Method for breeding scylla paramamosain by mangrove forest

Abstract

The invention relates to the technical field of ecological breeding of scylla paramamosain and protection and restoration of mangrove forests. The invention provides a method for culturing scylla paramamosain by using mangrove forest, which comprises the following steps: (1) carrying out simple engineering transformation on the basis of a coastal wetland traditional culture pond, constructing a planting island in the middle of the culture pond, and reserving an annular tidal creek between the planting island and the periphery of the culture pond; (2) planting mangrove plants in the planting island to form a man-made forest; (3) small aquatic plants are planted at the bottom of the artificial forest, and large algae are planted in the annular ditches; and (4) putting the young blue crabs into the culture pond, and carrying out daily management until the blue crabs are harvested. The shellfish is used for providing main food supply for the blue crabs, and meanwhile water is purified; excrement of the blue crabs can be fed back to promote growth of mangroves, algae, mussels and the like; large algae can perform photosynthesis at the bottom of the pond to increase dissolved oxygen in water, and small sea grass is placed in the planting island to make up for the defect of low coverage of newly planted mangrove forest plant seedlings.

Description

Technical Field

[0001] The invention relates to the technical field of ecological breeding of mud crabs and protection and restoration of mangroves, and in particular to a method for breeding mud crabs by utilizing mangroves. Background Art

[0002] The mud crab, also known as the blue crab, red sturgeon, mud crab, or mud crab, is an arthropod of the family Portunidae, order Decapoda. It typically weighs 300-500g. Its cephalothorax is oval, with a dorsal protuberance and an H-shaped pattern. Its surface is smooth. Its body is bluish-green, without small protrusions or white spots. Its chelipeds are stout and asymmetrical, with the right larger than the left. The latticework markings on the chelipeds and legs are less numerous and lighter in color. The male abdomen is divided into five segments, with segments 3-5 fused to form a broad triangle. The female abdomen has seven segments, which are broadly oval and may or may not have a latticework pattern.

[0003] The mud crab, the largest and fastest-growing member of the family Portunidae, is a prized marine crab and a traditional aquatic export. Its meat is delicious and highly nutritious, earning it the reputation of "sea ginseng," making it a highly sought-after and prized seafood. Mud crabs are highly disease-resistant and resistant to drought and exposure, making them suitable for long-distance transportation and a stable market.

[0004] At present, in the production process of mud crab farming, most of them are simply reused shrimp ponds and fish ponds to carry out mud crab monoculture or polyculture. The monoculture model of mud crab is to reuse extensive farming, and the polyculture model is to reuse shrimp ponds or fish ponds to mainly culture Vannamei shrimp or tilapia, and to culture a small amount of mud crab as a supplement. What is more serious is that a good farming model has not yet been developed for mud crab farming, and there are bottlenecks in farming technology. In addition, mud crabs have ferocious habits, and individuals attack and cannibalize each other under conditions without protective facilities. This directly leads to low survival rate and low output of mud crabs under the two farming models.

[0005] Therefore, it is particularly important to explore a more ecological and higher survival rate breeding method. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for cultivating mud crabs using mangroves. The present invention artificially constructs mangroves and combines them with other plants to purify water quality while providing shade and shelter for the growth of mud crabs and a small amount of food supply, thereby reducing the cannibalism rate among the mud crabs.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for cultivating mud crabs using mangroves, comprising the following steps:

[0009] (1) Based on the simple engineering transformation of the traditional aquaculture pond in the coastal wetland, a planting island is constructed in the middle of the aquaculture pond, and a circular tidal ditch is reserved between the planting island and the surrounding area of ​​the aquaculture pond;

[0010] (2) Planting mangroves on the plantation islands to form artificial forests;

[0011] (3) Plant small aquatic plants at the bottom of the plantation and large algae in the annular ditch;

[0012] (4) Release the blue crab seedlings into the breeding pond and carry out daily management until the blue crabs are harvested.

[0013] Preferably, the depth of the aquaculture pond in step (1) relative to the banks around the aquaculture pond is 2.5 to 3.5 m, and the slope of the edge of the aquaculture pond is 45 to 65 degrees.

[0014] Preferably, the length of the planting island in step (1) is 10 to 80 m, the width is 8 to 50 m, the height of the planting island relative to the bottom of the annular tidal channel in the culture pond is 1.0 to 1.5 m, and the slope around the planting island is 30 to 60 degrees.

[0015] Preferably, the width of the annular tidal ditch in step (1) is 4.5 to 8 m, and the annular tidal ditch is further provided with 1 to 2 water inlets and outlets for exchanging seawater with the outside and taking in nutrients. The ratio of the width of the water inlets and outlets to the water area is set at 50 to 80 cm / hectare.

[0016] Preferably, the species of the mangrove plants in step (2) is one or more of Avicennia marina, Kandelia candel, Tung blossom tree, Rhizophora rubra, Sea lotus, Bruguiera gymnorrhiza, Caryophyllum nobile, and Sonneratia salsa, and the mangrove plants are planted with a plant spacing of 1.0 to 2.0 m and a row spacing of 1.0 to 2.0 m.

[0017] Preferably, the species of the small aquatic plants in step (3) is seahorse teeth, and the planting density of the seahorse teeth is 5 to 10 plants / m 2 The species of the macroalgae is Gracilaria, and the density of the Gracilaria is 1.5 to 3.0 kg wet weight / m 2 .

[0018] Preferably, a floating bed is provided in the annular ditch, in which kelp and wakame are planted, and the area of ​​a single floating bed is 0.3 to 1 m 2 The floating bed is arranged every 10 to 15 m 2 The density of one floating bed is set on the water surface.

[0019] Preferably, the specification of the blue crab seedlings in step (4) is 20-50 g / each, and the release amount is 800-900 / mu.

[0020] Preferably, the daily management in step (4) includes feeding shellfish and water management;

[0021] The shellfish are mussels and blue clams, and the blue crabs are fed according to the standard of 15 to 20 kg per mu per day, and fish meal, meat and bone meal, shrimp meal, soybean cake or soybean meal, rice flour, flour, and three-cornered grass powder are supplemented.

[0022] The water volume management method comprises: utilizing the water inlet and outlet to control the water level in the culture pond; and based on the natural tidal pattern, exchanging water with the open sea water on the first and fifteenth day of each lunar month and 2 to 3 days before and after. The amount of water exchanged each time accounts for 20 to 40% of the total water volume of the pond. When the water level is high, the water in the culture pond is controlled to submerge the planting island by 5 to 15 cm; and when the water level is low, the water level in the annular ditch is ensured to be no less than 80 cm.

[0023] The present invention provides a method for breeding mud crabs using mangroves, comprising the following steps: (1) performing simple engineering transformation on a traditional breeding pond in a coastal wetland, constructing a planting island in the middle of the breeding pond, and reserving a circular tidal ditch between the planting island and the four sides of the breeding pond; (2) planting mangrove plants in the planting island to form an artificial forest; (3) planting small aquatic plants at the bottom of the artificial forest and planting large algae in the circular ditch; (4) releasing mud crab seedlings into the breeding pond and carrying out daily management until the mud crabs are harvested. The present invention uses mangroves, algae and aquatic plants to jointly purify the water quality of the breeding pond and provide shade and shelter for blue crabs; shellfish provide the main food supply for blue crabs and purify the water quality at the same time; the excrement of blue crabs can feed back and promote the growth of mangroves, algae, mussels, etc.; large algae (such as Gracilaria) can carry out photosynthesis at the bottom of the pond, increase the dissolved oxygen in the water, and avoid blue crabs from dying of lack of oxygen in the high temperature season in summer; small seaweeds (such as seahorses) are placed on the planting islands to make up for the low coverage of newly planted mangrove seedlings and the inability to provide effective shade for blue crabs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Scene 1 of harvesting adult crabs after draining the pond tidal gully;

[0025] Figure 2 Scene 2 of harvesting adult crabs after draining the pond tidal gully;

[0026] Figure 3 Adult crabs and Gracilaria seen after draining the pond tidal gully;

[0027] Figure 4 This is a picture of the pond's daily low water level scene (the water level is 20-40cm lower than the planting island);

[0028] Figure 5 This is the normal water level scene diagram of the pond (the water level is flush with the planting island);

[0029] Figure 6 This is a picture of the pond's daily high water level scene (the water level is 10-30cm higher than the planting island). DETAILED DESCRIPTION

[0030] The present invention provides a method for cultivating mud crabs using mangroves, comprising the following steps:

[0031] (1) Based on the simple engineering transformation of the traditional aquaculture pond in the coastal wetland, a planting island is constructed in the middle of the aquaculture pond, and a circular tidal ditch is reserved between the planting island and the surrounding area of ​​the aquaculture pond;

[0032] (2) Planting mangroves on the plantation islands to form artificial forests;

[0033] (3) Plant small aquatic plants at the bottom of the plantation and large algae in the annular ditch;

[0034] (4) Release the blue crab seedlings into the breeding pond and carry out daily management until the blue crabs are harvested.

[0035] In the present invention, the depth of the aquaculture pond in step (1) relative to the surrounding banks of the aquaculture pond is preferably 2.5 to 3.5 m, more preferably 3 m, and the slope of the edge of the aquaculture pond is preferably 45 to 65 degrees, more preferably 55 degrees.

[0036] In the present invention, the length of the planting island in step (1) is preferably 10 to 80 m, more preferably 40 to 50 m, the width is preferably 8 to 50 m, more preferably 20 to 25 m, the height of the planting island relative to the bottom of the annular tidal channel in the culture pond is preferably 1.0 to 1.5 m, more preferably 1.2 to 1.3 m, and the slope around the planting island is preferably 30 to 60 degrees, more preferably 40 to 50 degrees.

[0037] In the present invention, the width of the annular tidal ditch in step (1) is preferably 4.5 to 8 m, more preferably 5 to 6 m. The annular tidal ditch is preferably provided with 1 to 2 water inlets and outlets to exchange seawater with the outside and to take in nutrients. The ratio of the width of the water inlets and outlets to the water area is preferably set to 50 to 80 cm / hectare, more preferably 60 to 70 cm / hectare.

[0038] In the present invention, the species of the mangrove plants in step (2) are preferably one or more of Avicennia marina, Kandelia candel, Tung blossom tree, Rhizophora rubra, Sea lotus, Bruguiera gymnorrhiza, Cercidiphyllum serrata, and Sonneratia salsa. The plant spacing of the mangrove plants during planting is preferably 1.0 to 2.0 m, more preferably 1.5 m, and the row spacing is preferably 1.0 to 2.0 m, more preferably 1.5 m.

[0039] In the present invention, the species of the small aquatic plants in step (3) is preferably seahorse teeth, and the planting density of the seahorse teeth is preferably 5 to 10 plants / m 2 , more preferably 7 to 8 plants / m 2 The species of the macroalgae is preferably Gracilaria, and the density of the Gracilaria is preferably 1.5 to 3.0 kg wet weight / m 2 , more preferably 2 to 2.5 kg wet weight / m 2 .

[0040] In the present invention, the annular ditch is preferably further provided with a floating bed, in which kelp and wakame are planted, and the area of ​​a single floating bed is preferably 0.3 to 1 m 2 , more preferably 0.5 to 0.6 m 2 The floating bed is preferably arranged in a manner of 10 to 15 m 2 It is further preferred to configure the water surface with a density of 1 floating bed.

[0041] In the present invention, the specification of the blue crab seedlings in step (4) is preferably 20-50 g / bird, more preferably 30-40 g / bird, and the release amount is preferably 800-900 birds / acre, more preferably 850 birds / acre.

[0042] In the present invention, the daily management in step (4) preferably includes feeding shellfish and water management;

[0043] The shellfish are preferably mussels and blue clams, and the blue crabs are preferably fed at a rate of 15 to 20 kg per mu per day, more preferably 17 to 18 kg per mu, and supplemented with fish meal, meat and bone meal, shrimp meal, bean cake or soybean meal, rice flour, flour, and smilax glabra powder.

[0044] The water volume management method is preferably as follows: the water level in the breeding pond is controlled by using the water inlet and outlet, and based on the natural tidal law, the water is exchanged with the sea water on the first and fifteenth day of each lunar month and 2 to 3 days before and after, the amount of water exchanged each time accounts for 20 to 40% of the total water volume of the pond, when the water level is high, the water in the breeding pond is controlled to submerge the planting island by 5 to 15 cm, and when the water level is low, the water level in the annular ditch is ensured to be not less than 80 cm. Further preferably, the water level in the breeding pond is controlled by using the water inlet and outlet, and based on the natural tidal law, the water is exchanged with the sea water on the first and fifteenth day of each lunar month and 3 days before and after, the amount of water exchanged each time accounts for 30% of the total water volume of the pond, when the water level is high, the water in the breeding pond is controlled to submerge the planting island by 10 cm, and when the water level is low, the water level in the annular ditch is ensured to be not less than 90 cm.

[0045] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0046] Example 1

[0047] A method for cultivating mud crabs using mangroves comprises the following steps:

[0048] (1) Simple engineering transformation of traditional aquaculture ponds in coastal wetlands was carried out, so that the depth of the aquaculture pond relative to the surrounding shore was 2.5m, the slope of the edge was 65 degrees, and a planting island 10m long and 8m wide was built in the middle of the aquaculture pond. A 4.5m wide circular tidal ditch was reserved between the planting island and the surrounding of the aquaculture pond. The height of the planting island relative to the bottom of the circular tidal ditch in the aquaculture pond was 1.0m, and the slope around the planting island was 60 degrees.

[0049] The circular tidal ditch is also equipped with an inlet and outlet to exchange seawater with the outside and take in nutrients. The ratio of the width of the inlet and outlet to the water area of ​​the pond is set at 80cm / hectare.

[0050] (2) Plant mangroves in the planting islands with a plant spacing of 1.0 m and a row spacing of 1.0 m to form an artificial forest;

[0051] (3) At the bottom of the artificial forest, 10 trees / m 2 Plant seahorse teeth in the annular groove according to the standard of 1.5kg wet weight / m 2 Gracilaria is planted according to the standard. A floating bed is set in the annular ditch. Kelp and wakame are planted in the floating bed. The area of ​​a single floating bed is 0.3m 2 Floating bed is per 10m 2 The density of one floating bed is configured on the water surface;

[0052] (4) 50g / squid blue crab seedlings were placed into the culture pond at a rate of 800 crabs / mu, and the blue crabs were fed with mussels and blue clams at a rate of 20kg / mu per day, and supplemented with fish meal, meat and bone meal, shrimp meal, soybean cake or soybean meal, rice flour, flour, and three-cornered grass meal;

[0053] The water level in the breeding pond is controlled by the inlet and outlet. Based on the natural tidal law, the water is exchanged with the open sea water on the first and fifteenth day of each lunar month and the two days before and after. The amount of water exchanged each time accounts for 20% of the total water volume of the pond. When the water level is high, the water in the breeding pond is controlled to submerge the planting island by 15 cm. When the water level is low, the water level in the circular ditch is guaranteed to be no less than 80 cm until the blue crabs are harvested.

[0054] Note: The mangrove plants used in this embodiment are planted in combination with a variety of plants such as Avicennia marina, Kandelia candel, Tung blossom tree, Rhizophora rubra, Helianthus annuus, Bruguiera gymnorrhiza, Caryophyllum serrata, and Sonneratia salsa to improve the ecological diversity in the pond.

[0055] Example 2

[0056] A method for cultivating mud crabs using mangroves comprises the following steps:

[0057] (1) Simple engineering transformation of traditional aquaculture ponds in coastal wetlands was carried out, so that the depth of the aquaculture pond relative to the surrounding shore was 3.5m, the slope of the edge was 45 degrees, and a planting island 80m long and 50m wide was built in the middle of the aquaculture pond. An 8m wide circular tidal ditch was reserved between the planting island and the surrounding of the aquaculture pond. The height of the planting island relative to the bottom of the circular tidal ditch in the aquaculture pond was 1.5m, and the slope around the planting island was 30 degrees.

[0058] Two inlets and outlets are also set up in the circular tidal ditch to exchange seawater with the outside and take in nutrients. The ratio of the width of the inlet and outlet to the water area in the pond is set at 50cm / hectare.

[0059] (2) Plant mangroves in the planting islands with a plant spacing of 2.0 m and a row spacing of 2.0 m to form an artificial forest;

[0060] (3) At the bottom of the artificial forest, 5 trees / m 2 The standard planting of seahorse teeth was carried out in the annular groove according to 3.0 kg wet weight / m 2 Gracilaria is planted according to the standard. A floating bed is set in the annular ditch. Kelp and wakame are planted in the floating bed. The area of ​​a single floating bed is 1m 2 Floating bed is per 15m 2 The density of one floating bed is configured on the water surface;

[0061] (4) 30g / squid crab seedlings were placed into the culture pond at a rate of 900 crabs / mu, and the crabs were fed with mussels and blue clams at a rate of 15kg / mu per day, and supplemented with fish meal, meat and bone meal, shrimp meal, soybean cake or soybean meal, rice flour, flour, and three-cornered grass meal;

[0062] The water level in the breeding pond is controlled by the inlet and outlet. At the same time, based on the natural tidal law, the water is exchanged with the open sea water on the first and fifteenth day of each lunar month and the three days before and after. The amount of water exchanged each time accounts for 40% of the total water volume of the pond. When the water level is high, the water in the breeding pond is controlled to submerge the planting island by 5 cm. When the water level is low, the water level in the circular ditch is guaranteed to be no less than 80 cm until the blue crabs are harvested.

[0063] Note: The mangrove plants used in this embodiment are planted in combination with a variety of plants such as Avicennia marina, Kandelia candel, Tung blossom tree, Rhizophora rubra, Helianthus annuus, Bruguiera gymnorrhiza, Caryophyllum serrata, and Sonneratia salsa to improve the ecological diversity in the pond.

[0064] Example 3

[0065] A method for cultivating mud crabs using mangroves comprises the following steps:

[0066] (1) Simple engineering transformation of traditional aquaculture ponds in coastal wetlands was carried out, so that the depth of the aquaculture pond relative to the surrounding shore was 3m, the slope of the edge was 55 degrees, and a planting island 60m long and 30m wide was built in the middle of the aquaculture pond. A 6m wide circular tidal ditch was reserved between the planting island and the surrounding of the aquaculture pond. The height of the planting island relative to the bottom of the circular tidal ditch in the aquaculture pond was 1.2m, and the slope around the planting island was 45 degrees.

[0067] Two inlets and outlets are also set up in the circular tidal ditch to exchange seawater with the outside and take in nutrients. The ratio of the width of the inlet and outlet to the water area in the pond is set at 60cm / hectare.

[0068] (2) Plant mangroves in the planting islands with a plant spacing of 1.5 m and a row spacing of 1.5 m to form an artificial forest;

[0069] (3) At the bottom of the artificial forest, 8 trees / m 2 Plant seahorse teeth in the annular groove according to the standard of 2.5kg wet weight / m 2 Gracilaria is planted according to the standard. A floating bed is set in the annular ditch. Kelp and wakame are planted in the floating bed. The area of ​​a single floating bed is 0.5m 2 Floating bed is per 12m 2 The density of one floating bed is configured on the water surface;

[0070] (4) 40g / squid blue crab seedlings were placed into the culture pond at a rate of 850 crabs / mu, and the blue crabs were fed with mussels and blue clams at a rate of 18kg / mu per day, and supplemented with fish meal, meat and bone meal, shrimp meal, soybean cake or soybean meal, rice flour, flour, and three-cornered grass meal;

[0071] The water level in the breeding pond is controlled by the inlet and outlet. Based on the natural tidal law, the water is exchanged with the open sea water on the first and fifteenth day of each lunar month and the three days before and after. The amount of water exchanged each time accounts for 30% of the total water volume of the pond. When the water level is high, the water in the breeding pond is controlled to submerge the planting island by 10 cm. When the water level is low, the water level in the circular ditch is guaranteed to be no less than 80 cm until the blue crabs are harvested.

[0072] Note: The mangrove plants used in this embodiment are planted in combination with a variety of plants such as Avicennia marina, Kandelia candel, Tung blossom tree, Rhizophora rubra, Helianthus annuus, Bruguiera gymnorrhiza, Caryophyllum serrata, and Sonneratia salsa to improve the ecological diversity in the pond.

[0073] Test example

[0074] From April 2020 to November 2024, a mud crab farming experiment was conducted in Leizhou, Zhanjiang City, Guangdong Province. The methods of Examples 1 to 3 were used for modification and farming tests, and three test plots were selected for each example for repeated testing. The farming time was calculated from the day of release and ended when the crabs reached the specifications of commercial crabs (pickled crablets 100-200g, crab roe 200g or more, and butter crabs 150g or more). The average per mu yield of Examples 1 to 3 (net increase after deducting the initial release amount) was also calculated. The results are shown in Table 1.

[0075] Table 1

[0076] Group Experimental group 1 Experimental Group 2 Experimental Group 3 Initial dosage (kg / mu) 40 27 34 Harvest (kg / mu) 82.75 66.08 77.92 Average yield (kg / mu) 42.75 39.08 43.92 Feeding time (kg / mu) 98 127 112

[0077] Conclusion: The aquaculture method of this invention provides a complete living system for blue crabs by combining mangroves, algae, mussels, and other organisms. Commercial blue crab aquaculture can be achieved in approximately 3-4 months, with an average yield of 37-45 kg per mu per breeding. Two commercial aquacultures can be completed annually, with an average annual yield of 75-90 kg per mu.

[0078] While the initial costs of mangrove planting and pond renovation are increased, the improved environment allows for continuous use and results in higher yields per mu. Furthermore, because the rearing environment is closer to the natural one, with less human intervention during the rearing process, the mud crabs raised in the mangrove ecosystem of this invention are superior in quality and flavor to those raised in conventional ponds, making them more popular in the market.

[0079] As can be seen from the above embodiments, the present invention provides a method for cultivating mud crabs using mangroves, comprising the following steps: (1) performing simple engineering transformation based on traditional aquaculture ponds in coastal wetlands, constructing a planting island in the middle of the aquaculture pond, and reserving a circular tidal ditch between the planting island and the surrounding area of ​​the aquaculture pond; (2) planting mangrove plants in the planting island to form an artificial forest; (3) planting small aquatic plants at the bottom of the artificial forest and planting large algae in the annular ditch; (4) placing mud crab seedlings into the aquaculture pond and performing daily management until the mud crabs are harvested. The present invention utilizes shellfish to provide the main food supply for mud crabs and purify the water quality at the same time; mud crab excrement can feed back and promote the growth of mangroves, algae, mussels, etc.; large algae can photosynthesize at the bottom of the pond to increase dissolved oxygen in the water body, and small seaweeds are placed on the planting island to make up for the low coverage of newly planted mangrove plant seedlings.

[0080] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for cultivating mud crabs using mangroves, characterized in that: The steps include: (1) Based on the simple engineering transformation of the traditional aquaculture pond in the coastal wetland, a planting island is constructed in the middle of the aquaculture pond, and a circular tidal ditch is reserved between the planting island and the surrounding area of ​​the aquaculture pond; (2) Planting mangroves on the plantation islands to form artificial forests; (3) Plant small aquatic plants at the bottom of the plantation and large algae in the annular ditch; (4) Release the blue crab seedlings into the breeding pond and carry out daily management until the blue crabs are harvested.

2. The method according to claim 1, characterized in that The depth of the breeding pond in step (1) relative to the bank foundation around the breeding pond is 2.5 to 3.5 meters, and the slope of the breeding pond edge is 45 to 65 degrees.

3. The method according to claim 2, characterized in that The length of the planting island in step (1) is 10 to 80 m, the width is 8 to 50 m, the height of the planting island relative to the bottom of the annular tidal channel in the culture pond is 1.0 to 1.5 m, and the slope around the planting island is 30 to 60 degrees.

4. The method according to claim 3, characterized in that The width of the annular tidal ditch in step (1) is 4.5 to 8 meters. The annular tidal ditch is also provided with 1 to 2 water inlets and outlets to exchange seawater with the outside and take in nutrients. The ratio of the width of the water inlet and outlet to the water area is set to 50 to 80 cm / hectare.

5. The method according to claim 1, wherein The species of the mangrove plants in step (2) are one or more of Avicennia marina, Kandelia candel, Tung blossom tree, Rhizophora rubra, Sea lotus, Bruguiera gymnorrhiza, Caryophyllum serrata, and Sonneratia salsa. The mangrove plants are planted at a plant spacing of 1.0 to 2.0 m and a row spacing of 1.0 to 2.0 m.

6. The method according to claim 5, characterized in that The species of the small aquatic plants in step (3) is seahorse teeth, and the planting density of the seahorse teeth is 5 to 10 plants / m 2 The species of the macroalgae is Gracilaria, and the density of the Gracilaria is 1.5 to 3.0 kg wet weight / m 2 .

7. The method according to claim 6, characterized in that The annular ditch is also provided with a floating bed, in which kelp and wakame are planted. The area of ​​a single floating bed is 0.3 to 1 m 2 The floating bed is arranged every 10 to 15 m 2 The density of one floating bed is set on the water surface.

8. The method according to claim 1, characterized in that The specification of the blue crab seedlings described in step (4) is 20-50g / each, and the release amount is 800-900 / mu.

9. The method according to claim 8, characterized in that The daily management in step (4) includes feeding shellfish and water management; The shellfish are mussels and blue clams, and the blue crabs are fed according to the standard of 15 to 20 kg per mu per day, and fish meal, meat and bone meal, shrimp meal, soybean cake or soybean meal, rice flour, flour, and three-cornered grass powder are supplemented. The water volume management method comprises: utilizing the water inlet and outlet to control the water level in the culture pond; and based on the natural tidal pattern, exchanging water with the open sea water on the first and fifteenth day of each lunar month and 2 to 3 days before and after. The amount of water exchanged each time accounts for 20 to 40% of the total water volume of the pond. When the water level is high, the water in the culture pond is controlled to submerge the planting island by 5 to 15 cm; and when the water level is low, the water level in the annular ditch is ensured to be no less than 80 cm.

Images