The staged and stratified feeding ground for schizothorax fish of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] Example 1 The staged and stratified feeding grounds for schizothorax fish provided in this embodiment include setting up one or more three-dimensional habitat structures in a tree-like pattern in areas of the target waters where the water flow is relatively slow. Figure 1-2 As shown, the three-dimensional habitat structure includes a central main support component 1, a bottom ecological component 2, a middle ecological component 3, and an upper ecological component 4. The three-dimensional habitat structure is submerged in water.

[0035] like Figure 3 As shown, the central main support component 1 includes a square columnar gabion body 101, which is 1m long and 1m wide, and 2.4m high. The gabion body 101 is filled with irregularly shaped stones 102 with a particle size of 200-500mm, with a filling density of approximately 85% of the gabion body's volume. Numerous interconnected pores of varying directions and sizes are formed between the stones 102, creating channels that traverse all directions. The central main support component 1 has a very large self-weight and is fixed to the bottom of a relatively slow-flowing area of ​​the target water body by gravity, providing a stable base for the entire system.

[0036] The underlying ecological component 2 includes four first net cage units 201, such as... Figure 4 As shown, the first net cage unit 201 includes a cubic first net cage body 2011 with a side length of 1.0m and a mesh size of 30-50mm. The first net cage unit 201 is filled with a bottom feed cultivation unit, which is a mixture of coarse gravel 2012 (particle size 30-80mm) and slow-release organic matter blocks 2013 (approximately 1-2kg per block). The coarse gravel 2012 accounts for 70% of the total volume, and the slow-release organic matter blocks 2013 account for 30%. The bottom ecological components 2 are interconnected through the pores between the coarse gravel 2012 and the slow-release organic matter blocks 2013, forming channels that communicate with the channels of the central main support component 1.

[0037] Four first cage units 201 are distributed around the central main support member 1, forming a cross shape. Each first cage unit 201 is fixed to the bottom of the central main support member 1 and is placed on the bottom of the area where the water flow in the target water is relatively slow.

[0038] The mesh at the top of each first cage unit 201 is connected to the corresponding mesh on the central main support member 1 via U-shaped shackles. The U-shaped shackles act like locks, locking each first cage unit 201 onto the central main support member 1. At the same time, each first cage unit 201 is fixed to the corresponding position on the central main support member 1 by binding.

[0039] In the bottom ecological niche (adult fish area), four first net cage units 201 are arranged symmetrically in a cross shape around the bottom periphery of the central main support component 1, forming a stable base. The first net cage unit 201 forms a complex cave system through large-scale internal gaps, providing ideal hiding places for the schizothorax adult fish. The first net cage unit 201 is located in the relatively calm deep bottom area, suitable for the adult fish to carry out benthic feeding activities.

[0040] The intermediate layer ecological component 3 includes two second net cage units 301, such as Figure 5 As shown, the second net cage unit 301 includes a second net cage body 3011 in the shape of a regular square prism. The second net cage body 3011 has a length of 0.8 meters, a width of 0.8 meters, and a height of 0.6 meters. The mesh size of the second net cage body 3011 is 15-20 mm. The second net cage body 3011 is filled with an intermediate layer of food cultivation unit. The intermediate layer of food cultivation unit includes multiple loosely bound bodies 3012 formed by binding reed stalks. The interior and surface of each loosely bound body 3012 are filled with a clump-shaped mixture 3013 of cladoceran dormant eggs and coconut husk fibers. The intermediate layer ecological components 3 are interconnected through the gaps between the loosely bound bodies 3012 to form channels. The channels of the intermediate layer ecological components 3 are interconnected with the channels of the central main support component 1.

[0041] Two second cage units 301 are located around the central main support member 1. The two second cage units 301 are centrally symmetrical about the central main support member 1. The two second cage units 301 are connected to one of the two side walls of the central main support member 1. The edge of each second cage unit 301 in the height direction is on the same plane as the corresponding edge of the central main support member 1 in the height direction. The two second cage units 301 are distributed at the same horizontal height, and the vertical distance between the bottom of the two second cage units 301 and the bottom of the central main support member 1 is 1.2 meters.

[0042] like Figure 7 As shown, the mesh at the top of each second cage unit 301 is connected to the corresponding mesh on the central main support member 1 by a U-shaped shackle 5. The U-shaped shackle acts like a lock, locking each second cage unit 301 onto the central main support member 1. At the same time, each second cage unit 301 is fixed to the corresponding position on the central main support member 1 by binding (stainless steel cable ties 6).

[0043] In the mid-level ecological niche (subadult zone), two second net cage units 301 are centrally and symmetrically connected to the outer periphery of the central main support component 1. The second net cage unit 301 is located in the mainstream area with the highest water flow velocity. Through a specific arrangement, it disturbs the water flow and forms a vortex zone of suitable size around the unit, providing a gathering place for zooplankton and perfectly adapting to the schooling and feeding habits of subadult schizothorax.

[0044] The upper ecological component 4 includes two third net cage units 401, such as Figure 6 As shown, the third net cage unit 401 includes a third net cage body 4011 in the shape of a regular square prism. The third net cage body 4011 is 0.6 meters long, 0.6 meters wide, and 0.4 meters high, and the mesh size of the third net cage body 4011 is 5-10 mm. The third net cage body 4011 is filled with an upper food cultivation unit, which includes multiple palm bark bundles 4012 (approximately 30 cm in length) made of palm bark. The palm bark bundles 4012 have a broom-like or curtain-like structure. When the palm bark bundles 4012 have a broom-like structure, the small end of the palm bark bundles 4012 faces downward, and the surface of the palm bark bundles 4012 is covered with a high-density microalgae community. The upper ecological components 4 are interconnected through the gaps between adjacent palm bark bundles 4012 to form channels, and the channels of the upper ecological components 4 are interconnected with the channels of the central main support component 1.

[0045] Two third cage units 4011 are located around the central main support member 1, and are centrally symmetrical about the central main support member 1. The two third cage units 4011 are connected to the other two side walls of the central main support member 1. The edges of each third cage unit 401 in the height direction are on the same plane as the corresponding edges of the central main support member 1 in the height direction, and the second cage unit 301 and the third cage unit 401 are staggered in the vertical direction. The two third cage units 401 are distributed at the same horizontal height, and the vertical distance between the bottom of the two third cage units 401 and the bottom of the central main support member 1 is 2 meters.

[0046] The mesh at the top of each third cage unit 401 is connected to the corresponding mesh on the central main support member 1 via U-shaped shackles. The U-shaped shackles act like locks, locking each third cage unit 401 onto the central main support member 1. At the same time, each third cage unit 301 is fixed to the corresponding position on the central main support member 1 by binding.

[0047] In the surface ecological niche (juvenile fish area), two third net cage units 3012 are centrally and symmetrically arranged on the top periphery of the central main support component 1. The third net cage unit 3012 is located in the surface shallow water area with sufficient light. Its fine structure provides the maximum attachment area for microalgae growth, while creating a safe foraging environment for juvenile fish with weak swimming ability.

[0048] The central main support component 1 is flexibly linked to each ecological component through U-shaped shackles and binding (allowing for micro-displacement and buffering). This allows the three-dimensional habitat structure to undergo limited and minute relative displacement or rotation when subjected to water flow impact, external force traction, or slight changes in the foundation. This disperses concentrated stress and prevents rigid damage to the three-dimensional habitat structure, thereby ensuring the long-term stability of the system in complex underwater environments.

[0049] The following describes in detail the method for creating a staged and stratified feeding ground for schizothorax fish according to the present invention, in conjunction with the above-described apparatus.

[0050] Example 2 This embodiment was implemented in a wide, slow-flowing valley of a river. This river section has a suitable water depth gradient (1.0-3.5 meters) and flow velocity (0.1-0.5 meters / second), and its native habitat is relatively simple. Now, a feeding ground for schizothorax is being created in this river section. The specific creation method is described in detail below.

[0051] Prefabrication of components and units 1.1 Prefabrication of Central Main Support Component 1 A square columnar gabion body 101 with a square cross-section (side length 1.0 meter) and a height of 2.4 meters is constructed using high-strength galvanized steel wire mesh. The gabion body 101 is filled with irregularly shaped stones 102 with a particle size of 200-500 mm, at a filling density of approximately 85% of the gabion body 101's volume. During filling, attention is paid to the stacking method of the stones 102 to ensure a large number of interconnected pores of varying orientations and sizes, forming channels that flow through the gabion body in all directions.

[0052] 1.2 Prefabrication of the first wire mesh cage unit 201 Four cubic first mesh cage bodies 2011, each with a side length of 1.0 meter, are constructed using Galfan steel wire mesh with a aperture of 30-50 mm. Each first mesh cage body 2011 is filled with a mixture of coarse gravel and slow-release organic matter blocks. The coarse gravel 2012 (particle size 30-80 mm) accounts for 70% of the total volume, forming the main frame; the slow-release organic matter blocks 2013 account for 30% of the total volume and are evenly incorporated into the gaps between the coarse gravel.

[0053] The first net cage unit 201, with its large mesh size (30-50mm), provides ample internal space, allowing adult Schizothorax fish to easily enter and feed. The slow-release organic block 2013, made from decomposed plant stalks and leaves, slowly releases nutrients in the water, promoting biofilm growth and attracting and nourishing benthic organisms such as chironomid larvae and oligochaetes, thus providing adult fish with benthic food and a suitable feeding environment.

[0054] 1.3 Prefabrication of the second wire mesh cage unit 301 Two second net cage bodies 3011, each 0.8 meters long, 0.8 meters wide, and 0.6 meters high, are constructed using Galfan wire mesh with a 15-20 mm aperture. First, cladoceran dormant eggs are mixed evenly with moist coconut fiber at a volume ratio of 1:50 to form a clump-like mixture 3013. Then, a loosely bound body 3012, approximately 30 cm long and 15 cm in diameter, is constructed using reeds. The clump-like mixture 3013 containing the dormant eggs and coconut fiber is then evenly filled and fixed into the interior and surface of the loosely bound body 3012, forming an intermediate feeding unit. Finally, this intermediate feeding unit is filled into each second net cage body 3011.

[0055] The second net cage unit 301, with a mesh size of 15-20mm, allows sub-adult schizothorax fish to move freely while providing hiding and breeding space for zooplankton. When the second net cage unit 301 is placed in water, the moist and permeable environment activates the hatching of dormant eggs. The hatched zooplankton larvae feed on organic debris and microorganisms attached to coconut husk fibers and reproduce rapidly under the protection of the loose binding. The second net cage unit 301 provides a stable and high-quality source of zooplankton food for sub-adult schizothorax fish.

[0056] 1.4 Prefabrication of the third wire mesh cage unit 401 Two 0.6-meter-long, 0.6-meter-wide, and 0.4-meter-high regular square prism-shaped third net cage bodies 4011 are constructed using Galfan wire mesh with a 5-10mm aperture. First, palm bark is torn into fine bundles, approximately 20 bundles are taken, and the base ends of each bundle are tied together with corrosion-resistant rope to form a palm bark bundle 4012 with a length of approximately 30cm and a large specific surface area, resembling a broom. The palm bark bundles are then pre-soaked in a fertile pond rich in diatoms and green algae for 3-5 days, allowing a high-density microalgae community to fully adhere to the fiber surface, forming an upper food cultivation unit. Finally, each third net cage body 4011 is filled with this upper food cultivation unit.

[0057] The third net cage unit 401, with its small mesh size (5-10 mm), provides effective shelter for juvenile fish, preventing them from being swept away by the water flow or preyed upon by predators. When the third net cage unit 4011 is placed in the water, the juvenile fish can feed directly in the fiber clusters, solving the problem of finding suitable, high-density microalgae food during their initial feeding stage.

[0058] Construction of three-dimensional habitat structure 2.1 Construction of Central Main Support Component 1 The bottom of the selected area in the wide valley and slow-flowing zone of the river was simply leveled, and the central main support component 1 was vertically hoisted and placed in the selected position using lifting equipment to ensure that it was stably placed on the bottom.

[0059] 2.2 Construction of Underlying Ecological Component 2 Four first cage units 201 are symmetrically placed around the bottom of the central main support member 1, so that the four first cage units 201 are distributed in a cross shape. Using U-shaped shackles 5, the top of each first cage unit 201 is "hung" at the corresponding position at the bottom of the central main support member, so that the bottom of each first cage unit 201 is close to the bottom of the selected area of ​​the wide valley slow flow zone of the river. Then, stainless steel cable ties 6 are used to axially bind the four first cage bodies 2011 to the gabion body 101, and the construction of the bottom ecological component is completed.

[0060] 2.3 Construction of intermediate layer ecological component 3 Two second cage units 301 are placed on the outer periphery of the central main support member 1, so that the two second cage units 301 are centrally symmetrical about the central main support member 1. Using U-shaped shackles 5, the top of each second cage unit 301 is suspended from the corresponding position in the middle of the central main support member 1, with a vertical distance of 1.2 meters between the bottom of each second cage unit 301 and the bottom of the central main support member 1. Then, stainless steel cable ties are used to bind the two second cage bodies 3011 to the gabion body 101, completing the construction of the intermediate ecological component 3.

[0061] 2.4 Construction of Upper Interlayer Ecological Component 4 Two third cage units 401 are placed around the central main support member 1, making the two second cage units 401 centrally symmetrical about the central main support member 1. Each third cage unit 401 is suspended from its top position on the corresponding part of the central main support member 1 using U-shaped shackles 5, with a vertical distance of 2 meters between the bottom of each third cage unit 401 and the bottom of the central main support member 1. Then, stainless steel cable ties 6 are used to bind the two third cage bodies 401 to the gabion body 101, completing the upper ecological component construction.

[0062] At this point, a three-dimensional habitat structure is complete. This three-dimensional habitat structure is submerged in a selected area of ​​the wide valley and slow-flowing zone of the river, with the bottom ecological component 2, the middle ecological component 3, and the upper ecological component 4 located in the surface flow zone, main flow zone, and bottom flow zone of the selected area of ​​the wide valley and slow-flowing zone of the river, respectively. If multiple three-dimensional habitat structures need to be constructed, repeat steps 2.1-2.4 until all three-dimensional habitat structures are constructed, and the staged and stratified feeding grounds for the schizothorax fish are established.

[0063] By using a "gravity-based hanging / suspension + binding" connection method, the ecological components at each layer are firmly combined with the central main support component 1, forming a stable three-dimensional habitat structure with a tree-like spatial structure. The central main support component 1 not only utilizes the weight of the rocks to ensure the overall stability of the three-dimensional habitat structure, but also forms complex channels for fish passage. The gaps between the ecological components at each layer and the central main support component 1, as well as the porous structure of the net cage unit itself, together form natural water flow channels, promoting the gentle exchange of water and the transport of substances. This three-dimensional habitat structure enables the natural diffusion of prey organisms between different layers, supporting fish to move freely between the bottom shelter area, the middle foraging area, and the surface feeding area according to their physiological needs, forming a fully functional three-dimensional ecological channel network.

[0064] 3. Operation and Ecological Function Realization After the feeding area is installed, water flows naturally through the holes inside each cage unit and the gaps between the cage units.

[0065] Food supply: The upper layer of palm bark bundles 4012 provides edible microalgae for juvenile fish; the dormant eggs in the middle layer hatch within a few days, and zooplankton reproduce on the coconut fiber substrate, providing food for sub-adult fish; the bottom layer of slow-release organic matter blocks 2013 gradually releases nutrients, promotes biofilm growth and attracts benthic organisms, providing food for adult fish.

[0066] Ecological connectivity: Fish can safely migrate freely between the bottom sheltered area, the middle feeding area, and the upper feeding area through the porous network between the rocks inside the central main support component 1. Prey organisms and their larvae also naturally disperse between different layers of the system with the water flow.

[0067] Hydrological regulation: The symmetrical arrangement of the second net cage unit 301 in the middle disturbs the water flow, forming a slow-flow zone and micro-eddies around it, which is conducive to the aggregation of zooplankton and the grouping of sub-adult fish.

[0068] Maintenance and Management: The feeding area has low maintenance costs. The main task is to regularly (quarterly or semi-annually) check and replenish or replace the internal feed cultivation units (pre-cultivated palm bark bundles, loosely bound bodies filled with dormant eggs and coconut fiber, and slow-release organic matter blocks) according to the feed consumption, so as to continuously maintain the feed productivity of the system.

Claims

1. A staged and stratified feeding ground for schizothorax fish, characterized in that: One or more tree-shaped three-dimensional habitat structures are deployed in the slow-moving area of ​​the target water body. Each three-dimensional habitat structure is submerged in water. The three-dimensional habitat structure includes a central trunk support component, a bottom ecological component, an intermediate ecological component, and an upper ecological component. The central trunk support component is fixed to the bottom of the target water body by gravity. The bottom, intermediate, and upper ecological components are flexibly connected to the central trunk support component. The bottom, intermediate, and upper ecological components are located in the surface flow zone, main flow zone, and bottom zone of the slow-moving area of ​​the target water body, respectively. The bottom ecological component contains a bottom food cultivation unit to provide food for adult fish. The intermediate ecological component contains an intermediate food cultivation unit to provide food for sub-adult fish. The upper ecological component contains an upper food cultivation unit to provide food for juvenile fish. The central trunk support component, bottom ecological component, intermediate ecological component, and upper ecological component are all porous channel structures with different directions and interconnected with each other. The channels in the bottom, intermediate, and upper ecological components are connected to the channels in the central trunk support component.

2. The staged and stratified feeding ground for schizothorax fish according to claim 1, characterized in that: The central main support component includes a columnar gabion body, which is filled with irregular stones. The filling volume is 65%-85% of the volume of the gabion body. A large number of porous pores of different directions, sizes and interconnections are formed between the stones. The large number of interconnected porous pores constitute channels that run through all directions.

3. The staged and stratified feeding ground for schizothorax fish according to claim 1, characterized in that: The bottom layer ecological components, the middle layer ecological components, and the top layer ecological components do not come into contact with each other.

4. The staged and stratified feeding ground for schizothorax fish according to claim 1, characterized in that: The underlying ecological components include multiple first net cage units, each comprising a first net cage body filled with a bottom food cultivation unit. These first net cage units are evenly distributed circumferentially around a central main support component, and each first net cage unit is flexibly connected to the bottom of the central main support component. Each first net cage unit is placed on the bottom of the target water area. The intermediate ecological components include multiple second net cage units, each comprising a second net cage body filled with an intermediate food cultivation unit. These second net cage units are evenly distributed circumferentially around the central main support component, and each second net cage unit is flexibly connected to the central main support component. The upper ecological components include multiple third net cage units, each comprising a third net cage body filled with an upper food cultivation unit. These third net cage units are evenly distributed circumferentially around the central main support component, and each third net cage unit is flexibly connected to the central main support component. The mesh size of the first, second, and third net cage bodies decreases sequentially.

5. The staged and stratified feeding ground for schizothorax fish according to claim 4, characterized in that: The meshes at the top of each of the first, second, and third mesh cage units are respectively positioned and connected to the corresponding meshes on the central main support component by locking, and the first, second, and third mesh cage units are respectively fixedly connected to the corresponding meshes on the central main support component by binding.

6. The staged and stratified feeding ground for schizothorax fish according to claim 4, characterized in that: The volumes of the first, second, and third cage bodies decrease sequentially.

7. The staged and stratified feeding ground for schizothorax fish according to claim 4, characterized in that: There are four first mesh cage units, which are arranged in a cross shape. There are two second mesh cage units, which are arranged symmetrically about the central main support member. There are two third mesh cage units, which are arranged symmetrically about the central main support member. The second and third mesh cage units are staggered in the vertical direction.

8. The staged and stratified feeding ground for schizothorax fish according to claim 7, characterized in that: The first gabion body is rectangular, the first gabion unit is cubic, and the second and third gabion units are both regular prisms.

9. The staged and stratified feeding ground for schizothorax fish according to claim 1, characterized in that: The bottom layer of the food cultivation unit is a mixture of coarse gravel and slow-release organic matter blocks. The middle layer of the food cultivation unit includes multiple loosely bundled bodies formed by binding plant stems. The interior and surface of each loosely bundled body are filled with a granular mixture of cladoceran dormant eggs and natural plant fibers. The middle layer of the food cultivation unit includes multiple palm bark bundles made of palm bark. The palm bark bundles have a broom-like structure or a curtain-like structure. The surface of the palm bark bundles is covered with a high density of microalgae communities.

10. A method for constructing a staged and stratified feeding ground for schizothorax fish as described in claim 1, characterized in that... Includes the following steps: S1, prefabricated central main support components, first wire mesh cage unit, second wire mesh cage unit and third wire mesh cage unit; S2. Determine the target water area, level the bottom of the area with slower water flow, and then place the central main support component on the bottom of the selected location in the area with slower water flow. S3. Distribute multiple first net cage units evenly around the central main support component, and "sit" each first net cage unit at the corresponding position at the bottom of the central main support component, so that the bottom of each first net cage unit is close to the bottom of the selected position in the area where the water flow in the target water is relatively slow. The construction of the bottom ecological component is completed. S4. Distribute multiple second cage units evenly around the central main support component, and suspend each second cage unit at the corresponding position in the middle of the central main support component. The construction of the intermediate layer ecological component is completed. S5. Distribute multiple third mesh cage units evenly around the central main support component, and suspend each third mesh cage unit at the corresponding position on the central main support component. The upper ecological component is now complete. S6. At this point, a three-dimensional habitat structure component is completed. The three-dimensional habitat structure is submerged in the area of ​​the target water body where the water flow is relatively slow. The bottom ecological component, the middle ecological component, and the upper ecological component are located in the surface flow area, the main flow area, and the bottom area of ​​the area where the water flow is relatively slow, respectively. If multiple three-dimensional habitat structures need to be constructed, repeat steps S2-S5 until all three-dimensional habitat structures are constructed and the staged and layered feeding grounds for schizothorax fish are created.

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