Cold region pond high-yield carp and crayfish polyculture system

Abstract

The invention discloses a high-yield carp and crayfish polyculture system in a cold region pond, relates to the high-yield carp and crayfish polyculture system in the cold region pond, and belongs to the field of biological behavior ecology and the technical field of aquaculture. The invention aims to break through the ecological constraint of the special habitat of the cold region on the crayfish and solve the problem of the economic benefit bottleneck of the main culture pond for the carps in the cold region. The system comprises a carp feeding area, an annular submerged plant zone and a main crayfish breeding area, and the area ratio of the carp feeding area to the annular submerged plant zone to the main crayfish breeding area is (1-1.5): (0.5-1.0): (10.5-9.5). According to the method, the economic benefit bottleneck of the carp main culture pond is solved, the survival trapping of the crayfish is broken through, and the ecological constraint brought by the special habitat of the cold region is tamed.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, specifically to a high-yield carp and crayfish polyculture system in cold-region ponds. Background Technology

[0002] In my country's cold regions, carp has long been a staple fish in pond aquaculture, but it has faced severe ecological bottlenecks for many years: feed costs account for over 60% of total aquaculture costs, and price fluctuations have kept average profits per mu (a Chinese unit of area, approximately 0.165 acres) below 2,000 yuan for many consecutive years. Meanwhile, crayfish farming in cold regions, as a new direction for local industrial upgrading, is still in the exploratory stage—farmers generally adopt the "high-feeding-dense stocking" model common in southern regions to combat insufficient accumulated temperature, leading to a double crisis: on the one hand, excessive fermented feed settles to the bottom (the microbial activity in cold-region waters is only 1 / 4 that in the south), forming a pollution layer, causing a sharp increase in metabolic losses and a decline in crayfish quality; on the other hand, due to the special cold-region pond habitat, over-reliance on artificial feeding makes feed costs far higher than the normal 30%-40% in the south. How to utilize the complementary ecological niches of carp and crayfish to construct a polyculture model is an effective way to achieve efficient utilization of carp farming ponds in cold regions. Summary of the Invention

[0003] The purpose of this invention is to overcome the ecological constraints of special cold-region habitats on crayfish, solve the technical problem of economic efficiency bottleneck in cold-region carp-dominated ponds, and provide a high-yield carp-crayfish polyculture system for cold-region ponds.

[0004] The high-yield carp-crayfish polyculture system in cold-region ponds includes a carp feeding area, a ring-shaped submerged plant zone, and a crayfish main culture area, with the area ratio of the carp feeding area, the ring-shaped submerged plant zone, and the crayfish main culture area being (1-1.5): (0.5-1.0): (10.5-9.5).

[0005] The carp feeding area is a circular body of water with a diameter of 8.4±0.3m. The carp feeding area extends outwards and is successively set up with a gentle slope area, a steep slope area and a crayfish main breeding area. The ring-shaped submerged plant belt is located at the junction of the gentle slope area and the steep slope area.

[0006] The average depth of the carp feeding area is 1.8m; the slope ratio of the gentle slope area is 1:10-1:20; the average depth of the ring-shaped submerged plant zone is 1.2m; the slope ratio of the steep slope area is 1:1.2-1:5; and the depth of the crayfish main farming area is 0.8m.

[0007] The bottom of the carp feeding area is covered with a 3-meter square corrugated net with a sine wave peak and trough structure with a wave height of 15±1cm and a wavelength of 50cm.

[0008] The proportion of submerged plant areas increases dynamically with the number of days of cultivation, and the rate of increase meets the following conditions: when the number of days of cultivation is ≤30, the proportion is 5.0% of the baseline area; from 30 to 90 days, the daily increase is 0.04-0.06%; and after 90 days, the increase is ≤0.03%.

[0009] The bottom of the main crayfish farming area has a 20cm thick layer of flat silt, and palm-fiber shrimp nests (simulating natural shrimp burrows) with a 3cm aperture are provided on the flat silt layer.

[0010] Furthermore, the area ratio of the carp feeding area, the submerged plant zone, and the crayfish main farming area is 1:1:10.

[0011] Furthermore, 100 palm-shaped shrimp nests are placed per acre.

[0012] Furthermore, the ring-shaped submerged plant belt consists of 60% core water purification functional species and 40% auxiliary ecological species, with a row spacing of 40cm. The core water purification functional species are one or two of Potamogeton pectinatus, Potamogeton bamboois, and Potamogeton malaianus, and the auxiliary ecological species are one or two of Hydrilla verticillata, Ceratophyllum demersum, and Myriophyllum spicatum.

[0013] Furthermore, under the condition of water temperature of 4-6℃ in the early stage of ice melting, transplant the ring-shaped submerged plant strips with plant buds and rhizomes, and prune regularly to maintain the plant strip coverage of 60%-70%.

[0014] Furthermore, the submerged annular plant strip adopts a three-dimensional configuration pattern, with Potamogeton pectinatus and Potamogeton bambooe accounting for 60% of the submerged plant strip as the main framework, Hydrilla verticillata accounting for 30% of the submerged plant strip as the three-dimensional filling, and Ceratophyllum demersum dynamically supplementing the submerged plant strip as the 10% of the submerged plant strip, and the row spacing of the submerged plant strip is 40cm;

[0015] Under the condition of water temperature of 4-6℃ in the early stage of ice melting, transplant the ring-shaped submerged plant strip with plant buds and rhizomes, and prune regularly to maintain the plant strip coverage of 60%-70%.

[0016] Furthermore, the ring-shaped submerged plant belt consists of *Potamogeton crispus* and *Hydrilla verticillata*, with a row spacing of 40 cm.

[0017] Furthermore, the *Potamogeton crispus* is *Potamogeton pectinatus*, *Potamogeton bambusoides*, or *Potamogeton malaianus*.

[0018] Furthermore, the density of the ring-shaped submerged plants is 5 clumps / m², and the plant height is ≤50cm.

[0019] Furthermore, a PE net is installed on the side of the annular submerged plant belt adjacent to the carp feeding area.

[0020] This invention employs a gradient transition design:

[0021] Carp feeding area (water depth 1.8m) → Circular submerged plant zone (water depth 1.2m) → Crayfish main farming area (water depth 0.8m)

[0022] (1) Carp feeding area:

[0023] Location and Depth: Located in the relatively central area of ​​the pond. The depth of -1.8m is designed to take advantage of the stable low temperature at the bottom of cold-water bodies; it is the main feeding area for carp.

[0024] Function: Large amounts of uneaten food and fish feces accumulate here.

[0025] (2) Circular submerged plant zone:

[0026] Core functions: Hydraulic gradient drives material transport and enables biological interception and nutrient conversion. It releases oxygen, which is produced through photosynthesis, improving dissolved oxygen levels in the area. It also prevents invasive species, effectively blocking carp (especially larger ones) from easily entering crayfish farming areas.

[0027] Guiding water flow: The water flow (similar to a "gentle push") created by carp feeding and swimming in groups in the feeding area will move up the slope.

[0028] Transport of materials: This water flow will push the accumulated, incompletely decomposed fine particulate organic matter (SS), dissolved nutrients (N, P), and suspended bottom sulfides (when disturbance occurs) from the feeding area onto the slope.

[0029] Location and Depth: The average depth of -1.2m is shallower than the carp feeding area but deeper than the crayfish main farming area. This water depth ensures that most submerged plants have the light required for normal growth while also receiving nutrients transported from the carp feeding area.

[0030] High-efficiency "filter bed": densely planted with submerged plants that are adapted to low temperatures and have strong water purification capabilities.

[0031] The gentle slopes in the gentle slope areas are flat or even nearly level, which slows down the water flow. This reduced flow velocity allows suspended nutrients and fine particles to settle and be absorbed by the roots, stems, and leaves of plants. The plants directly utilize dissolved nitrogen and phosphorus for growth. By absorbing pollutants, the plants significantly reduce the nitrogen and phosphorus content in the water, decreasing the pollutant load entering the shrimp-growing area and improving water quality.

[0032] In the steep slope area, the gradient suddenly increases. This creates physical separation and energy blockage. As water flows from the gentle slope area into the steep slope area, the rapid increase in gradient alters the flow direction, drastically reduces the flow velocity, and drastically decreases the carrying capacity. The steep slope forms a distinct interface, significantly limiting the possibility of larger or more sedimentary materials (mainly relatively clean residues processed by plants) being washed away and diffused back into the crayfish farming area. This ensures that water and materials are primarily transported and processed within the pathway of "carp feeding area → ring-shaped submerged plant zone."

[0033] (3) Main crayfish farming area:

[0034] Location and depth: Located above the steep slope area, in the shallowest area (average water depth 0.8m).

[0035] Function: Provides optimal habitat for crayfish.

[0036] Isolation and stability: It is far from the pollution source of high-intensity feeding (carp feeding area). Physical and energy isolation is achieved through steep slopes.

[0037] High-quality substrate: It accepts a small amount of relatively clean and fine organic debris that settles from the treatment area (ring-shaped submerged plant zone) (which can serve as part of the crayfish's natural food); the bottom mud has the lowest level of pollution.

[0038] Suitable water depth and dissolved oxygen: -0.8m is a shallower bottom area with a slightly higher temperature than the deepest part (especially after solar radiation), which is conducive to crayfish inhabiting and burrowing. Due to the effective interception and purification of pollutants by plants, combined with the natural convection exchange brought about by the possible midday warming of shallow water, this area can maintain relatively better (not the highest, but safer for crayfish and closer to the bottom) bottom dissolved oxygen and water quality stability.

[0039] Light and natural food: Shallower light also promotes the growth of some attached algae and small benthic organisms, providing supplementary natural food.

[0040] The core water purification species in the ring-shaped submerged plant belt:

[0041] (1) Potamogeton pectinatus:

[0042] Key advantages:

[0043] Extremely cold-resistant: Dormant buds (winter buds) can overwinter in mud at -1℃ to 4℃ under ice, and will sprout when the water temperature is >5℃.

[0044] High turbidity adaptation: Feathered, finely lobed blades effectively intercept suspended particles, significantly improving water transparency.

[0045] Rapid propagation: It has an extremely strong ability to regenerate from broken branches, and a single plant can multiply more than 10 times in a year.

[0046] Functional positioning: the main force in physical interception of suspended solids, and the core species for water clarification.

[0047] (2) Potamogeton wrightii:

[0048] Key advantages:

[0049] Low temperature growth: Photosynthesis starts at 6℃ and reaches its peak growth at 15℃ (which coincides with the short growth period in Northeast China).

[0050] Heavy metal adsorption: Leaf secretions can chelate ions such as lead and cadmium in the sediment, reducing environmental toxicity.

[0051] Carbon sequestration capacity: The plant has a high degree of lignification and decomposes slowly after settling to the bottom of the water (carbon sequestration > carbon release).

[0052] Functional positioning: core species for water purification and bottom sediment stabilization.

[0053] (3) Potamogeton malaianus:

[0054] Key advantages:

[0055] Shade-resistant: Adaptable to extremely low light environments with light transmittance of <5% during periods of ice cover.

[0056] Nutritional competition: Highly efficient absorption of nitrates (daily absorption rate > 1.2 mg / L·m²), inhibiting algal blooms.

[0057] Functional positioning: Key species for water quality maintenance during the ice-covered period.

[0058] Assisted ecological species

[0059] (1) *Hydrilla verticillata* (a domesticated variant from Northeast China):

[0060] Selectively cultivated cold-resistant varieties (such as "Songhei No. 1") can continue to grow at 10℃, and adventitious roots grow on the stem nodes to enhance the substrate retention capacity.

[0061] Community construction: A three-dimensional configuration mode was adopted, with "Platycodon grandiflorus + Potamogeton crispus" (60%) as the main framework, "Hydrilla verticillata" (30%) as the three-dimensional filling, and "Ceratophyllum demersum" (10%) as the dynamic supplement.

[0062] Transplanting timing: Transplant with buds and rhizomes during the early stage of ice melting (water temperature 4~6℃), when low temperature stress is low and the peak activity of fish and shrimp is avoided.

[0063] Space management: Regularly prune to maintain plant coverage of 60%~70%, ensure effective water circulation at the bottom layer, and avoid the formation of local anaerobic zones.

[0064] 2) Ceratophyllum demersum:

[0065] Planktonic characteristics: Rootless plants, floating in the upper and middle layers of the water.

[0066] Functional value: Rapidly absorbs ammonia nitrogen (removal rate >70% in 72h), providing a natural protective substrate for shrimp larvae.

[0067] Limitations: It withers completely in winter and needs to be replanted in spring; it is best suited for seasonal replanting.

[0068] (3) Myriophyllum spicatum:

[0069] Special function: It secretes algae-inhibiting allelochemicals (such as tannic acid) to inhibit cyanobacterial blooms.

[0070] Note: Coverage must be strictly controlled to be less than 15% to avoid excessive spread and competition for sunlight.

[0071] This invention aims to address the economic bottleneck in carp-farming ponds, overcome the survival challenges of crayfish, and tame the ecological constraints imposed by the unique cold-climate habitat. The corrugated net increases feed accessibility by 42% and reduces the need for crayfish to swim.

[0072] The core breakthrough of this invention lies in the fact that the cold and low-temperature environment is actually conducive to establishing the spatial memory of carp feeding behavior. Based on this, the ecological niche precision separation technology has been developed for the first time to realize the production of bait by utilizing fish behavior without drug intervention, creating endogenous nutrient supply in the system, which can significantly improve the live bait substitution rate. At the same time, the carp's uneaten bait can be converted by crayfish through the chain nutrient cycle established by the system.

[0073] Effects of this invention:

[0074] Targeted pollution control: Potential pollutants generated by carp activity (uneaten feed, feces, and disturbed suspended matter) are efficiently intercepted, collected, and guided to the treatment area (ring-shaped submerged plant zone), rather than settling and anaerobic decomposing in the main crayfish farming area.

[0075] The nutrients contained in the pollutants are absorbed and utilized by the ring-shaped submerged plants, and converted into plant biomass (which can be used as green fodder or raw material for subsequent fermentation).

[0076] Habitat isolation: Clear physical separation (steep slope + water depth difference) ensures that the crayfish habitat is not excessively disturbed by carp.

[0077] Water quality optimization in crayfish farming areas: The treated clean water and a small amount of fine organic matter are introduced into the main crayfish farming area, providing a better growth environment for the crayfish.

[0078] Enhance natural water circulation: By cleverly utilizing water flow dynamics and gravity settling, the system can be driven naturally by minimizing external energy input (such as water pumps).

[0079] This invention's gradient transition design utilizes the artificial topography at the bottom of the pond to simulate and enhance a natural water cycle path conducive to the directional transfer, transformation, and functional zoning of pollution. It is a concrete engineering embodiment of the "precise separation of time, space, and location" concept in the spatial dimension. This design achieves spatial barrier, preventing carp from entering the shallow shrimp area; shrimp passage: palm fiber mats are laid along the slope for crayfish to travel back and forth to feed; energy transfer: the nutrient-rich water generated by the carp's disturbance flows by gravity into the submerged plant zone.

[0080] This invention does not define "prohibited areas," but rather creates "high-welfare areas that carp are unwilling to leave" + "convenient channels for crayfish to actively forage for food," thereby achieving precise separation of ecological niches. Detailed Implementation

[0081] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0082] Specific implementation method one: This implementation method of high-yield carp and crayfish polyculture system in cold-region ponds includes a carp feeding area, a ring-shaped submerged plant belt and a crayfish main culture area, and the area ratio of the carp feeding area, the ring-shaped submerged plant belt and the crayfish main culture area is (1-1.5) : (0.5-1.0) : (10.5-9.5);

[0083] The carp feeding area is a circular body of water with a diameter of 8.4±0.3m. The carp feeding area extends outwards and is successively set up with a gentle slope area, a steep slope area and a crayfish main breeding area. The ring-shaped submerged plant belt is located at the junction of the gentle slope area and the steep slope area.

[0084] The average depth of the carp feeding area is 1.8m; the slope ratio of the gentle slope area is 1:10-1:20; the average depth of the ring-shaped submerged plant zone is 1.2m; the slope ratio of the steep slope area is 1:1.2-1:5; and the depth of the crayfish main farming area is 0.8m.

[0085] The bottom of the carp feeding area is covered with a 3-meter square corrugated net with a sine wave peak and trough structure with a wave height of 15±1cm and a wavelength of 50cm.

[0086] The proportion of submerged plant areas increases dynamically with the number of days of cultivation, and the rate of increase meets the following conditions: when the number of days of cultivation is ≤30, the proportion is 5.0% of the baseline area; from 30 to 90 days, the daily increase is 0.04-0.06%; and after 90 days, the increase is ≤0.03%.

[0087] The bottom of the main crayfish farming area has a 20cm thick layer of flat silt, and palm-fiber shrimp nests (simulating natural shrimp burrows) with a 3cm aperture are provided on the flat silt layer.

[0088] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the area ratio of the carp feeding area, the submerged plant zone, and the crayfish main farming area is 1:1:10. Everything else is the same as in Specific Implementation Method One.

[0089] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that 100 palm leaf shrimp nests are placed per acre. Everything else is the same as Specific Implementation Method One or Two.

[0090] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One through Three in that...

[0091] The ring-shaped submerged plant belt consists of 60% core water purification functional species and 40% auxiliary ecological species, with a row spacing of 40cm. The core water purification functional species are one or two of Potamogeton pectinatus, Potamogeton bamboois, and Potamogeton malaianus. The auxiliary ecological species are one or two of Hydrilla verticillata, Ceratophyllum demersum, and Myriophyllum spicatum.

[0092] Under the condition of water temperature of 4-6℃ at the beginning of ice melting, transplant the ring-shaped submerged plant strip with plant buds and rhizomes, and prune regularly to maintain the plant strip coverage of 60%-70%. Other aspects are the same as in one of the specific implementation methods one to three.

[0093] When the core water purification function is a composition, the proportions of the components can be arbitrary.

[0094] When the auxiliary ecological species is a composition, the proportions of the components are arbitrary.

[0095] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One through Four in that...

[0096] The submerged ring of plants adopts a three-dimensional configuration pattern with Potamogeton pectinatus and Potamogeton bambooe as the main framework, accounting for 60% of the plants in the submerged ring, Hydrilla verticillata as the three-dimensional filling, and Ceratophyllum demersum as the dynamic supplement, accounting for 10% of the plants in the submerged ring. The row spacing of the submerged ring plants is 40cm.

[0097] Under the condition of water temperature of 4-6℃ at the beginning of ice melting, transplant the ring-shaped submerged plant strip with plant buds and rhizomes, and prune regularly to maintain the plant strip coverage of 60%-70%. Other aspects are the same as in one of the specific implementation methods one to four.

[0098] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the ring-shaped submerged plant strip is composed of *Potamogeton crispus* and *Hydrilla verticillata*, with a row spacing of 40 cm. Everything else is the same as in Specific Implementation Methods One to Five.

[0099] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that the *Potamogeton crispus* is *Potamogeton pectinatus*, *Potamogeton bambusoides*, or *Potamogeton malaianus*. Everything else is the same as in Specific Implementation Method Six.

[0100] The ratio of *Potamogeton crispus* and *Hydrilla verticillata* is arbitrary.

[0101] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the density of the ring-shaped submerged plants is 5 clumps / m², and the plant height is ≤50cm. Everything else is the same as in Specific Implementation Methods One to Seven.

[0102] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that a PE net is provided on the side of the annular submerged plant strip adjacent to the carp feeding area. Otherwise, it is the same as Specific Implementation Methods One to Eight.

[0103] The following experiments were used to verify the effectiveness of the invention:

[0104] Experiment 1:

[0105] High-yield carp and crayfish polyculture system in cold-region ponds:

[0106] The high-yield carp and crayfish polyculture system in cold-region ponds includes a carp feeding area, a ring-shaped submerged plant zone, and a crayfish main culture area, with the area ratio of the carp feeding area, the ring-shaped submerged plant zone, and the crayfish main culture area being 1:1:10.

[0107] Table 1

[0108]

[0109] The carp feeding area is a circular body of water with a diameter of 8.4m, surrounded by a ring of submerged plants. The average depth of the carp feeding area is 1.8m. The slope ratio of the gentle slope area is 1:10. The average depth of the ring of submerged plants is 1.2m. The slope ratio of the steep slope area is 1:1.2. The depth of the crayfish main farming area is 0.8m. The ring of submerged plants is located at the boundary between the gentle slope area and the steep slope area.

[0110] The bottom of the carp feeding area is covered with a 3-meter square corrugated net (which increases the accessibility of bait by 42% and reduces the need for swimming). The corrugated net has a sine wave peak and trough structure with a wave height of 15±1cm and a wavelength of 50cm. A PE net is set up on the side of the ring-shaped submerged plant belt adjacent to the carp feeding area.

[0111] The proportion of submerged plant areas increases dynamically with the number of days of cultivation, and the rate of increase meets the following conditions: when the number of days of cultivation is ≤30, the proportion is 5.0% of the baseline area; from 30 to 90 days, the daily increase is 0.04-0.06%; and after 90 days, the increase is ≤0.03%.

[0112] The bottom of the main crayfish farming area has a 20cm thick layer of flat silt, and palm leaf crayfish nests (simulating natural crayfish burrows) with a 3cm aperture are provided on the flat silt layer.

[0113] In early April, when the water temperature was 4-6℃ during the initial ice melt, submerged ring-shaped plant strips with buds and rhizomes were transplanted. Regular pruning was maintained to ensure the plant strips covered 60%-70% of the area. Once the water temperature stabilized at ≥12℃, carp were introduced into the carp feeding area at a stocking rate of 800 carp per acre (stocking with 200g of spring feed). (95.7% of the carp population remained within 30m of the feeding area). Artificial feed (Tongwei 181-29 type fish feed) was provided at fixed times (6:00, 10:30, 15:00, 18:30, and 21:00) for 21 days, successfully establishing a "feeding behavior-spatial anchoring reflex" in the carp population. Increasing the frequency helps improve domestication efficiency. Then, feed 5 times a day. In mid-May, release 5g shrimp fry at a rate of 4500 shrimp / mu. The coverage of submerged plants reaches 30%. In early July, reduce the feed to 1.8% of body weight and start round-harvesting individuals >35g. Maintain dissolved oxygen above 7mg / L in the ring of submerged plants. By the end of September, carp reach market weight (>800g). Clean the pond and harvest the remaining shrimp. The total breeding cycle is ≤160 days.

[0114] The average weight of carp harvested from the pond was 815g.

[0115] The crayfish weighed an average of 42g upon harvest.

[0116] The proportion of live bait replacing artificial feed reached 38.7%. Underwater video recording for 72 consecutive hours showed that the maximum dispersion radius of the carp school in the feeding area was 4.17m (less than the design safety boundary). Under the condition of feeding the carp at fixed points ≥ 5 times a day, the activity range of the carp never exceeded 3m from the edge of the feeding area, and no behavior was found to enter the main shrimp farming area.

[0117] The principle of carp activity area locking: biological behavior control (non-physical forced confinement), high feeding frequency, carp gathering at fixed points, wavy substrate to improve feeding efficiency, submerged plant barriers, and reduced carp's willingness to explore.

[0118] Carp complete more than 90% of their life activities in the feeding area (a circular body of water with a diameter of 8.4m), achieving a behavioral trapping effect through environmental factor regulation.

[0119] Dynamic ratio comparison of carp and crayfish:

[0120] Table 2

[0121]

[0122] Table 3. Selection of submerged plants and community construction in the annular submerged plant zone.

[0123]

[0124] The ring-shaped submerged plant belt, through its tiered configuration and refined spatial structure control, achieves an ecological cascade effect of "efficiently intercepting suspended solids → directionally converting nutrients → stabilizing the bottom microenvironment" under low-temperature conditions. It is the cornerstone of sustainable water quality management in the carp-crayfish co-culture system.

Claims

1. A high-yield carp-crayfish polyculture system for cold-region ponds, characterized in that... The high-yield carp-crayfish polyculture system in cold-region ponds includes a carp feeding area, a ring-shaped submerged plant zone, and a crayfish main culture area, with the area ratio of the carp feeding area, the ring-shaped submerged plant zone, and the crayfish main culture area being (1-1.5): (0.5-1.0): (10.5-9.5). The carp feeding area is a circular body of water with a diameter of 8.4±0.3m. The carp feeding area extends outwards and is successively set up with a gentle slope area, a steep slope area and a crayfish main breeding area. The ring-shaped submerged plant belt is located at the junction of the gentle slope area and the steep slope area. The average depth of the carp feeding area is 1.8m; the slope ratio of the gentle slope area is 1:10-1:20; the average depth of the ring-shaped submerged plant zone is 1.2m; the slope ratio of the steep slope area is 1:1.2-1:5; and the depth of the crayfish main farming area is 0.8m. The bottom of the carp feeding area is covered with a 3-meter square corrugated net with a sine wave peak and trough structure with a wave height of 15±1cm and a wavelength of 50cm. The proportion of the annular submerged plant zone increases dynamically with the number of days of cultivation, and the rate of increase meets the following conditions: when the number of days of cultivation is ≤30, the proportion is 5.0% of the baseline area; the daily increase is 0.04-0.06% during the period of 30-90 days; and the increase is ≤0.03% after 90 days. The bottom of the main crayfish farming area has a 20cm thick layer of flat-bottomed silt, and palm-fiber crayfish nests with a 3cm aperture are provided on the flat-bottomed silt layer.

2. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 1, characterized in that... The area ratio of the carp feeding area, the submerged plant zone, and the crayfish main farming area is 1:1:

10.

3. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 1, characterized in that... The palm-shaped shrimp nests are placed at a rate of 100 per acre.

4. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 1, characterized in that... The ring-shaped submerged plant belt consists of 60% core water purification functional species and 40% auxiliary ecological species, with a row spacing of 40cm. The core water purification functional species are one or two of Potamogeton pectinatus, Potamogeton bamboois, and Potamogeton malaianus. The auxiliary ecological species are one or two of Hydrilla verticillata, Ceratophyllum demersum, and Myriophyllum spicatum. Under the condition of water temperature of 4-6℃ in the early stage of ice melting, transplant the ring-shaped submerged plant strip with plant buds and rhizomes, and prune regularly to maintain the plant strip coverage of 60%-70%.

5. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 1, characterized in that... The submerged ring of plants adopts a three-dimensional configuration pattern with Potamogeton pectinatus and Potamogeton bambooe as the main framework, accounting for 60% of the plants in the submerged ring, Hydrilla verticillata as the three-dimensional filling, and Ceratophyllum demersum as the dynamic supplement, accounting for 10% of the plants in the submerged ring. The row spacing of the submerged ring plants is 40cm. Under the condition of water temperature of 4-6℃ in the early stage of ice melting, transplant the ring-shaped submerged plant strip with plant buds and rhizomes, and prune regularly to maintain the plant strip coverage of 60%-70%.

6. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 1, characterized in that... The ring-shaped submerged plant belt consists of *Potamogeton crispus* and *Hydrilla verticillata*, with a row spacing of 40 cm.

7. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 6, characterized in that... The pondweed in question is Potamogeton crispus, Potamogeton salsa, or Potamogeton malaianus.

8. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 1, characterized in that... The density of the ring-shaped submerged plants is 5 clumps / m², and the plant height is ≤50cm.

9. The high-yield carp-crayfish polyculture system in cold-region ponds according to claim 1, characterized in that... A PE net is installed on the side of the ring-shaped submerged plant belt adjacent to the carp feeding area.

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