Ecocoupled aquaculture system and method

Abstract

The application discloses an ecological coupling breeding system and method, and relates to the technical field of aquaculture and ecological restoration. The system is arranged in an intertidal zone with tide exchange conditions. In the system, a mangrove belt module is planted on the bank of a dam of a breeding pond to form a mangrove belt; a mangrove planting island module is arranged in the interior of the breeding pond and is planted with mangrove plants; a tidal creek network module is connected with the breeding pond and the open sea and is used for water body regulation through tide exchange; a blue crab breeding area module is arranged at least one of the root distribution area of the mangrove planting island module, the two sides of the tidal creek network module and the root area of the mangrove belt module; a shellfish cultivation area module is arranged at least one of the bottom of the tidal creek network, the root attachment area of the mangrove plants and the bottom area of the breeding pond; and a seaweed breeding area module is arranged on the surface and the middle and lower layers of the water body of the breeding pond. The application constructs a four-trophic-level compound ecological system through cooperation of the modules.

Description

Technical Field

[0001] This invention relates to the field of aquaculture and ecological restoration technology, and in particular to an ecologically coupled aquaculture system and method. Background Technology

[0002] Mangroves are woody plant communities that grow in the intertidal zone of tropical and subtropical coasts and are periodically submerged by seawater. They play important ecological functions such as wind and wave protection, shoreline stabilization, carbon sequestration, and maintaining biodiversity. However, large-scale aquaculture and land reclamation in the past have severely squeezed the living space of mangroves, leading to ecological degradation. How to protect the mangrove ecosystem while ensuring the economic benefits of aquaculture has become an urgent technical challenge.

[0003] Currently, some technical solutions involving the coupling of mangroves and aquaculture have been proposed. For example, by configuring mangrove plants and aquatic animals in aquaculture ponds and regulating water levels, both mangrove protection and aquaculture can be achieved; or by constructing planting islands in the middle of aquaculture ponds to plant mangrove plants, and combining them with aquatic plants and large algae for mud crab farming.

[0004] However, the current aquaculture schemes mentioned above still have shortcomings. First, the system components are limited in level, mostly remaining at the binary or ternary combination level, failing to systematically integrate the functions of multiple trophic levels. Second, there is a lack of proactive design for material cycling and energy utilization within the system, and the components have not formed a closed positive feedback loop. Third, the spatial layout is relatively extensive, with strong reliance on mechanical aeration and high operation and maintenance costs. Fourth, the survival rate of mud crab farming still needs to be further improved.

[0005] Therefore, the present invention provides an ecologically coupled aquaculture system and aquaculture method thereof, aiming to solve one or more technical problems in the above-mentioned aquaculture scheme. Summary of the Invention

[0006] The main objective of this invention is to propose an ecologically coupled aquaculture system and method, which aims to solve one or more technical problems in the above-mentioned aquaculture schemes.

[0007] To achieve the above objectives, the present invention proposes an ecologically coupled aquaculture system, which is deployed in the intertidal zone with tidal exchange conditions. The ecologically coupled aquaculture system includes: Mangrove belt modules are planted along the banks of the embankments of aquaculture ponds to form a continuous mangrove belt, which is used to stabilize the soil and protect the embankments, forming an ecological barrier and providing a source of litter for the aquaculture ponds; Mangrove planting island module, set in the internal area of ​​aquaculture pond, with mangrove plants planted on the mangrove planting island module; The tidal channel network module connects aquaculture ponds with the open sea and is used to regulate water quality through tidal exchange; The mud crab farming area module is located in at least one of the root distribution areas of the mangrove planting island module, both sides of the tidal channel network module, and the root area of ​​the mangrove belt module, and is used for releasing mud crabs. A shellfish rearing module, located at least one of the following locations: the bottom of a tidal channel network, the root attachment area of ​​mangrove plants, and the bottom area of ​​a rearing pond, for the rearing of filter-feeding shellfish; and The seaweed cultivation module is set on the surface and lower layers of the water in the cultivation pond for the cultivation of large seaweed.

[0008] In one embodiment, the seaweed aquaculture zone module includes a floating seaweed layer on the water surface and a suspended seaweed layer underwater. The floating seaweed layer covers 20%-40% of the water area of ​​the aquaculture pond, and the suspended seaweed layer covers 15%-30% of the water volume. And / or, the floating seaweed layer is used for shading and primary dissolved oxygen supply during the day, and the suspended seaweed layer is used for water oxygenation and nitrogen and phosphorus absorption, forming a dissolved oxygen distribution in the vertical direction of the aquaculture water.

[0009] In one embodiment, the larvae of filter-feeding shellfish cultivated in the shellfish cultivation area module serve as natural food for mud crabs in the mud crab farming area module; the organic debris formed by the decomposition of litter from the mangrove belt module by microorganisms serves as food for the filter-feeding shellfish.

[0010] In one embodiment, in the spatial layout of the ecologically coupled aquaculture system, the mangrove belt module accounts for 10%-20% of the total system area, the mangrove planting island module accounts for 5%-15% of the total system area, the tidal channel network module accounts for 10%-20% of the total system area, the mud crab farming area module accounts for 20%-40% of the total system area, and the shellfish cultivation area module accounts for 15%-20% of the total system area.

[0011] In one embodiment, the planting density of mangrove plants on the mangrove planting island module is 1-5 plants per square meter; the tidal channel network module includes a main tidal channel and branch tidal channels, the width of the tidal channels is 1-5m and the depth is 0.5-2m, and the tidal channel network module is equipped with gates to control the exchange of water with the open sea.

[0012] This invention also proposes an ecologically coupled aquaculture method, which uses the above-mentioned ecologically coupled aquaculture system for ecologically coupled aquaculture. The method includes the following steps: Construct or modify aquaculture ponds in selected intertidal areas and divide them into modular functional zones to form mangrove belt modules, mangrove planting island modules, tidal channel network modules, mud crab aquaculture area modules, shellfish cultivation area modules, and seaweed aquaculture area modules. Mangrove plants are planted in the mangrove belt module and the mangrove planting island module to form an ecological barrier; Shellfish seedlings are introduced into the shellfish cultivation area module, and large seaweeds are introduced into the seaweed cultivation area module. Crab seedlings are released into the crab farming area module, and the crabs feed on the shellfish as natural food. During the breeding period, the system operates in a coordinated closed loop, forming a material cycle chain, an energy utilization chain, and an economic value chain, and regulates the breeding environment parameters. After the aquaculture is completed, the mud crabs are harvested, the large seaweed and shellfish are collected, and the carbon sequestration of the mangrove plants is calculated and evaluated.

[0013] In one embodiment, the step of regulating the aquaculture environment parameters includes: The dissolved oxygen content in the aquaculture pond should be controlled at no less than 4.0 mg / L, the salinity should be controlled at 15-30 ppt, and the water temperature should be controlled at 20-33℃. The water level in the pond is controlled within 10-30 cm above the average elevation of the mangrove planting island module, and the aerial roots and breathing roots of the mangrove plants are intermittently exposed above the water surface.

[0014] In one embodiment, the material cycle is as follows: nutrients in the excrement and uneaten food of mud crabs are absorbed and utilized by mangrove plants; after the dead branches and leaves of mangrove plants fall into the water, they are decomposed by microorganisms and transformed into natural food for shellfish, which are then consumed by mud crabs.

[0015] In one embodiment, the energy utilization chain is as follows: large seaweed releases oxygen through photosynthesis to increase the dissolved oxygen content in the water, meeting the oxygen consumption needs of mangrove roots and blue crabs and shellfish, and reducing the use of mechanical aeration equipment.

[0016] In one embodiment, the economic value chain is as follows: mud crabs are the main economic product for generating aquaculture revenue; carbon sinks of mangrove plants are monetized through carbon trading or carbon credits; and large seaweed and shellfish are harvested and sold as secondary economic products.

[0017] The technical solution of this invention involves planting mangrove belt modules along the banks of aquaculture ponds, forming a continuous mangrove belt. Due to the extensive root network of mangrove plants, this network can stabilize the soil and protect the embankment, thus creating an ecological barrier along the embankment. This effectively reduces the risk of embankment erosion by sea waves and decreases the periodic reinforcement and maintenance costs. Simultaneously, the litter from the mangrove belt modules enters the aquaculture water through tidal action and natural sedimentation. After decomposition by microorganisms, it becomes an important source of organic debris within the aquaculture system, providing a natural food base for subsequent shellfish cultivation, achieving a synergy between the ecological barrier function and the food production function.

[0018] By setting up mangrove planting island modules within the aquaculture pond and planting mangrove plants on these modules, the mangrove root systems create a staggered, three-dimensional spatial structure within the pond. This structure provides natural shelter for the mud crabs, aligning with their habitat habits and helping to reduce aggression and cannibalism among individual crabs due to competition for space. Furthermore, the mangrove plants can absorb nutrients such as nitrogen and phosphorus from the water, thus purifying the water.

[0019] By setting up tidal channel network modules to connect aquaculture ponds with the open sea, the natural ebb and flow of tides and water exchange can be achieved through the tidal channel network. Seawater rich in dissolved oxygen and plankton from the open sea can be introduced into the aquaculture ponds, and metabolic waste in the aquaculture ponds can be discharged with the receding tide, thus achieving natural water renewal without relying on additional power equipment for forced water exchange.

[0020] By placing mud crab farming modules within the root distribution areas of the mangrove planting island modules, on both sides of the tidal channel network modules, and in the root areas of the mangrove belt modules, mud crabs can fully utilize the mangrove plant roots and seaweed farming modules as natural shelters. This helps reduce stress and cannibalism during the crab farming process. Furthermore, the crab excrement, once in the water, can be absorbed and utilized by the large seaweed in the mangrove and seaweed farming modules, resulting in in-situ transformation of aquaculture metabolic waste.

[0021] By setting up shellfish cultivation modules at the bottom of tidal channels, in areas where mangrove roots attach, and at the bottom of aquaculture ponds, filter-feeding shellfish can be cultivated. These shellfish can absorb organic debris, phytoplankton, and microorganisms from the water through filter feeding, effectively purifying the aquaculture water and reducing suspended solids and nutrient levels. Simultaneously, the larvae produced by the shellfish reproduction can serve as natural food for mud crabs, providing them with a continuous food source.

[0022] By setting up seaweed cultivation modules on the surface and in the lower layers of the aquaculture pond, large seaweeds are cultivated. These large seaweeds absorb solar energy and release oxygen through photosynthesis, effectively increasing the dissolved oxygen content in the aquaculture water. This meets the oxygen consumption needs of mangrove roots, crabs, and shellfish within the system, thereby reducing reliance on mechanical aeration equipment and lowering energy consumption. Simultaneously, the large seaweeds can assimilate and absorb nutrients such as nitrogen and phosphorus in the water, further purifying the water quality.

[0023] Overall, the ecological coupling aquaculture system of this invention constructs a complex ecosystem with close connections between four trophic levels: mangroves, mud crabs, shellfish, and large seaweed, through the coordinated operation of mangrove belt modules, mangrove planting island modules, tidal channel network modules, mud crab farming area modules, shellfish cultivation area modules, and seaweed farming area modules. This achieves functional complementarity and ecological niche misalignment among multiple trophic levels, enabling each component within the system to form a closed positive feedback loop, thus protecting the mangrove ecosystem while also ensuring the economic output of mud crab farming. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a first structural schematic diagram of an embodiment of the ecologically coupled aquaculture system provided by the present invention; Figure 2 This is a second structural schematic diagram of an embodiment of the ecologically coupled aquaculture system provided by the present invention; Figure 3 A schematic diagram of the first longitudinal section of the embankment-mangrove belt module-tidal channel network module-mangrove planting island module of an embodiment of the ecological coupling aquaculture system provided by the present invention; Figure 4 A schematic diagram of the second longitudinal section of the embankment-mangrove belt module-tidal channel network module-mangrove planting island module of an embodiment of the ecological coupling aquaculture system provided by the present invention; Figure 5 A schematic diagram of the third longitudinal section of an embodiment of the ecologically coupled aquaculture system provided by the present invention, consisting of a dam-mangrove belt module-tidal channel network module-mangrove planting island module. Figure 6 A first schematic diagram of the root system soil stabilization and embankment protection mechanism of a mangrove belt module in an embodiment of the ecologically coupled aquaculture system provided by the present invention; Figure 7 A second schematic diagram of the root system soil stabilization and embankment protection mechanism of a mangrove belt module in an embodiment of the ecologically coupled aquaculture system provided by the present invention; Figure 8 A third schematic diagram of the root system soil stabilization and embankment protection mechanism of a mangrove belt module in an embodiment of the ecological coupling aquaculture system provided by the present invention; Figure 9 This is a flowchart illustrating the first embodiment of the ecological coupling aquaculture method provided by the present invention. Figure 10This is a flowchart illustrating the second embodiment of the ecological coupling aquaculture method provided by the present invention; Figure 11 This is a first schematic diagram illustrating the synergistic relationship of the three-chain integration in any embodiment of the ecological coupling aquaculture method provided by the present invention; Figure 12 This is a second schematic diagram illustrating the synergistic relationship of the three-chain integration in any embodiment of the ecological coupling aquaculture method provided by the present invention; Figure 13 This is a third schematic diagram illustrating the synergistic relationship of the three-chain integration in any embodiment of the ecological coupling aquaculture method provided by the present invention.

[0026] Explanation of icon numbers: 1. Mangrove belt module; 2. Mangrove planting island module; 3. Crab farming area module; 4. Shellfish cultivation area module; 5. Seaweed farming area module; 6. Farming pond.

[0027] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0030] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0031] Mangroves are woody plant communities that grow in the intertidal zone of tropical and subtropical coasts and are periodically submerged by seawater. They play important ecological functions such as wind and wave protection, shoreline stabilization, carbon sequestration, and maintaining biodiversity. However, large-scale aquaculture and land reclamation in the past have severely squeezed the living space of mangroves, leading to ecological degradation. How to protect the mangrove ecosystem while ensuring the economic benefits of aquaculture has become an urgent technical challenge.

[0032] Currently, some technical solutions involving the coupling of mangroves and aquaculture have been proposed. For example, by configuring mangrove plants and aquatic animals in aquaculture ponds and regulating water levels, both mangrove protection and aquaculture can be achieved; or by constructing planting islands in the middle of aquaculture ponds to plant mangrove plants, and combining them with aquatic plants and large algae for mud crab farming.

[0033] However, the current aquaculture schemes mentioned above still have shortcomings. First, the system components are limited in level, mostly remaining at the binary or ternary combination level, failing to systematically integrate the functions of multiple trophic levels. Second, there is a lack of proactive design for material cycling and energy utilization within the system, and the components have not formed a closed positive feedback loop. Third, the spatial layout is relatively extensive, with strong reliance on mechanical aeration and high operation and maintenance costs. Fourth, the survival rate of mud crab farming still needs to be further improved.

[0034] To address one or more technical problems in the aforementioned aquaculture schemes, this invention proposes an ecologically coupled aquaculture system.

[0035] Please see Figures 1 to 5 In one embodiment of the present invention, the ecologically coupled aquaculture system is deployed in the intertidal zone with tidal exchange conditions, and the ecologically coupled aquaculture system includes: Mangrove belt module 1 is planted on the bank of the embankment of aquaculture pond 6 to form a continuous mangrove belt, which is used to stabilize the soil and protect the embankment to form an ecological barrier, and to provide a source of litter for aquaculture pond 6; Mangrove planting island module 2 is located in the internal area of ​​aquaculture pond 6, and mangrove plants are planted on mangrove planting island module 2; The tidal channel network module connects the aquaculture pond 6 with the open sea, and is used to regulate water quality through tidal exchange. The mud crab farming area module 3 is located in at least one of the root distribution area of ​​the mangrove planting island module 2, both sides of the tidal channel network module, and the root area of ​​the mangrove belt module 1, and is used for releasing mud crabs. Module 4, a shellfish cultivation area, is located at least once in one of the following locations: the bottom of the tidal channel network, the root attachment area of ​​mangrove plants, and the bottom area of ​​the cultivation pond 6, for cultivating filter-feeding shellfish; and Module 5, the seaweed cultivation area, is located on the surface and in the lower layers of the water in the cultivation pond 6 and is used for cultivating large seaweed.

[0036] The technical solution of this invention involves planting mangrove belt modules 1 along the banks of the embankment of the aquaculture pond 6, forming a continuous mangrove belt. Due to the extensive root network of mangrove plants, this network can stabilize the soil and protect the embankment, thus creating an ecological barrier along the embankment bank. This effectively reduces the risk of embankment erosion by sea waves and decreases the periodic reinforcement and maintenance costs of the embankment. Simultaneously, the litter from the mangrove belt modules 1 enters the aquaculture water through tidal action and natural fall, becoming an important source of organic debris within the aquaculture system after decomposition by microorganisms. This provides a natural food basis for subsequent shellfish cultivation, achieving a synergy between the ecological barrier function and the food production function.

[0037] By setting up mangrove planting island modules 2 within the internal area of ​​the aquaculture pond 6, and planting mangrove plants on these modules, the root systems of the mangroves create a staggered, three-dimensional spatial structure within the pond 6. This structure provides a natural shelter for the mud crabs, aligning with their habitat habits and helping to reduce attacks and cannibalistic behaviors among individual crabs due to competition for space. Furthermore, the mangroves can absorb nutrients such as nitrogen and phosphorus from the water, thus purifying the water.

[0038] By setting up a tidal channel network module to connect the aquaculture pond 6 with the open sea, the natural ebb and flow of tides and water exchange can be achieved through the tidal channel network. Seawater rich in dissolved oxygen and plankton from the open sea can be introduced into the aquaculture pond 6, and metabolic waste in the aquaculture pond 6 can be discharged with the receding tide, thus achieving natural water renewal without relying on additional power equipment for forced water exchange.

[0039] By setting up the mud crab farming area module 3 in the root distribution area of ​​the mangrove planting island module 2, on both sides of the tidal channel network module, and in the root area of ​​the mangrove belt module 1, mud crabs are released into these areas. This allows the mud crabs to fully utilize the mangrove plant roots and the seaweed farming area module 5 as natural shelters, which helps reduce stress and cannibalism during the mud crab farming process. In addition, the excrement of mud crabs can be absorbed and utilized by the large seaweed in the mangrove plant and seaweed farming area module 5 after entering the water body, forming an in-situ transformation of farming metabolic waste.

[0040] By setting up shellfish cultivation module 4 at the bottom of the tidal channel network, the root attachment area of ​​mangrove plants, and the bottom area of ​​the aquaculture pond 6, filter-feeding shellfish are cultivated. These shellfish can absorb organic debris, phytoplankton, and microorganisms from the water through filter feeding, effectively purifying the aquaculture water and reducing suspended solids and nutrient content. Simultaneously, the larvae produced by shellfish reproduction can serve as natural food for mud crabs, providing a continuous food source.

[0041] By setting up seaweed cultivation module 5 on the surface and lower layers of the water in the cultivation pond 6, large seaweed can be cultivated. The large seaweed absorbs solar energy and releases oxygen through photosynthesis, effectively increasing the dissolved oxygen content in the cultivation water. This meets the oxygen consumption needs of mangrove roots, crabs, and shellfish within the system, thereby reducing reliance on mechanical aeration equipment and lowering energy consumption. Simultaneously, the large seaweed can assimilate and absorb nutrients such as nitrogen and phosphorus in the water, further purifying the water quality.

[0042] Overall, the ecologically coupled aquaculture system of the present invention constructs a complex ecosystem with close connections between four trophic levels: mangroves, mud crabs, shellfish, and large seaweed, through the coordinated operation of mangrove belt module 1, mangrove planting island module 2, tidal channel network module, mud crab farming area module 3, shellfish cultivation area module 4, and seaweed farming area module 5. This achieves functional complementarity and ecological niche misalignment among multiple trophic levels, enabling each component in the system to form a closed positive feedback loop, thus protecting the mangrove ecosystem while taking into account the economic output of mud crab farming.

[0043] It should be noted that the intertidal zone refers to the coastal zone between the mean high tide line and the mean low tide line, which is subject to periodic tidal inundation. An intertidal zone with tidal exchange conditions refers to an intertidal zone where natural water exchange with the open sea is achieved through tidal fluctuations. Mangrove belt module 1 refers to the continuous strip-shaped plant community formed by mangrove plants along the banks of the aquaculture pond 6 dike. This plant community can enhance the structural stability of the dike through the soil-fixing effect of the plant roots (see reference...). Figures 6 to 8Aquaculture pond 6 refers to a pond structure for aquaculture that is modified or newly built based on traditional aquaculture ponds 6 in coastal wetlands, and it has dikes and a pond bottom. Litter refers to the naturally shed branches, leaves, flowers, fruits, and other plant remains of mangrove plants. After entering the water, these remains are decomposed and leached by microorganisms, forming organic debris and soluble substances, providing a food source for shellfish and other organisms in the aquaculture system. Filter-feeding shellfish are shellfish that feed by filtering suspended particulate matter (including phytoplankton, zooplankton, organic debris, etc.) from the water, such as mussels, oysters, and razor clams.

[0044] In the specific operation, aquaculture pond 6 is first constructed in a selected intertidal zone with tidal exchange conditions. Mangrove plants are planted along the banks of the surrounding dikes of aquaculture pond 6, forming a mangrove belt of suitable width. After planting, the mangrove plants gradually develop a well-developed root network during their growth. This root network penetrates deep into the dike soil, enhancing the structural stability of the dike through the anchoring effect of the roots and reducing the erosion caused by waves. Simultaneously, the mangrove plants continuously produce litter during their growth, which falls into the water of aquaculture pond 6 under the influence of gravity and tidal currents. Mangrove planting islands are then constructed within the interior of aquaculture pond 6, and mangrove plants are planted on these islands, creating artificial mangrove patches within the pond. The mangrove root systems on the planting islands form a three-dimensional spatial structure within aquaculture pond 6, providing habitat and shelter for the subsequently released mud crabs. A network of tidal channels connecting aquaculture pond 6 to the open sea is constructed. Gates are installed within this network to control water exchange between pond 6 and the open sea. During high tide, the gates are opened to allow seawater from the open sea to flow into pond 6 through the tidal channels, replenishing its water volume and dissolved oxygen, and introducing larval plankton from the open sea. During low tide, the gates are opened to allow water from pond 6 to flow out through the tidal channels, discharging metabolic waste generated during the aquaculture process. At least one location—the root distribution area of ​​mangrove planting island module 2, both sides of the tidal channel network module, and the root area of ​​mangrove belt module 1—is designated as a mud crab aquaculture zone module 3 for subsequent mud crab stocking. At least one location—the bottom of the tidal channel network, the root attachment area of ​​mangrove plants, and the bottom area of ​​pond 6—is designated as a shellfish cultivation zone module 4, where filter-feeding shellfish seedlings are stocked. Seaweed cultivation zone modules 5 are established on the water surface and in the lower layers of pond 6 for the cultivation of large seaweeds. After a period of ecological establishment, once mangrove plants, shellfish, and large seaweed have been initially established within the aquaculture system, mud crab seedlings are introduced into module 3 of the mud crab farming area. During the farming process, the excrement and uneaten feed of the mud crabs enter the water, where nutrients such as nitrogen and phosphorus are absorbed and utilized by the mangrove plants and large seaweed. Mangrove litter is decomposed by microorganisms to form organic debris, which is then filtered by filter-feeding shellfish in module 4 of the shellfish farming area. The planktonic larvae produced by the reproduction of filter-feeding shellfish enter the water and become natural food for the mud crabs. Large seaweed releases oxygen through photosynthesis, increasing the dissolved oxygen content of the water, while simultaneously assimilating and absorbing nitrogen and phosphorus nutrients from the water. The water in farming pond 6 undergoes periodic tidal exchange with the open sea through the tidal channel network module, achieving natural water renewal.

[0045] As one feasible implementation method, the aquaculture pond 6 can be formed by welding polypropylene sheets or by casting reinforced concrete. The length and width of the aquaculture pond 6 can be adjusted according to the actual site conditions.

[0046] Furthermore, as a feasible implementation method, the mangrove plants in mangrove belt module 1 can be selected from one or more of the following: *Symplocos lucida*, *Kandelia candel*, *Avicennia marina*, *Rhizophora stylosa*, and *Rhizophora mukorossi*. Preferably, a mixture of multiple mangrove plants is used to improve the biodiversity and ecological stability of the mangrove belt. Similarly, the mangrove plants on mangrove planting island module 2 can also be selected from one or more of the aforementioned mangrove plants.

[0047] In addition, as a feasible implementation method, the filter-feeding shellfish cultivated in the shellfish cultivation module 4 can be selected from at least one of mussels, oysters, and razor clams. The large seaweed in the seaweed cultivation module 5 can be selected from at least one of Gracilaria, Asparagus setaceus, and kelp.

[0048] In an embodiment of the present invention, the seaweed aquaculture zone module 5 includes a floating seaweed layer on the water surface and a suspended seaweed layer underwater. The coverage rate of the floating seaweed layer on the water surface is 20%-40% of the water area of ​​the aquaculture pond 6, and the coverage rate of the suspended seaweed layer underwater is 15%-30% of the water volume. And / or, the floating seaweed layer on the water surface is used for shading and primary dissolved oxygen supply during the day, and the suspended seaweed layer underwater is used for water oxygenation and nitrogen and phosphorus absorption, and forms a dissolved oxygen distribution in the vertical direction of the aquaculture water.

[0049] In this embodiment, by setting the seaweed cultivation area module 5 as a two-layer three-dimensional structure with a floating seaweed layer on the water surface and a suspended seaweed layer underwater, the surface space and vertical water space of the cultivation pond 6 are fully utilized, increasing the cultivation area and capacity of large seaweed, thereby improving the photosynthetic efficiency per unit water area. The floating seaweed layer is set on the surface of the water in the cultivation pond 6, with a coverage rate of 20% to 40% of the water area. This coverage rate ensures sufficient photosynthetic oxygen production without affecting gas exchange and light penetration at the water surface due to excessive coverage. During the day, the floating seaweed layer releases oxygen through photosynthesis, providing primary dissolved oxygen supply to the cultivation water. At the same time, the seaweed layer forms a shading effect on the water surface, effectively reducing heat absorption by the water surface of the cultivation pond 6 under strong sunlight in summer, reducing the diurnal fluctuation range of water temperature, and thus reducing the heat stress response of mud crabs caused by drastic water temperature changes. The underwater suspended seaweed layer is located in the lower layer of the water in aquaculture pond 6, covering 15% to 30% of the water volume. This seaweed layer forms a multi-layered dissolved oxygen replenishment in the vertical direction of the aquaculture water, preventing hypoxia in the bottom water due to its distance from the surface and lack of photosynthesis. This results in a more uniform distribution of dissolved oxygen in the vertical direction of the aquaculture water, effectively preventing damage to shellfish and mud crabs caused by hypoxia in the bottom water. At the same time, the underwater suspended seaweed layer can continuously assimilate and absorb nitrogen and phosphorus nutrients in the water, playing a role in deep purification of the aquaculture water. Overall, this embodiment achieves three-dimensional oxygenation and vertical dissolved oxygen balance in the aquaculture water through the dual-layer vertical layout of the floating seaweed layer and the underwater suspended seaweed layer, effectively reducing the frequency and operating time of mechanical aeration equipment and lowering aquaculture energy consumption.

[0050] It should be noted that the floating seaweed layer refers to the layered structure on the surface of the aquaculture pond (6) where large seaweed is cultivated using floating carriers such as rafts or floating nets. In this layer, the large seaweed floats near the surface, allowing it to fully receive sunlight for photosynthesis. The suspended seaweed layer refers to the layered structure from the middle to the bottom of the aquaculture pond (6) where large seaweed is cultivated using suspended carriers such as rope frames or net cages. In this layer, the large seaweed is suspended in the lower layers of the water, performing photosynthesis and absorbing nutrients from the water under low-light conditions.

[0051] In the specific operation, floating rafts or floating net frames are set up on the surface area of ​​aquaculture pond 6 to fix large seaweed seedlings, forming a floating seaweed layer on the water surface. Below this floating seaweed layer, from the middle to the bottom of the water, hanging rope frames or net cages are set up to fix large seaweed seedlings, forming an underwater suspended seaweed layer. The coverage rate of the floating seaweed layer is controlled between 20% and 40% of the water area of ​​aquaculture pond 6. During the day, the large seaweed in the floating seaweed layer undergoes photosynthesis under sunlight, converting absorbed carbon dioxide and water into organic matter, while releasing oxygen into the water, providing dissolved oxygen replenishment to the surface water of aquaculture pond 6. Because the floating seaweed layer covers the water surface, it blocks some direct sunlight from reaching the water, reducing heat absorption from the water surface and lowering the temperature rise of aquaculture pond 6 in summer. Large algae in the underwater suspended algae layer carry out photosynthesis in the lower and middle layers of the water in aquaculture pond 6. Because the underwater light intensity is lower than that at the water surface, the photosynthetic rate of the algae layer in the underwater suspended algae layer is relatively slow. However, it can continuously assimilate and absorb nitrogen and phosphorus nutrients in the water during the day and night, and continuously replenish dissolved oxygen in the middle and bottom layers of the water, thereby effectively avoiding the hypoxia phenomenon in the bottom layer caused by water stratification.

[0052] As a feasible implementation method, the seaweed layer in the floating area and the seaweed layer in the underwater hanging area can cultivate the same type of large seaweed, or different types of large seaweed. For example, Gracilaria can be cultivated in the floating seaweed layer, and Gracilaria can be cultivated in the underwater hanging seaweed layer.

[0053] Furthermore, as a feasible implementation method, the coverage rate of the seaweed layer in the floating area can be adjusted according to the light intensity and temperature conditions of different seasons. In summer when the sunlight is strong, the coverage rate of the seaweed layer in the floating area can be adjusted to close to 40% to enhance the shading and cooling effect; in winter when the sunlight is insufficient, the coverage rate of the seaweed layer in the floating area can be adjusted to close to 20% to ensure that the water body can receive sufficient sunlight.

[0054] In an embodiment of the present invention, the filter-feeding shellfish cultivated in the shellfish cultivation area module 4 produce larvae that serve as natural food for the mud crabs in the mud crab farming area module 3; the organic debris formed by the decomposition of litter from the mangrove forest module 1 by microorganisms serves as food for the filter-feeding shellfish.

[0055] In this embodiment, the mangrove plants in the mangrove belt module 1 continuously produce litter during their growth. This litter enters the water body of the aquaculture pond 6 and is gradually decomposed by microorganisms, forming organic debris rich in organic matter and nutrients. This organic debris either floats in the water or settles at the bottom of the pond, becoming a natural food source for filter-feeding shellfish in the shellfish cultivation area module 4. Filter-feeding shellfish ingest this organic debris through filter feeding, obtaining the nutrients needed for growth and effectively removing suspended organic matter from the water, thus purifying the water quality. Simultaneously, under suitable environmental conditions, the filter-feeding shellfish reproduce, producing a large number of planktonic larvae. These planktonic larvae are carried by the water flow to the mud crab farming area module 3, where they are preyed upon by the mud crabs, becoming high-quality natural food. Compared to artificially fed formulated feed, shellfish larvae, as natural live food, better suit the feeding habits of mud crabs, meeting their nutritional needs at different growth stages, while reducing the amount and frequency of artificial feed, thus lowering aquaculture costs. Overall, this embodiment decomposes the litter in mangrove module 1 to provide food for filter-feeding shellfish, and then provides natural food for mud crabs through the larvae produced by the reproduction of filter-feeding shellfish. This forms a cascade food transfer path of mangrove litter - shellfish food - shellfish larvae - mud crab feeding, realizing multi-level utilization and transformation of nutrients within the system.

[0056] It should be noted that organic debris formed from the decomposition of litter by microorganisms refers to the fine organic particles formed from the leaching, decomposition, and fragmentation of mangrove plant remains such as fallen leaves and branches under the influence of water immersion and microbial activity. These particles are suspended in the water or deposited on the bottom and can be ingested by filter-feeding shellfish. The larvae produced by filter-feeding shellfish refer to the planktonic larvae that develop after hatching from fertilized eggs released by shellfish during the breeding season. These larvae are tiny, suspended in the water column, and serve as high-quality natural food for carnivorous crustaceans such as mud crabs.

[0057] In the specific operation process, during the growth of mangrove plants in module 1, the aging leaves, dead branches, and mature flowers and fruits naturally fall under gravity or are detached from the parent plant by wind, waves, and tidal currents, falling into the water body of aquaculture pond 6. The fallen debris entering the water body is gradually decomposed into fine organic debris particles by bacteria, fungi, and other microorganisms in the water. These organic debris particles are suspended in the water and diffuse with the water flow to module 4, the shellfish cultivation area. Filter-feeding shellfish in module 4, such as mussels, oysters, and razor clams, continuously draw water through their well-developed filter organs, trapping and consuming the organic debris particles as a source of nutrition for their growth and reproduction. After consuming the organic debris, the filter-feeding shellfish obtain sufficient nutrition and reproduce under suitable water temperature conditions, producing a large number of fertilized eggs. After the fertilized eggs develop into planktonic larvae, these larvae are carried by the water flow into module 3, the mud crab cultivation area. The mud crabs in Module 3 of the mud crab farming area are carnivorous crustaceans that actively prey on planktonic larvae of shellfish in the water, using them as their primary natural food source. During this feeding process, the mud crabs obtain ample protein, amino acids, and other nutrients, promoting their growth and development.

[0058] In an embodiment of the present invention, in the spatial layout of the ecologically coupled aquaculture system, the mangrove belt module 1 occupies 10%-20% of the total system area, the mangrove planting island module 2 occupies 5%-15% of the total system area, the tidal channel network module occupies 10%-20% of the total system area, the mud crab farming area module 3 occupies 20%-40% of the total system area, and the shellfish cultivation area module 4 occupies 15%-20% of the total system area.

[0059] In this embodiment, by spatially arranging the various functional modules of the ecologically coupled aquaculture system according to the aforementioned proportions, a reasonable spatial ratio is achieved between the modules within the system. The mangrove belt module 1 occupies 10% to 20% of the total system area, ensuring sufficient width and area of ​​the mangrove belt along the shore to form an effective ecological barrier, while also generating sufficient litter for shellfish to feed on. The mangrove planting island module 2 occupies 5% to 15% of the total system area, providing ample mangrove patches within the aquaculture pond 6 to offer shelter and habitat for the mud crabs, while ensuring a sufficiently large root system for effective absorption of nutrients from the water. The tidal channel network module occupies 10% to 20% of the total system area, ensuring sufficient cross-sectional area for the tidal channels, facilitating smooth tidal exchange between the aquaculture pond 6 and the open sea, and achieving effective water renewal. The mud crab aquaculture area module 3 occupies 20% to 40% of the total system area, providing ample space for the mud crabs and preventing overcrowding that could lead to intensified competition among individuals. Module 4, the shellfish rearing area, occupies 15% to 20% of the total system area, ensuring sufficient rearing space for shellfish to produce a considerable number of larvae, providing ample natural food for the mud crabs. Through the synergistic coordination of the above proportions, the functions of each module are fully utilized, and the overall material cycling efficiency and energy utilization efficiency of the system are optimized.

[0060] It should be noted that the total system area refers to the sum of the water surface area of ​​aquaculture pond 6 and the area of ​​the mangrove belt along the embankment, that is, the total space occupied by the entire ecologically coupled aquaculture system. The area ratio of each module refers to the ratio of the projected area or land area of ​​that module in aquaculture pond 6 to the total system area.

[0061] In an embodiment of the present invention, the planting density of mangrove plants on the mangrove planting island module 2 is 1-5 plants per square meter; the tidal channel network module includes a main tidal channel and branch tidal channels, the width of the tidal channels is 1-5m and the depth is 0.5-2m, and the tidal channel network module is equipped with gates to control the exchange of water with the open sea.

[0062] In this embodiment, the planting density of mangrove plants on the mangrove planting island module 2 is 1 to 5 plants per square meter. This planting density ensures sufficient growth space for individual mangrove plants to avoid excessive competition, while also allowing the mangroves to form a relatively closed canopy layer on the planting island, providing ample shade and shelter for the mud crabs. The tidal channel network module includes main tidal channels and branch tidal channels. The main tidal channels play a major role in water transport, while the branch tidal channels divert water and expand the tidal exchange range. The width of the tidal channels is 1 to 5 meters, and the depth is 0.5 to 2 meters. This size ensures that the tidal channels have sufficient water carrying capacity to complete the tidal water exchange with the open sea, while avoiding excessive width and depth that would occupy too much aquaculture water surface area. The tidal channel network module is equipped with gates. By opening and closing the gates, operators can flexibly control the time and amount of water exchange between the aquaculture pond 6 and the open sea according to tidal patterns and aquaculture needs, realizing active regulation of the water level in the aquaculture pond 6.

[0063] It should be noted that the main tidal channel refers to the primary channel in the tidal channel network, with a larger cross-sectional size, and performs the main functions of water intake and drainage. Branch tidal channels refer to secondary channels connected to the main tidal channel, with smaller cross-sectional sizes, used to introduce water into various areas of the aquaculture pond 6. A sluice gate is a hydraulic structure that can be opened and closed, located at the junction of the tidal channel and the open sea; the opening and closing of the sluice gate controls the flow and interception of water.

[0064] In the specific operation, during the planning and layout stage of aquaculture pond 6, the direction and layout of the tidal channel network are determined according to the shape and area of ​​aquaculture pond 6. The main tidal channel is set along the length of aquaculture pond 6, extending from the water inlet side to the water outlet side. Branch tidal channels extend from the main tidal channel to both sides, reaching into various areas inside aquaculture pond 6. Gates are installed at the junction of the tidal channels and the outer side of aquaculture pond 6. When water needs to be introduced, the gates are opened during high tide according to tidal forecasts, allowing seawater from the open sea to flow into aquaculture pond 6 through the main tidal channel driven by the tidal difference, and then dispersed to various areas of aquaculture pond 6 through the branch tidal channels. When water needs to be discharged, the gates are opened during low tide, allowing water in aquaculture pond 6 to flow into the main tidal channel through the branch tidal channels under gravity, and then discharged into the open sea through the main tidal channel.

[0065] Furthermore, as a feasible implementation method, the gate can be a manually operated gate or an electrically or hydraulically driven automatic gate. Preferably, an automatic gate is used in conjunction with an automatic tidal control system to achieve automatic opening and closing of the gate according to a preset tidal schedule.

[0066] Please see Figure 9 The present invention also proposes an ecological coupling aquaculture method, which uses the above-mentioned ecological coupling aquaculture system for ecological coupling aquaculture, the method comprising steps S10 to S60: Step S10: Construct or modify aquaculture ponds in the selected intertidal zone and divide them into modular functional zones to form mangrove belt modules, mangrove planting island modules, tidal channel network modules, mud crab aquaculture area modules, shellfish cultivation area modules, and seaweed aquaculture area modules. Step S20: Plant mangrove plants in the mangrove belt module and the mangrove planting island module to form an ecological barrier; Step S30: Shellfish seedlings are introduced into the shellfish cultivation area module, and large seaweeds are introduced into the seaweed cultivation area module; Step S40: Crab seedlings are released into the crab farming area module, and the crabs feed on the shellfish as natural food. Step S50: During the breeding period, the system operates to form a coordinated closed loop of material cycle chain, energy utilization chain and economic value chain, and regulates the breeding environment parameters. In step S60, after the aquaculture is completed, the mud crabs are harvested, the large seaweed and shellfish are collected, and the carbon sequestration of the mangrove plants is calculated and evaluated.

[0067] In this embodiment, aquaculture ponds are first constructed or modified within a selected intertidal zone and then modularly divided into six functional modules, thus establishing a physical platform and spatial foundation for subsequent ecologically coupled aquaculture. By planting mangrove plants in the mangrove belt and mangrove planting island modules, these plants establish themselves along the banks and within the aquaculture ponds, gradually forming ecological barriers and sheltered habitats, providing habitats for the subsequently released mud crabs. Simultaneously, the mangrove plants begin to absorb nutrients from the water and produce litter, activating the system's ecological functions. By introducing shellfish seedlings into the shellfish cultivation module and large seaweed into the seaweed cultivation module, filter-feeding shellfish and photosynthetically oxygen-producing large seaweed are introduced into the system, establishing a biological basis for water purification and natural food production. Finally, by introducing mud crab seedlings into the mud crab cultivation module, the mud crabs become the top-level consumers in the system, feeding on the larvae produced by shellfish reproduction as natural food. By establishing a synergistic closed-loop system encompassing material circulation, energy utilization, and economic value chains during the aquaculture period, and by regulating environmental parameters, the system ensures the continuous flow of matter, energy, and value among its various biological components along designed pathways. Crab excrement is absorbed and utilized by mangrove plants and algae; mangrove litter is decomposed by microorganisms to become food for shellfish; shellfish larvae are consumed by the crabs; and large algae provide oxygen through photosynthesis, supplying oxygen to the system's respiration, thus forming a complete positive feedback loop. Simultaneously, the regulation of environmental parameters ensures suitable growth conditions for each biological component. Harvesting the crabs after aquaculture generates the primary economic output, while harvesting the large algae and shellfish generates secondary economic output. Furthermore, the carbon sequestration capacity of the mangrove plants is assessed to quantify the value of the carbon sink.

[0068] Overall, this method integrates system construction, biological release, ecological operation, and harvest accounting in a reasonable time sequence, realizing a complete process from physical platform construction to the realization of ecological functions and economic value.

[0069] It should be noted that modular functional zoning refers to dividing the aquaculture pond into independent modules with different ecological functions based on the functional positioning of different areas of the aquaculture system. These modules are spatially adjacent and functionally complementary, together forming a complete ecosystem. The ecological construction period refers to the time required from the completion of mangrove planting, shellfish and seaweed introduction, to the initial establishment of ecological connections among various biological components within the system, and the system's tendency to stabilize.

[0070] In the specific operation process, the first step is to assess the abandoned or inefficient aquaculture ponds in the selected intertidal zone to determine the pond's dike structure, bottom elevation, and tidal conditions. Based on the assessment results, the aquaculture ponds are renovated or newly constructed. Planting areas for mangrove belt modules are reserved along the dike banks around the ponds. The locations of mangrove planting island modules are demarcated within the ponds, and planting islands are constructed. A tidal channel network module connecting to the open sea is built, and gates are installed. The locations and extents of the mud crab farming area, shellfish cultivation area, and seaweed farming area modules are demarcated. After completing the modular functional zoning, mangrove seedlings are planted in the mangrove belt modules and mangrove planting island modules according to the designed planting density and row spacing. The survival rate of the mangrove plants is monitored regularly after planting, and replanting is carried out when the survival rate is insufficient. After the mangrove planting is completed, filter-feeding shellfish seedlings are introduced into the shellfish cultivation area module, and large seaweed seedlings are introduced into the floating area on the water surface and the suspended area underwater in the seaweed farming area module. After a period of ecological establishment, once mangrove plants, shellfish, and large seaweed have initially established themselves and stabilized within the system, mud crab seedlings are released into the mud crab farming module. During the farming period, water exchange between the farming ponds and the open sea is controlled through sluice gates according to tidal patterns. Environmental parameters such as water temperature, salinity, and dissolved oxygen content in the farming ponds are monitored and controlled to ensure the continuous operation of the material cycle, energy utilization chain, and economic value chain within the system. After the farming cycle ends, the mud crabs are harvested, and large seaweed and shellfish are selectively harvested. The carbon sequestration capacity of mangrove plants in the mangrove belt module and mangrove planting island module is calculated and evaluated.

[0071] As a feasible implementation method, in step S10, the transformation of the aquaculture pond can be carried out on the basis of the original abandoned or inefficient aquaculture pond. The system transformation can be completed by reinforcing the dikes, dredging the tidal channels, building planting islands and setting up seaweed aquaculture facilities. There is no need to excavate the pond again, which reduces the engineering cost and construction difficulty.

[0072] In addition, as a feasible implementation method, in step S40, the mud crab seedlings are released 3 to 6 months after the completion of the ecological construction period following the planting of mangrove plants and the release of shellfish and seaweed, to ensure that sufficient natural food base and shelter environment have been formed in the system before releasing the mud crab seedlings, so as to improve the survival rate of mud crabs.

[0073] In an embodiment of the present invention, please refer to Figure 10 In step S50, the step of regulating the aquaculture environment parameters includes steps S51-S52: Step S51: Control the dissolved oxygen content of the aquaculture pond water to be no less than 4.0 mg / L, the salinity to be controlled at 15-30 ppt, and the water temperature to be controlled at 20-33℃; Step S52: Control the pond water level within 10-30cm above the average elevation of the mangrove planting island module, and intermittently expose the aerial roots and breathing roots of the mangrove plants to the water surface.

[0074] In this embodiment, step S51 controls the dissolved oxygen content of the aquaculture pond water to above 4.0 mg / L, ensuring the normal respiration oxygen consumption of the mud crabs, shellfish, and mangrove roots, preventing aquatic animals from surfacing or dying due to oxygen deficiency, and providing an aerobic environment for microorganisms to decompose litter. Salinity is controlled between 15 and 30 ppt, and water temperature between 20 and 33°C; these parameters are suitable for the normal growth and reproduction of mud crabs, filter-feeding shellfish, and mangrove plants. Step S52 controls the pond water level to be within 10 to 30 cm above the average elevation of the mangrove planting island modules, ensuring that the mangrove roots on the planting island modules are always submerged. This guarantees that the mangroves can absorb nutrients through the water, while preventing the water level from becoming too high and submerging the mangrove canopy, thus avoiding excessive inhibition of mangrove photosynthesis. By intermittently exposing the aerial roots and respiratory roots of mangrove plants to the water surface, this method ensures that the mangrove root system receives intermittent exposure to water and aeration, preventing degeneration or death caused by root hypoxia due to prolonged and continuous flooding. Overall, this embodiment, through precise control of dissolved oxygen, salinity, water temperature, and water level, provides suitable growth conditions for all biological components within the system, ensuring the stable operation of the ecologically coupled aquaculture system.

[0075] It should be noted that aerial roots refer to adventitious roots that grow from the stems or branches of mangrove plants and are exposed to the air. These roots have respiratory functions and can absorb oxygen from the air when the tide recedes. Breathing roots refer to special root systems of mangrove plants that grow upwards from underground roots and extend above the water or soil surface. Their surfaces have lenticel structures, which allow for gas exchange when the tide recedes.

[0076] During the specific operation, operators monitor the dissolved oxygen content in the aquaculture ponds in real time using dissolved oxygen monitoring equipment. When the dissolved oxygen content is below 4.0 mg / L, the dissolved oxygen content is increased by increasing the cultivation area of ​​large seaweed, increasing the tidal water exchange, or turning on auxiliary aeration equipment. Water salinity and temperature are monitored using salinity meters and thermometers. When salinity deviates from the range of 15 to 30 ppt, it is adjusted by regulating the water exchange with the open sea or by supplementing with freshwater. When water temperature deviates from the range of 20 to 33℃, the coverage of the seaweed layer in the floating area is increased during the high temperatures of summer to enhance the shading and cooling effect, and the water level is deepened during the low temperatures of winter to utilize the water's heat capacity for insulation. The water intake and drainage of the aquaculture pond are controlled by sluice gates. The gates are opened and closed in a timely manner according to the tidal pattern and the pond water level monitoring results, so that the pond water level is maintained within 10 to 30 centimeters above the average elevation of the mangrove planting island module, and the aerial roots and breathing roots of mangrove plants are intermittently exposed to the water surface during low tide.

[0077] Please see Figures 11 to 13 In an embodiment of the present invention, the material cycle is as follows: the nutrients in the excrement and uneaten food of the mud crabs are absorbed and utilized by mangrove plants; the dead branches and fallen leaves of the mangrove plants fall into the water and are decomposed by microorganisms into natural food for shellfish, which are then consumed by the mud crabs.

[0078] In this embodiment, through the operation of the aforementioned material cycle, the excrement and uneaten feed produced by the mud crabs during the aquaculture process enter the water body. The nitrogen, phosphorus, and other nutrients in these substances dissolve in the water and are absorbed by the mangrove plants in the mangrove belt module and mangrove planting island module through their roots, serving as a fertilizer source for mangrove plant growth. The mangrove plants utilize these nutrients for growth and metabolism, and the resulting fallen leaves and other debris fall into the aquaculture pond. Microorganisms in the water decompose the debris, transforming it into organic detritus rich in organic matter and nutrients. This organic detritus becomes natural food for filter-feeding shellfish in the shellfish rearing area module. After consuming the organic detritus, the filter-feeding shellfish grow and reproduce, and their planktonic larvae are carried by the water flow into the mud crab aquaculture area module, where they are preyed upon by the mud crabs. Thus, the nutrients in the mud crab excrement return to the mud crab's food chain through the pathway of mangrove plant absorption – debris decomposition – shellfish filter feeding – shellfish larvae – mud crab feeding, forming a closed material cycle loop. This material recycling chain enables the in-situ transformation and efficient utilization of aquaculture metabolic waste within the system, reducing the need for exogenous feed and lowering the nutrient content in aquaculture wastewater, thus alleviating pollution pressure on the offshore environment.

[0079] It should be noted that nutrients refer to mineral elements dissolved in water that can be absorbed and utilized by plants. These mainly include elements such as nitrogen and phosphorus and their compounds, and are essential sources of nutrients for plant growth.

[0080] In the specific operation, the mud crabs in the mud crab farming module produce excrement during feeding and metabolism. Simultaneously, some of the artificial feed is not consumed by the mud crabs, forming uneaten feed. The organic matter in this excrement and uneaten feed is converted into dissolved nutrients such as ammonium salts, nitrates, and phosphates through ammoniation and nitrification processes by microorganisms in the water. These dissolved nutrients diffuse with the water flow to the root zones of mangrove plants in the mangrove belt and mangrove planting island modules. The mangrove roots absorb these nutrients from the water through active and passive absorption for their own growth and development. During the growth process, mangrove plants shed their aged leaves, dead branches, and fruits into the water. Aerobic and facultative microorganisms in the water attach to the surface of the litter, secreting extracellular enzymes to decompose large organic molecules such as cellulose and lignin, converting them into smaller organic debris and soluble organic matter. These organic debris are transported with the water flow to the shellfish cultivation module. In the shellfish rearing module, filter-feeding shellfish ingest organic detritus through water filtration, assimilating it into their own tissue components. After consuming the organic detritus, the filter-feeding shellfish obtain sufficient nutrients and, under suitable water temperature conditions, reproduce, producing planktonic larvae. These planktonic larvae are released from the shellfish rearing module into the aquaculture pond, where they are dispersed by water currents and their own movement to the mud crab farming module, where they are preyed upon by the mud crabs.

[0081] Please see Figures 11 to 13 In an embodiment of the present invention, the energy utilization chain is as follows: large seaweed releases oxygen through photosynthesis to increase the dissolved oxygen content in the water, thereby meeting the oxygen consumption needs of mangrove roots and blue crabs and shellfish, and reducing the use of mechanical aeration equipment.

[0082] In this embodiment, through the operation of the aforementioned energy utilization chain, the large seaweed in the large seaweed aquaculture module utilizes light energy to convert carbon dioxide and water in the water into organic matter during photosynthesis, while simultaneously releasing oxygen into the water. This photosynthetic oxygen production process provides a continuous replenishment of dissolved oxygen to the aquaculture pond water. The increased dissolved oxygen content in the water meets the oxygen requirements for aerobic respiration of mangrove roots in the mangrove belt and mangrove planting island modules, as well as the oxygen requirements for respiratory metabolism of mud crabs in the mud crab aquaculture module and shellfish in the shellfish cultivation module. Because the large seaweed continuously replenishes dissolved oxygen to the water through photosynthesis, the dissolved oxygen level in the aquaculture pond water can be maintained within the design range, thereby reducing the frequency and duration of mechanical aeration equipment use, and lowering power consumption and equipment maintenance costs during the aquaculture process. Overall, this embodiment, through the photosynthesis of large seaweed, converts solar energy into chemical energy and releases oxygen, providing a sustainable energy input for the aquaculture system, effectively replacing mechanical energy with natural energy, and reducing the energy consumption and carbon emissions of the aquaculture system.

[0083] It should be noted that photosynthesis refers to the process by which green plants use light energy to synthesize organic matter from carbon dioxide and water and release oxygen. It is the most important energy fixation pathway in the Earth's ecosystem.

[0084] In its operation, during the daytime, under sunlight, the large algae in the floating algae layer on the surface can fully absorb sunlight and perform photosynthesis at a high rate, releasing a large amount of oxygen into the surface water, thus rapidly increasing the dissolved oxygen content. Simultaneously, the large algae in the underwater suspended algae layer utilize scattered light penetrating the water layer to perform photosynthesis in the middle and bottom layers, releasing oxygen into these layers as well, thus increasing the dissolved oxygen content in the bottom water as well. At night, without light, the large algae cease photosynthesis and oxygen release, but the dissolved oxygen accumulated during the day can still maintain the dissolved oxygen level of the water for a certain period. Mangrove roots are exposed to the air during low tide and can directly absorb oxygen from the atmosphere; during high tide, when submerged, they absorb dissolved oxygen from the water. Crabs and shellfish extract dissolved oxygen from the water through their gills for respiration and metabolism. When the photosynthetic oxygen release by the large algae is insufficient, the system can supplement it by introducing oxygen-rich seawater from the open sea through tidal water exchange, reducing the need for mechanical aeration equipment. When large seaweeds release sufficient oxygen through photosynthesis, mechanical aeration equipment should be kept off or operate at low power.

[0085] Please see Figures 11 to 13 In an embodiment of the present invention, the economic value chain is as follows: mud crabs are the main economic product for realizing aquaculture revenue; the carbon sinks of mangrove plants realize the monetization of ecological value through carbon trading or carbon credits; and large seaweed and shellfish are harvested and sold as secondary economic products.

[0086] In this embodiment, through the operation of the aforementioned economic value chain, mud crabs, as the main economic product of this aquaculture system, are harvested and sold after reaching marketable size following the aquaculture cycle, generating direct economic benefits. Mangrove plants in the mangrove belt module and mangrove planting island module fix atmospheric carbon dioxide through photosynthesis during their growth, forming a biomass carbon sink. This carbon sink amount can be quantified through remote sensing monitoring, sample plot surveys, or model calculations. The calculated carbon emission reductions can be traded on the carbon trading market as carbon trading products, or ecological compensation funds can be obtained through a carbon credit mechanism, thereby realizing the monetization of the mangrove ecological protection value. Large seaweed in the large seaweed aquaculture area module can be harvested after the aquaculture cycle and sold as food, feed, or biomass raw materials, forming secondary economic output. Shellfish in the shellfish cultivation area module can be selectively harvested after the aquaculture cycle and sold as aquatic products, also forming secondary economic output. By combining the above three or more economic output pathways, this aquaculture system has formed a diversified income structure, breaking through the traditional single-crop mud crab farming economic benefit model, and significantly improving the economic benefits per unit area while achieving ecological protection.

[0087] It should be noted that carbon sinks refer to the processes, activities, and mechanisms by which carbon dioxide is absorbed from the atmosphere through measures such as afforestation and vegetation restoration, thereby reducing the concentration of greenhouse gases in the atmosphere. Carbon trading refers to a market mechanism that trades carbon emission rights or carbon emission reductions as commodities. Carbon inclusion refers to quantifying and assigning value to the energy-saving and carbon-reduction behaviors of micro, small and medium-sized enterprises, communities, households, and individuals, and establishing a positive guidance mechanism that combines commercial incentives, policy encouragement, and certified emission reduction trading.

[0088] In the specific operation, after the breeding cycle ends, operators drain the breeding ponds. During the drainage process, fishing nets are set at the tidal sluice gate to harvest the mud crabs from the breeding ponds. The harvested mud crabs are graded according to size and packed into transport containers, then transported to the market for sale via cold chain logistics, realizing the breeding revenue of mud crabs. During or after the breeding cycle, large seaweed in the floating seaweed layer and the underwater hanging seaweed layer are harvested in batches. The harvested large seaweed is cleaned and processed and sold as food or feed ingredients. Filter-feeding shellfish in the shellfish cultivation module are selectively harvested. Selective harvesting means that some smaller shellfish are retained during harvesting to allow them to continue growing and maintain the population's reproductive capacity. The harvested shellfish are sold as aquatic products. Carbon sequestration is conducted on mangrove plants in the mangrove belt and mangrove planting island modules. The biomass method can be used, which involves measuring growth parameters such as diameter at breast height (DBH), tree height, and crown width of mangrove plants, estimating biomass using the allometric growth equation, and then calculating the carbon sequestration capacity of the mangrove plants based on the conversion factor between biomass and carbon storage. The carbon emission reductions obtained from this calculation are traded according to the relevant rules of the carbon trading market, or ecological compensation applications are submitted through a carbon credit platform to obtain carbon sequestration benefits.

[0089] In an embodiment of the present invention, the method further includes a step S34, which is set after step S30 and before step S40: Step S34: Set an ecosystem establishment period of 3 to 6 months to allow shellfish seedlings and large seaweeds to grow and reproduce during the ecosystem establishment period.

[0090] In this embodiment, an ecological establishment period of 3 to 6 months is established after the release of shellfish seedlings and macroalgae, but before the release of mud crab seedlings. This allows the shellfish seedlings and macroalgae to achieve sufficient growth and reproduction during this period. During the ecological establishment period, the shellfish seedlings grow to sexual maturity and begin to reproduce, producing a large number of planktonic larvae. These larvae form a sufficient population density in the water, providing abundant basic food for the subsequently released mud crabs. During the ecological establishment period, the macroalgae grow and form a stable algal community, achieving a stable level of photosynthetic oxygen production, continuously replenishing dissolved oxygen in the aquaculture pond. During the ecological establishment period, mangrove plants further establish and grow, expanding their root systems to form a richer three-dimensional spatial structure, providing a more complete shelter for the subsequently released mud crabs. After a 3-6 month ecological establishment period, the various biological components within the system have established preliminary ecological connections, and the material cycle and energy flow tend to stabilize. At this time, when mud crab seedlings are released, the mud crabs can obtain sufficient natural food and a suitable habitat, which is conducive to improving the survival rate and growth rate of the mud crabs.

[0091] It should be noted that the ecological establishment period refers to the time required from the completion of the introduction of shellfish and seaweed to the initial stabilization of the biological community within the system and the normal functioning of the ecological system.

[0092] In the specific operation process, after completing step S30 (release of shellfish seedlings and macroalgae), the operators do not intervene excessively in the system, only maintaining normal tidal water exchange and necessary environmental parameter monitoring, allowing the shellfish and macroalgae to grow and reproduce under natural conditions. During this period, the shellfish seedlings gradually grow into mature individuals, and the mature shellfish reproduce under suitable water temperature conditions, releasing a large number of fertilized eggs. The fertilized eggs hatch into planktonic larvae in the water, which then grow planktonicly, gradually increasing the population density. Macroalgae continue to grow during the ecological construction period, gradually accumulating biomass, and the seaweed layer coverage gradually reaches the design value. Mangrove plants complete their establishment during the ecological construction period, with new roots extending into the surrounding substrate. After a 3-6 month ecological construction period, the system is observed and evaluated to confirm that the shellfish have begun to reproduce and produce larvae, the macroalgae have formed a stable community, and the mangrove plants have survived and established themselves, before proceeding to step S40 (release of mud crab seedlings).

[0093] In an embodiment of the present invention, after step S60, the method further includes step S70: Step S70: Start the next breeding cycle. In the next breeding cycle, mud crab seedlings will be replenished through natural seeding or artificial seeding.

[0094] In this embodiment, after harvesting from one aquaculture cycle, the mangrove plants, shellfish, and large seaweed within the system continue to survive and grow. Shellfish continue to reproduce and produce larvae, while the large seaweed continues photosynthesis. In the next aquaculture cycle, mud crab seedlings can be replenished naturally, utilizing the tidal bore to allow planktonic larvae from the open sea to enter the aquaculture ponds via the tidal channel network and naturally settle within the system. Alternatively, mud crab seedlings can be replenished artificially, where operators purchase seedlings from external hatcheries and release them into the mud crab aquaculture module. After replenishing the mud crab seedlings naturally or artificially, the system can enter the next aquaculture cycle without the need to rebuild or re-introduce the basic biological components such as mangrove plants, shellfish, and large seaweed. Because the basic biological components such as mangrove plants, shellfish, and large seaweed have already formed a stable population within the system, the system can enter a stable operating state more quickly in the next aquaculture cycle, shortening the mud crab aquaculture cycle and thus improving the system's utilization efficiency and economic output.

[0095] It should be noted that natural seed introduction refers to the process of naturally introducing aquatic larvae from the open sea into aquaculture ponds using tidal currents; this is a common method of sourcing seedlings in intertidal aquaculture. Artificial seed introduction refers to the method of purchasing seedlings from external nurseries and then releasing them into aquaculture ponds.

[0096] In the specific operation process, after completing the harvest and carbon sequestration calculation in step S60, the operators determine the method of replenishing mud crab seedlings according to the farming plan for the next farming cycle. If the natural seedling introduction method is selected, during the mud crab breeding season in late spring and early summer, the gates are opened during the tidal surge when mud crab planktonic larvae are concentrated, according to tidal forecasts. This allows seawater containing mud crab planktonic larvae in the open sea to flow into the farming ponds through the tidal channel network. After entering the farming ponds with the water flow, the mud crab planktonic larvae inhabit and grow in sheltered environments such as mangrove roots and seaweed layers. If the artificial seedling introduction method is selected, the operators purchase healthy mud crab seedlings from the hatchery and release them into the mud crab farming area module according to the designed release density. After the mud crab seedlings are released, the system continues to operate according to step S50. The mud crabs feed on shellfish larvae as natural food and grow. Harvesting is carried out again after one farming cycle.

[0097] In embodiments of the present invention, the width of the mangrove belt along the shore is determined according to the height of the dike and the coastal wave conditions: when the dike height is 1.5 to 2.5 meters, the width of the mangrove belt is 3 to 5 meters; when the dike height is greater than or equal to 2.5 meters, the width of the mangrove belt is 5 to 10 meters; the trees in the mangrove belt are planted in a dense planting method with a row spacing of 1.5 to 2 meters and a plant spacing of 1 to 1.5 meters, so that the root system can form a continuous root network within 3 to 5 years.

[0098] In this embodiment, by linking the width of the mangrove belt along the shoreline with the height of the dike and coastal wave conditions, the design of the mangrove belt width is made more scientific and reasonable. When the dike height is low, the risk of the dike being eroded by sea waves is relatively small, and a mangrove belt with a width of 3 to 5 meters can meet the needs of soil stabilization and dike protection, avoiding excessive occupation of land space along the dike shoreline. When the dike height is high, the water-retaining pressure of the dike increases, and the risk of sea wave erosion also increases accordingly. A mangrove belt with a width of 5 to 10 meters can provide stronger soil stabilization and dike protection capabilities. A dense planting method with a row spacing of 1.5 to 2 meters and a plant spacing of 1 to 1.5 meters is adopted, ensuring that the mangrove plants maintain a relatively close distance both within and between rows, promoting the interweaving, connection, and intertwining of the mangrove root systems during growth. The mangrove root systems gradually grow and expand within 3 to 5 years after planting, with the root systems of adjacent plants connecting with each other, eventually forming a continuous underground root network. This continuous root network acts like a biological reinforcement layer on the embankment, binding the soil particles together into a unified whole, significantly improving the embankment's resistance to erosion and structural stability. Overall, this embodiment, through optimized design of the mangrove belt width and planting density, effectively conserves land resources while ensuring the effective functioning of the ecological barrier.

[0099] It should be noted that dense planting refers to planting mangroves at high density with small row and plant spacing, keeping the plants close together to promote the rapid interconnection of root systems and the formation of a continuous network. A continuous root network refers to the intertwining, connecting, and weaving of the root systems of adjacent mangrove plants during their growth, forming a network-like structure in the soil along the embankment.

[0100] In the specific operation, when constructing the aquaculture pond, the first step is to measure the top and bottom elevations of the dike and calculate its height. The width of the mangrove belt along the bank is determined based on the dike height: when the dike height is 1.5 to 2.5 meters, a planting area of ​​3 to 5 meters is reserved along the bank; when the dike height is greater than or equal to 2.5 meters, a planting area of ​​5 to 10 meters is reserved. Within the reserved planting area, lines are laid out and holes are dug according to a row spacing of 1.5 to 2 meters and a plant spacing of 1 to 1.5 meters. Mangrove seedlings are planted in the holes according to the laid-out lines, the soil is backfilled and compacted to ensure the seedlings are upright and stable. After planting, during the operation of the aquaculture pond, the mangrove plants grow in an environment of alternating tidal flooding and dew, and their root systems continuously extend deeper into the surrounding soil during their growth. The lateral roots of adjacent mangrove plants gradually approach and intertwine in the horizontal direction. After 3 to 5 years of growth, the root systems of adjacent plants connect in the soil to form a continuous network structure.

[0101] In an embodiment of the present invention, the stocking density of mud crabs in the mud crab farming area module is 0.5 to 2 crabs per square meter.

[0102] In this embodiment, by controlling the stocking density of mud crabs to between 0.5 and 2 crabs per square meter, the stocking density is maintained while avoiding competition among individuals due to overcrowding. This stocking density matches the reproductive capacity of the shellfish within the system, ensuring that the number of larvae produced by the shellfish meets the natural food needs of the mud crabs and reduces the amount of artificial feed required. Simultaneously, this stocking density provides sufficient space for individual mud crabs to move around, and the three-dimensional shelter provided by mangrove roots and seaweed effectively reduces the frequency and opportunity for encounters between individuals, minimizing aggression and cannibalism caused by competition for space, food, and mates, thus improving the survival rate of the mud crabs.

[0103] In embodiments of the present invention, the species of large seaweed cultivated is selected from at least one of Gracilaria, Asparagus officinalis, and kelp.

[0104] In this embodiment, Gracilaria, Gracilaria rubra, and kelp are all large seaweeds with high photosynthetic efficiency, capable of rapid growth and releasing large amounts of oxygen in aquaculture ponds. Gracilaria and Gracilaria rubra belong to the Rhodophyta phylum, exhibiting good tolerance to high temperatures and low light, making them suitable for cultivation in subtropical and tropical seas. Kelp belongs to the Phaeophyta phylum, suitable for cultivation in temperate seas with lower temperatures. All three types of large seaweed have high economic value. Gracilaria and Gracilaria rubra can be used as food ingredients or agar extraction raw materials, while kelp can be used as food or feed ingredients. After harvest, all can be sold as secondary economic products. By selecting these large seaweeds, the system achieves both oxygenation and nutrient absorption functions while increasing secondary economic output.

[0105] In embodiments of the present invention, the filter-feeding shellfish are selected from at least one of mussels, oysters, and razor clams.

[0106] In this embodiment, mussels, oysters, and razor clams are all common filter-feeding shellfish with high filtration efficiency and strong environmental adaptability. Mussels attach to solid substrates such as mangrove roots or tidal flats via their byssal threads, using water flow to filter water through their gills. Oysters attach to hard substrates with their left shell and filter suspended particles through their gills. Razor clams burrow in the mudflat substrate, extending their siphons to filter organic debris and phytoplankton from the water. All three shellfish thrive in mangrove aquaculture systems, and their resulting planktonic larvae provide excellent natural food for mud crabs. By selecting these shellfish, both biological water purification and a continuous natural food source for mud crabs are achieved, while also generating secondary economic output from shellfish.

[0107] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An ecologically coupled aquaculture system, characterized in that, The ecologically coupled aquaculture system is deployed in the intertidal zone with tidal exchange conditions, and the ecologically coupled aquaculture system includes: Mangrove belt modules are planted along the banks of the embankments of aquaculture ponds to form a continuous mangrove belt, which serves to stabilize the soil and protect the embankments, forming an ecological barrier and providing a source of litter for the aquaculture ponds. Mangrove planting island module, which is set in the internal area of ​​the aquaculture pond, is planted with mangrove plants; The tidal channel network module connects the aquaculture pond to the open sea and is used to regulate water quality through tidal exchange. A mud crab farming area module is set at least once in the root distribution area of ​​the mangrove planting island module, on both sides of the tidal channel network module, and in the root area of ​​the mangrove belt module, for releasing mud crabs; A shellfish cultivation module, located at least one of the following locations: the bottom of the tidal channel network, the root attachment area of ​​the mangrove plants, and the bottom area of ​​the cultivation pond, is used to cultivate filter-feeding shellfish; and The seaweed cultivation area module is set on the surface and lower layers of the water in the cultivation pond for the cultivation of large seaweed.

2. The ecologically coupled aquaculture system as described in claim 1, characterized in that, The seaweed cultivation area module includes a floating seaweed layer on the water surface and a suspended seaweed layer underwater. The seaweed layer on the water surface covers 20%-40% of the water area of ​​the cultivation pond, and the seaweed layer in the suspended underwater area covers 15%-30% of the water volume. And / or, the seaweed layer in the floating area on the water surface is used for shading and primary dissolved oxygen supply during the day, and the seaweed layer in the underwater suspended area is used for water oxygenation and nitrogen and phosphorus absorption, and forms a dissolved oxygen distribution in the vertical direction of the aquaculture water.

3. The ecologically coupled aquaculture system as described in claim 1, characterized in that, The filter-feeding shellfish cultivated in the shellfish cultivation area module produce larvae that serve as natural food for the mud crabs in the mud crab farming area module; the organic debris formed from the litter in the mangrove belt module after microbial decomposition serves as food for the filter-feeding shellfish.

4. The ecologically coupled aquaculture system as described in claim 1, characterized in that, In the spatial layout of the ecologically coupled aquaculture system, the mangrove belt module occupies 10%-20% of the total system area, the mangrove planting island module occupies 5%-15% of the total system area, the tidal channel network module occupies 10%-20% of the total system area, the mud crab farming area module occupies 20%-40% of the total system area, and the shellfish cultivation area module occupies 15%-20% of the total system area.

5. The ecologically coupled aquaculture system as described in claim 1, characterized in that, The planting density of mangrove plants on the mangrove planting island module is 1-5 plants per square meter; the tidal channel network module includes a main tidal channel and branch tidal channels, the width of the tidal channel is 1-5m and the depth is 0.5-2m, and the tidal channel network module is equipped with gates to control the exchange of water with the open sea.

6. An ecologically coupled aquaculture method, characterized in that, Ecologically coupled aquaculture is carried out using the ecologically coupled aquaculture system as described in any one of claims 1 to 5, the method comprising the following steps: Construct or modify aquaculture ponds in selected intertidal areas and divide them into modular functional zones to form mangrove belt modules, mangrove planting island modules, tidal channel network modules, mud crab aquaculture area modules, shellfish cultivation area modules, and seaweed aquaculture area modules. Mangrove plants are planted in the mangrove belt module and the mangrove planting island module to form an ecological barrier; Shellfish seedlings are introduced into the shellfish cultivation area module, and large seaweeds are introduced into the seaweed cultivation area module. Crab seedlings are released into the crab farming area module, and the crabs feed on the shellfish as natural food. During the breeding period, the system operates in a coordinated closed loop, forming a material cycle chain, an energy utilization chain, and an economic value chain, and regulates the parameters of the breeding environment. After the aquaculture is completed, the mud crabs are harvested, the large seaweed and shellfish are collected, and the carbon sequestration of the mangrove plants is calculated and evaluated.

7. The ecologically coupled aquaculture method as described in claim 6, characterized in that, The steps for regulating aquaculture environmental parameters include: The dissolved oxygen content in the aquaculture pond should be controlled at no less than 4.0 mg / L, the salinity should be controlled at 15-30 ppt, and the water temperature should be controlled at 20-33℃. The water level in the pond is controlled within 10-30 cm above the average elevation of the mangrove planting island module, and the aerial roots and breathing roots of the mangrove plants are intermittently exposed above the water surface.

8. The ecologically coupled aquaculture method as described in claim 6, characterized in that, The material cycle is as follows: nutrients in the excrement and uneaten food of mud crabs are absorbed and utilized by mangrove plants. After the dead branches and leaves of mangrove plants fall into the water, they are decomposed by microorganisms and transformed into natural food for shellfish, which are then consumed by mud crabs.

9. The ecologically coupled aquaculture method as described in claim 6, characterized in that, The energy utilization chain is as follows: large seaweed releases oxygen through photosynthesis to increase the dissolved oxygen content in the water, meeting the oxygen consumption needs of mangrove roots and crabs and shellfish, and reducing the use of mechanical aeration equipment.

10. The ecologically coupled aquaculture method as described in claim 6, characterized in that, The economic value chain is as follows: mud crabs are the main economic product for generating aquaculture revenue; mangrove carbon sinks are monetized through carbon trading or carbon credits; and large seaweed and shellfish are harvested and sold as secondary economic products.

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