Stereoscopic estuary fishery habitat restoration device and investigation and evaluation method

Abstract

The invention discloses an estuary fishery habitat restoration three-dimensional device and an investigation and evaluation method, and relates to the technical field of fishery ecological restoration, the device comprises the following components: a plant floating bed area, a pipeline reef body area, a gabion net cage area and a device frame; by constructing the three-dimensional repairing device comprising the plant floating bed area, the pipeline reef body area and the gabion net cage area, diversified inhabitation environments are provided for different types of aquatic organisms, the plant floating bed area can purify water and can provide a rest place for birds, meanwhile, the root system of the plant floating bed area provides an attachment matrix for eggs and larvae, and the survival rate of the birds is improved. The pipeline reef body area provides a hiding and sheltering place for fishes and other aquatic organisms, attaching organisms such as oysters and barnacles can be attached on the pipe wall, the gabion net cage area provides a suitable habitat for shrimps, crabs and various benthic organisms, and the three-dimensional habitat repairing device is beneficial to improving the ecological diversity of the estuary fishery habitat and improving the ecological environment of the estuary fishery habitat. And better habitat conditions are provided for various aquatic organisms.

Description

Technical Field

[0001] The invention relates to the technical field of fishery ecological restoration, in particular to a three-dimensional device for restoring estuary fishery habitat and a survey and evaluation method. Background Art

[0002] Estuarine fishery habitat is an important part of the ecosystem. It not only provides habitats for many aquatic organisms, but also plays a key role in maintaining ecological balance and human fishery activities. However, with the continuous increase in human activities, the ecological environment in the estuary area has been severely damaged, and the fishery habitat has gradually degraded, leading to a decline in biodiversity and a reduction in fishery resources. In order to cope with this problem, fishery ecological restoration technology has emerged, aiming to restore and improve estuarine fishery habitats through scientific methods.

[0003] Although traditional three-dimensional restoration devices can improve fishery habitats to a certain extent, they still have some obvious shortcomings. They lack comprehensive consideration of the habitat needs of different types of aquatic organisms. Although gabion cage areas can provide habitats for shrimps, crabs and benthic organisms, they lack flexibility and adaptability, especially in silted estuaries. It is easy for the cages to be silted up and lose their function of providing habitats, making it difficult to meet the needs of dynamically changing biological communities.

[0004] In summary, traditional fishery ecological restoration technology has certain limitations in the restoration of estuarine fishery habitats. In order to overcome these shortcomings, the present invention proposes a three-dimensional device for estuarine fishery habitat restoration and an investigation and evaluation method, which is particularly important. Summary of the invention

[0005] The purpose of the present invention is to make up for the shortcomings of the existing technology and provide a three-dimensional device for restoring estuarine fishery habitats and a survey and evaluation method. It can provide a diverse habitat for different types of aquatic organisms by constructing a three-dimensional restoration device including a plant floating bed area, a pipeline reef area and a gabion cage area, and accurately evaluate the restoration effect through a systematic survey and evaluation method, so as to achieve comprehensive restoration and improvement of estuarine fishery habitats.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a three-dimensional device for restoring estuary fishery habitats, the device comprising a plant floating bed area, a pipeline reef area, a gabion cage area and a stainless steel frame structure (5):

[0007] The plant floating bed area (1) comprises: a foam float (701), an angle iron (702), screw holes (703) on the angle iron for fixing the floating bed, a plant root system (704), and a polyethylene mesh (705);

[0008] The pipeline reef area (2) comprises: a stainless steel frame (201), a PVC pipe (202), a first nylon rope (203), and a hole (204) opened on the PVC pipe;

[0009] The gabion box area (3) comprises: a stainless steel frame (301), a wire cage (302), and stones (303);

[0010] Plant floating bed area: located on the upper part of the stainless steel frame device, it is composed of foam floats, stainless steel pipe frames and floating bed plant modules. The upper part of the stainless steel frame is welded into 9 squares by angle irons, and floating bed plant modules are placed in each square. The modules and the frame are fixed with screws through the holes on the angle irons. The floating bed plant module consists of two layers of polyethylene mesh and plant roots filled in the middle, which are clamped and fastened with plastic tie bands. The entire floating bed frame is nested in the stainless steel frame, located at the top of the frame, and connected to the frame by nylon ropes. The foam floats around enable the floating bed to float up and down with the tide without leaving the frame. Plant growth can purify the water. The surface of the floating bed provides a resting place for birds, and the roots provide an attachment matrix for fish eggs and fry. The filling ratio of plant roots in the floating bed plant module is determined by the following formula: Where P is the filling ratio of plant roots, V r is the total volume of plant roots, V m is the total volume of the floating bed plant module. The total volume of the plant root system is obtained by measuring the product of the average volume of a single plant root system and the number of plant roots in the module. The total volume of the floating bed plant module is calculated based on the size of the module.

[0011] Pipeline reef area: Located in the middle of the stainless steel frame device and above the gabion cage, 5 PVC pipes of different diameters are placed in the 16 squares on the upper part of the frame, one group in each square, fixed to the frame with nylon ropes. This area can provide hiding and shelter for fish and aquatic organisms, and attached organisms can grow on the pipe wall. The density of hole distribution on the PVC pipe is calculated according to the following formula: Where D is the hole distribution density, n is the number of holes on a single PVC pipe, r is the radius of the PVC pipe, L is the length of the PVC pipe, and the number of holes on a single PVC pipe is set according to the ecological function requirements of PVC pipes of different pipe diameters;

[0012] Gabion cage area: A gabion cage area is set at the bottom of the stainless steel frame device. An independent cage net is made of wire cages. Each cage net is filled with stones of different specifications. Four cage nets are filled with each specification, totaling 16 cage nets, which are randomly placed in 16 small squares at the bottom of the frame device. Removable cross bars are set around the frame. The cage provides a suitable habitat for shrimps, crabs and various benthic organisms. The filling layout of stones of different specifications in the gabion cage adopts a hierarchical random filling algorithm. The specific steps are as follows: First, the gabion cage is divided into several small units of volume. For each specification of stone, a small unit is randomly selected for filling. The filling ratio of stones of different specifications in the gabion cage is calculated according to the following formula: Where R i is the filling ratio of the i-th specification stone, N i is the number of stones of the i-th specification, N t The total number of stones in the gabion box, which is determined by the volume of the box, the specifications of the stones and the habitat requirements of the organisms;

[0013] Stainless steel frame structure: A stainless steel welded frame is used as a fixing device, and a steel plate is welded at the bottom as a base to prevent it from sinking into the sediment. Steel pipes are welded horizontally and vertically at heights of 0.25m and 0.75m with intervals of 50cm to form 16 small squares of 50cm×50cm. The entire frame is connected to anchors with nylon ropes around it to fix the device in the intertidal zone of the estuary to prevent it from being knocked down by typhoon extreme weather. The welding process of the frame adopts a staggered welding method. First, the horizontal steel pipe and the vertical steel pipe are spot-welded at each intersection, and then starting from one corner of the frame, continuous welding is performed in a specific order. After each welding distance, an intersection is skipped and welding is continued. The determination of this welding sequence is obtained through the force analysis of the frame under the impact of water flow and wind and waves. It has been verified by simulation experiments that it can effectively improve the impact resistance of the frame.

[0014] Furthermore, the selection of plant roots in the floating bed plant module is based on the water quality conditions and biological attachment requirements of the estuary intertidal zone, specifically:

[0015] An ecological function analysis was conducted on the roots of common aquatic plants in the intertidal zone of the estuary, including their ability to absorb nitrogen and phosphorus nutrients in the water and their stability in providing attachment for fish eggs and larvae. An ecological function evaluation model for plant roots was established. The evaluation indicators included root surface area, root hair density, and secretion composition. Data for each evaluation indicator were obtained through field sampling and laboratory analysis of the roots of a variety of plants. The weight of each evaluation indicator was determined using the analytic hierarchy process, for example, the weight of the root surface area was 0.4, the weight of the root hair density was 0.3, and the weight of the secretion composition was 0.3. The comprehensive ecological function value of each plant root was calculated based on the evaluation model, and a combination of plant roots with higher comprehensive ecological function values ​​was selected for the floating bed plant module. The combination was matched according to the characteristics of different plant roots, for example, a root system with strong adsorption capacity was combined with a root system with stable structure to improve the overall performance of the floating bed plant module.

[0016] Furthermore, the material selection and pipe diameter specification determination method of the PVC pipe are as follows:

[0017] Pipes made of different materials were tested for corrosion resistance, strength and biocompatibility. Pipe samples of different materials were placed in a simulated intertidal zone environment in the estuary. Changes in the physical properties of the pipes were regularly tested, and the attachment and growth of organisms on the pipe surface were observed. After a long period of testing and comparison, it was found that PVC material was relatively balanced in terms of corrosion resistance, strength and biocompatibility, and was suitable as a material for pipeline reefs. For the determination of pipe diameter specifications, the body size distribution of estuarine fish and other aquatic organisms was studied, and the cluster analysis method was used to divide the body sizes of organisms into different categories. The number of PVC pipes of different diameters was determined based on the proportion of the number of organisms in each category and the space requirements for activities. For example, for fish with a large number and small size, PVC pipes with diameters of φ5cm and φ10cm are more often selected. For larger fish or organisms that require a larger hiding space, PVC pipes with diameters of φ20cm and φ25cm are appropriately configured to meet the habitat needs of different organisms.

[0018] Furthermore, the weaving structure and mesh size of the wire cage in the gabion box are designed as follows:

[0019] The wire cage adopts a double-twisted hexagonal braided structure, which has high stability and strength. During the braiding process, the twisting angle of the wire is accurately calculated, and the twisting angle α is determined according to the following formula: Where d is the wire diameter, h is the vertical distance between adjacent wires. By adjusting the wire diameter and vertical distance, the twisting angle is optimized to ensure that the wire cage is not easily deformed under the impact of water flow. The mesh size is designed according to the size of the target benthic organisms. A dynamic adaptive mesh size algorithm is used. First, the body size data of common benthic organisms in estuaries are statistically analyzed to obtain the distribution range of the organisms. According to the distribution of organism sizes, the mesh size is divided into multiple levels, and each level corresponds to a certain range of organism sizes. In the initial stage of device installation, a larger mesh size is used to allow small benthic organisms to enter and exit freely. Over time, according to the development of the biological community, the mesh size is gradually adjusted to ensure that the mesh size always adapts to the growth and habitat needs of the organisms.

[0020] Furthermore, the device frame is connected to the anchor in the following manner:

[0021] The frame and anchor are connected by a nylon rope with adjustable length. One end of the nylon rope is fixed at a specific position of the frame by a special buckle structure. The buckle structure can ensure that the nylon rope will not fall off when subjected to tension and is easy to install and disassemble. The other end of the nylon rope is connected to the anchor. The shape and weight of the anchor are designed according to the bottom conditions of the intertidal zone of the estuary. For muddy bottom, a flat anchor is used, which has a larger area and can provide greater mechanical ground force. For sandy bottom, a claw anchor is used, whose claws can penetrate into the sand layer to enhance the anchoring effect. The length of the nylon rope can be adjusted in the range of 3m-5m, and the adjustment mechanism is based on real-time monitoring of tidal water level changes and water flow impact force. After the device is installed, the tidal water level and water flow impact force are monitored by sensors installed on the frame, and the length of the nylon rope is automatically adjusted according to the monitoring data to keep the device stable under different water levels and water flow conditions.

[0022] Furthermore, the buoyancy adjustment method of the foam buoy of the plant floating bed is:

[0023] The foam buoy adopts a partitioned structure inside, which is divided into multiple independent air chambers. Each air chamber is equipped with a valve that can adjust the air pressure. The valve can control the inflow and outflow of the gas in the air chamber, thereby adjusting the buoyancy of the foam buoy. The buoyancy adjustment is based on the balance calculation of the overall weight of the device and the buoyancy of the tide. First, the total weight W of the plant floating bed, pipeline reef, gabion cage and attached organisms is measured. t According to the density of tidal water ρ and the submerged volume V of the device in tidal water i , calculate the required buoyancy F b =ρgV i , where g is the acceleration due to gravity. By adjusting the air pressure in the foam float air chamber, the buoyancy provided by the foam float is equal to or slightly greater than the required buoyancy, ensuring that the plant floating bed can float up and down smoothly with the tide and will not fall off the frame due to excessive buoyancy under extreme weather conditions.

[0024] Furthermore, the fixed angle and height of the PVC pipe in the pipeline reef body on the frame are set as follows:

[0025] The fixing angle of the PVC pipe on the frame is optimized according to the direction of the estuary water flow and the lighting conditions. Through long-term monitoring of the estuary water flow direction, the main flow direction and flow velocity change law of the water flow are obtained, and the PVC pipe is fixed on the frame to make it form a certain angle θ with the water flow direction. The value range of θ is 30°-60°. Such an angle setting can cause turbulence when the water flows through the PVC pipe, increase the oxygen content in the water, and facilitate the entry and exit of organisms into the pipe warehouse. For lighting conditions, the height of the PVC pipe is adjusted according to the changes in sunshine time and solar altitude angle in the estuary area, so that the PVC pipe can obtain suitable light in different seasons and times, promoting the growth of organisms attached to the pipe wall. The height adjustment is achieved by setting a movable fixing device on the frame, and the height of the PVC pipe can be accurately adjusted according to actual needs.

[0026] Furthermore, the surface treatment method of the stones in the gabion box is:

[0027] The surface of the stone is treated with a bio-affinity coating. The coating material is a mixture of natural biological materials and organic adhesives. The natural biological materials include shell powder and coral powder. These materials are rich in calcium and magnesium. The preparation process of the coating includes mixing the natural biological materials and the organic adhesive in a certain proportion, and evenly covering the surface of the stone with the coating by spraying or immersion. The coating thickness is calculated and determined by the following formula: Where T is the coating thickness, m is the mass of the coating per unit area, ρ c is the density of the coating material, S is the surface area of ​​the stone, and the mass of the coating per unit area is determined according to the growth requirements of the attached organisms and the performance of the coating material. The effects of coatings of different thicknesses on the growth of attached organisms are studied experimentally, and the optimal coating thickness is selected to increase the attractiveness of stones to shrimps, crabs and benthic organisms, and promote the habitation and reproduction of organisms in gabions.

[0028] On the other hand, the estuarine fishery habitat restoration survey and assessment method is characterized in that the specific steps of the method are:

[0029] S1. Determination of sampling time: The first survey and assessment will be conducted one month after the restoration device is installed. The time intervals for subsequent assessments will be determined according to the seasonal changes in the estuarine ecosystem and the biological growth cycle. Regular surveys and sampling will be arranged in spring, summer, autumn and winter. Such a sampling schedule can fully reflect the effects of the restoration device on various aquatic organisms in the estuary in different seasons.

[0030] S2, Sampling area division: The area where the restoration device is located is divided into multiple sub-areas, each of which includes a part of the plant floating bed area, the pipeline reef area and the gabion cage area. At the same time, the control sub-areas are divided according to the same area and shape on the nearby tidal flats. The sub-areas are divided using geographic information system technology, and are accurately divided according to the topographic and geomorphic features of the device and the tidal flats to ensure that each sub-area is representative and that the sub-areas in the restoration area and the control area are comparable in environmental conditions;

[0031] S3, sampling method:

[0032] Gabion cage sampling: From the gabion cages in each sub-area, a certain proportion of the cages are selected for sampling according to the random stratified sampling method. For cages with stones of different specifications, samples are collected from the upper, middle and lower layers respectively. Benthic animals and barnacles and oysters attached to the stones are collected into sample bottles. The sampling tools used during the sampling process can penetrate into different positions inside the cages to avoid damage to the organisms and ensure that the collected samples are comprehensive;

[0033] Pipeline reef sampling: In the pipeline reef of each sub-area, several groups of PVC pipes were randomly selected for sampling. For each group of PVC pipes, biological samples were collected from the inlet, middle and outlet respectively. All organisms in the PVC pipes were collected into sample bottles. During sampling, a gentle flushing method was used to flush the organisms out of the pipes, while avoiding flushing away small organisms or damaging biological tissues.

[0034] Plant floating bed sampling: In each sub-area of ​​the plant floating bed, first measure the height, density, and coverage area growth indicators of the ground plants using non-destructive measurement methods, and then select a certain number of modules from the floating bed plant modules according to the equidistant sampling method for destructive sampling, and collect the entire sample into a sorting box. During control sampling, collect 50cm×50cm×50cm sediment samples in the control sub-area, and use the stratified sampling method to collect surface, middle and deep sediments respectively, and collect aquatic biological samples after washing through a 0.5mm sieve;

[0035] S4, sample processing and analysis: all collected samples are brought back to the laboratory. For plant floating bed samples, the above-ground part and the root part are carefully separated, and the dry weight and wet weight are measured using a high-precision balance. At the same time, the chemical composition of plant tissues is analyzed to detect the nutrient content and heavy metal content indicators. For other aquatic biological samples, they are first classified and screened to remove impurities, and then the species are identified by combining morphological identification and molecular biological identification. For the identified organisms, their individual size and weight biological parameters are measured using precision measuring instruments;

[0036] S5, data processing and evaluation index calculation: establish a special database to input and manage the collected and analyzed data, and calculate various evaluation indicators, including biological species richness S, biological quantity N, biological density D b , Biodiversity index Shannon-Wiener index H, biological species richness is obtained by statistically identifying the number of species, the number of organisms is the sum of the number of individuals of each species, and the biological density is calculated based on the area of ​​the sampling area and the number of organisms. Shannon-Wiener index where p i is the proportion of the number of individuals of the ith species to the total number of individuals. By comparing the differences in these indicators between the restoration area and the control area, the restoration effect of the restoration device on the estuarine fishery habitat was evaluated.

[0037] Compared with the existing technology, the three-dimensional device for restoration of estuarine fishery habitat and the survey and evaluation method have the following beneficial effects:

[0038] 1. The invention provides a diverse habitat for different types of aquatic organisms by constructing a three-dimensional restoration device including a plant floating bed area, a pipeline reef area and a gabion cage area. The plant floating bed area can not only purify the water, but also provide a resting place for birds. At the same time, its root system provides an attachment matrix for fish eggs and fry. The pipeline reef area provides a hiding and shelter place for fish and other aquatic organisms. Attached organisms such as oysters and barnacles can grow on the pipe wall. The gabion cage area provides a suitable habitat for shrimps, crabs and various benthic organisms. This three-dimensional habitat restoration device helps to improve the ecological diversity of estuarine fishery habitats, provide better habitat conditions for various aquatic organisms, and thus maintain ecological balance.

[0039] 2. This invention can comprehensively and accurately evaluate the restoration effect of the restoration device on the estuarine fishery habitat by scientifically and reasonably determining the sampling time, dividing the sampling area, sampling methods, and sample processing and analysis steps. By comparing the biological species richness, biological quantity, biological density and biodiversity index indicators in the restoration area and the control area, the effect of the restoration device can be quantitatively evaluated. At the same time, this method can also continuously optimize and improve the restoration device according to the evaluation results to further enhance its ecological restoration effect. This precise evaluation and continuous optimization mechanism will help promote the scientific and standardized process of estuarine fishery habitat restoration work.

[0040] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 Schematic diagram of the three-dimensional device for fishery habitat restoration;

[0043] Figure 2 Schematic diagram of pipeline reef;

[0044] Figure 3 Schematic diagram of gabion box;

[0045] Figure 4 Schematic diagram of plant floating bed;

[0046] Figure 5 Operational diagram of the survey and assessment method flow for estuarine fishery habitat restoration;

[0047] In the figure: 1. Plant floating bed; 2. Pipe reef; 201. Stainless steel frame; 202. PVC pipe; 203. First nylon rope; 204. Holes on PVC pipe; 3. Gabion box; 301. Stainless steel frame; 302. Wire cage; 303. Stone; 4. Anchor; 5. Stainless steel frame structure; 6. Second nylon rope; 7. Plant floating bed; 701. Foam buoy; 702. Angle iron; 703. Screw holes on the angle iron for fixing the floating bed; 704. Plant roots; 705. Polyethylene mesh. DETAILED DESCRIPTION

[0048] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0049] Embodiment 1

[0050] This embodiment describes that in a small estuary area, fishery resources are gradually reduced due to water pollution and habitat destruction. The intertidal zone of the estuary has a slow flow, the bottom is mainly muddy, and there are certain human activities in the surrounding area, such as small industrial emissions and agricultural non-point source pollution.

[0051] According to the estuary water quality and biological needs, reed and calamus plant roots were selected to form floating bed plant modules. The average volume of a single plant root and the number of plant roots in the module were measured, and the total volume of the plant roots was calculated. The total volume was then obtained based on the module size, and the plant root filling ratio was determined to be 60% according to the formula: Where P is the filling ratio of plant roots, Vr is the total volume of plant roots, V m The foam float adopts a partitioned structure to adjust the air pressure in the air chamber to balance the buoyancy and the weight of the device, ensuring that the floating bed floats smoothly with the tide.

[0052] After material testing, PVC pipes were selected as the pipeline reef material. After studying the body size distribution of estuarine fish, it was determined to use three types of PVC pipes with diameters of 10cm, 15cm, and 20cm, with 6, 5, and 4 pipes respectively. At a height of 0.5m, the PVC pipes were fixed on the frame at a 45° angle to the water flow direction, so that they can generate turbulence to increase oxygen and facilitate the entry and exit of organisms. The number of holes on a single PVC pipe is set according to the pipe diameter specifications and ecological function requirements, and the hole distribution density is reasonably distributed after calculation.

[0053] The gabion cage adopts a double-twisted hexagonal woven structure of wire cages. The wire diameter is 3mm, the vertical distance between adjacent wires is 5mm, and the twisting angle is determined by the formula α=arctan(3 / 5). The mesh size is initially set to 5cm×5cm, which is adjusted according to the development of the biological community. Each cage is filled with three specifications of stones, namely 5cm-10cm, 10cm-15cm, and 15cm-20cm. Each specification is filled with 4 cages, a total of 16 cages. After calculating the filling ratio of stones of different specifications, the formula is: Where R i is the filling ratio of the i-th specification stone, N i is the number of stones of the i-th specification, N t is the total number of stones in the gabion box, which are placed in the lower square of the frame using a layered random filling algorithm.

[0054] The bottom of the stainless steel frame is welded with steel plates, and steel pipes are welded at heights of 0.25m and 0.75m with 50cm intervals horizontally and vertically to form 16 small squares. The staggered welding method is used to improve the impact resistance. The frame is connected to the flat anchor with nylon ropes around it. The length of the nylon rope is monitored in real time according to the changes in tidal water levels and the impact force of the water flow, and can be adjusted within the range of 3m-5m.

[0055] One month after the restoration device is installed, the first survey and evaluation is conducted when the water temperature rises in the spring. Subsequent sampling is carried out at specific periods of the season, including the summer when biological growth is vigorous, after the biological reproduction period in the autumn, and before the organisms enter the dormant period in the winter.

[0056] The area where the restoration device is located is divided into four sub-areas using geographic information system technology. Each sub-area includes a plant floating bed area, a pipeline reef area and a part of the gabion box area. At the same time, control sub-areas of the same area and shape are divided on the nearby mudflats.

[0057] 30% of the gabions in each sub-area were randomly selected in layers, and samples were collected from the upper, middle and lower layers of the gabions with different specifications. Benthic animals and attached organisms were collected using special sampling tools.

[0058] Three groups of PVC pipes were randomly selected from the pipeline reef in each sub-area, and biological samples were collected from the inlet, middle and outlet, and the organisms in the pipes were gently flushed.

[0059] The height, density, and coverage area growth indicators of the plants on the floating bed were measured, and 10 floating bed plant modules were equidistantly selected for destructive sampling, and the samples were collected and put into a sorting box. A 50cm×50cm×50cm sediment sample was collected from the control area, and after stratified sampling, the aquatic biological samples were collected by washing through a 0.5mm sieve.

[0060] The samples are brought back to the laboratory, and the above-ground and root parts of the plant floating bed samples are separated to measure the dry weight, wet weight and analyze the chemical composition. After other aquatic biological samples are classified and screened and impurities removed, morphology and molecular biology are used to identify the species, and precision instruments are used to measure individual size, weight and biological parameters.

[0061] Establish a database to input data, calculate the species richness, quantity, density, and Shannon-Wiener index evaluation indicators, where p i It is the ratio of the number of individuals of the i-th species to the total number of individuals. The restoration effect is evaluated by comparing the differences between the restoration area and the control area.

[0062] Embodiment 2

[0063] This embodiment describes that due to the construction of various water conservancy projects such as beach reclamation in a certain estuary area, the intertidal zone aquatic habitat is severely lost, the number of fish and benthic organisms is greatly reduced, and the water ecosystem is unbalanced.

[0064] Reeds with well-developed root systems are selected to fill the floating bed plant modules. The floating bed plant modules are placed in the upper square of the stainless steel frame and fixed with angle irons, screws and nylon ropes. Foam floats are used around to adjust the buoyancy to ensure that they float smoothly with the tide.

[0065] After material testing, PVC pipes were selected. The pipe diameter specifications were determined based on the size distribution of fish in the estuary (mostly small and medium-sized fish). The PVC pipes were fixed to the upper grid of the frame at a specific angle (45° to the direction of the water flow) and height (adjusted according to the sunlight). The hole distribution density was calculated and set according to the ecological function requirements. The formula is: Where D is the hole distribution density, n is the number of holes on a single PVC pipe, r is the radius of the PVC pipe, and L is the length of the PVC pipe, providing a good environment for fish and attached organisms.

[0066] The wire cage adopts a double-twisted hexagonal woven structure. The mesh size is initially large and is subsequently adjusted according to the growth of benthic organisms. After the stones are treated with bioaffinity coating, they are filled with stones of different specifications according to the layered random filling algorithm. The formula is: Where R i is the filling ratio of the i-th specification stone, N i is the number of stones of the i-th specification, N t It is the total number of stones in the gabion cages, which are placed in the bottom square of the frame to provide a habitat for shrimps, crabs and benthic organisms.

[0067] The stainless steel frame adopts a staggered welding process, with steel pipes welded at intervals horizontally and vertically to form a grid, a steel plate base welded at the bottom, and adjustable nylon ropes connected to flat anchors suitable for the bottom (mud) around it. The length of the nylon rope is adjusted according to the tidal water level and water flow impact force monitoring data to fix the device in the intertidal zone of the estuary.

[0068] One month after the device was installed, the sampling time was determined according to seasonal characteristics, and the restoration device and nearby tidal flats were divided into multiple sub-areas using a geographic information system to ensure comparability between the restoration area and the control area.

[0069] Samples from plant floating beds, pipeline reefs, gabion cages and control areas were collected according to their respective sampling methods and brought back to the laboratory for processing and analysis, including plant weight, component analysis, biological classification, identification and parameter measurement.

[0070] After data processing and calculation of evaluation indicators, the richness, quantity, density and diversity index of biological species in the restoration area were significantly higher than those in the control area, and the number of fish and benthic organisms gradually increased, indicating that the device can provide suitable habitats for various swimming animals and benthic animals in the estuary, and has a significant effect on the restoration of estuarine fishery habitats.

[0071] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modifications to the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any brief modifications, changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still belong to the technical solution of the present invention.

Claims

1. A three-dimensional device for restoring estuary fishery habitat, characterized in that: The device comprises a plant floating bed area (7), a pipeline reef area (2), a gabion box area (3) and a stainless steel frame structure (5); The plant floating bed area (7) comprises: a foam float (701), an angle iron (702), screw holes (703) on the angle iron for fixing the floating bed, a plant root system (704), and a polyethylene mesh (705); The pipeline reef area (2) comprises: a stainless steel frame (201), a PVC pipe (202), a first nylon rope (203), and a hole (204) opened on the PVC pipe; The gabion box area (3) comprises: a stainless steel frame (301), a wire cage (302), and stones (303); Plant floating bed area (7): located at the upper part of the stainless steel frame (201), it is composed of foam floats (701), stainless steel pipe frame and floating bed plant modules. The upper part of the stainless steel frame (201) is welded into 9 squares by angle irons (703), and each square is placed with a floating bed plant module. The module and the frame are fixed with screws through the holes on the angle irons (703). The floating bed plant module is composed of upper and lower layers of polyethylene mesh (706) and plant roots (705) filled in the middle, which are clamped and fastened by plastic tie bands. The entire floating bed frame is nested in the stainless steel frame (201), located at the uppermost part of the frame, and connected to the frame by nylon ropes (203). The foam floats (701) around it enable the floating bed to float up and down with the tide without leaving the frame. Plant growth can purify the water body. The surface of the floating bed provides a resting place for birds, and the root system provides an attachment matrix for fish eggs and fry. The filling ratio of the plant root system (705) in the floating bed plant module is determined by the following formula: Where P is the filling ratio of plant roots (705), V r is the total volume of the plant root system (705), V m is the total volume of the floating bed plant module, the total volume of the plant root system (705) is obtained by measuring the product of the average volume of a single plant root system (705) and the number of plant roots (705) in the module, and the total volume of the floating bed plant module is calculated according to the size of the module; Pipeline reef area (2): located in the middle of the stainless steel frame (201) device and above the gabion cage, 5 PVC pipes (202) of different diameters are placed in 16 squares on the upper part of the frame, one group in each square, fixed to the frame with nylon rope (203). This area can provide a hiding place and shelter for fish and aquatic organisms, and attached organisms can grow on the pipe wall. The density of hole distribution on the PVC pipe (202) is calculated according to the following formula: Wherein D is the hole distribution density, n is the number of holes on a single PVC pipe (202), r is the radius of the PVC pipe (202), L is the length of the PVC pipe (202), and the number of holes on a single PVC pipe (202) is set according to the ecological function requirements of PVC pipes (202) of different pipe diameters; Gabion box area (3): A gabion box area (3) is set at the bottom of the stainless steel frame (201) device, and an independent cage net is made of a wire cage (302). Each cage net is filled with stones (303) of different specifications. Four cage nets are filled with each specification, totaling 16 cage nets, which are randomly placed in 16 small squares at the bottom of the frame device. Removable cross bars are provided around the frame. The cage provides a suitable habitat for shrimps, crabs and various benthic organisms. The filling layout of stones (302) of different specifications in the gabion box adopts a hierarchical random filling algorithm. The specific steps are as follows: first, the gabion box is divided into a number of small units of equal volume. For each size of stone (302), a small unit is randomly selected for filling. The filling ratio of stones (302) of different specifications in the gabion box is calculated according to the following formula: Where R i is the filling ratio of the i-th specification stone (302), N i is the number of stones (302) of the i-th specification, N t is the total number of stones (302) in the gabion cage, the number of stones (302) is determined according to the cage volume, the size of the stones (302) and the habitat requirements of the organisms; Stainless steel frame structure (5): A stainless steel welded frame is used as a fixing device, and a steel plate is welded at the bottom as a base to prevent it from sinking into sediments. Steel pipes are welded horizontally and vertically at 50 cm intervals at heights of 0.25 m and 0.75 m to form 16 small squares of 50 cm × 50 cm. The entire frame is connected to anchors (4) with nylon ropes (203) around it to fix the device in the intertidal zone of the estuary to prevent it from being knocked down by typhoon extreme weather. The welding process of the frame adopts a staggered welding method. First, the horizontal steel pipe and the vertical steel pipe are spot welded and fixed at each intersection. Then, starting from one corner of the frame, continuous welding is performed in a specific order. After each welding distance, an intersection is skipped and welding is continued. The determination of this welding order is obtained by analyzing the force of the frame under the impact of water flow and wind and waves. It has been verified through simulation experiments that it can effectively improve the impact resistance of the frame.

2. The three-dimensional device for restoring estuary fishery habitat according to claim 1, characterized in that: The selection of the plant root system (705) in the floating bed plant module is based on the water quality conditions of the intertidal zone of the estuary and the requirements for biological attachment, specifically: The ecological function of common aquatic plant root systems (705) in the intertidal zone of the estuary is analyzed, including the ability to absorb nitrogen and phosphorus nutrients in the water body and the stability of attachment provided for fish eggs and larvae. An ecological function evaluation model of plant root systems (705) is established. The evaluation indicators include root surface area, root hair density, and secretion composition. Through field sampling and laboratory analysis of various plant root systems (705), data of various evaluation indicators are obtained. The hierarchical analysis method is used to determine the weight of each evaluation indicator. The comprehensive ecological function value of each plant root system (705) is calculated according to the evaluation model, and plant root systems (705) with higher comprehensive ecological function values ​​are selected for use in floating bed plant modules. The combination method is matched according to the characteristics of different plant root systems (705).

3. The three-dimensional device for restoring estuary fishery habitat according to claim 1, characterized in that: The material selection and pipe diameter specification determination method of the PVC pipe (202) are as follows: The corrosion resistance, strength and biocompatibility of pipes made of different materials were tested. Pipe samples of different materials were placed in a simulated intertidal zone environment in an estuary. The physical property changes of the pipes were regularly tested. At the same time, the attachment and growth of organisms on the pipe surface were observed. After a long period of testing and comparison, it was found that PVC material showed a relatively balanced performance in terms of corrosion resistance, strength and biocompatibility, and was suitable as a material for pipe reefs. For the determination of pipe diameter specifications, the body size distribution of estuarine fish and other aquatic organisms was studied, and the cluster analysis method was used to classify the body sizes of organisms into different categories. According to the number ratio of each category of organisms and the activity space requirements, the number of PVC pipes (202) of different pipe diameter specifications was determined.

4. The three-dimensional device for restoring estuary fishery habitat according to claim 1, characterized in that: The weaving structure and mesh size of the wire cage (302) in the gabion box are designed as follows: The lead wire cage (302) adopts a double-twisted hexagonal braided structure, which has high stability and strength. During the braiding process, the twisting angle of the lead wire is accurately calculated, and the twisting angle α is determined according to the following formula: Where d is the wire diameter, h is the vertical distance between adjacent wires. The twisting angle is optimized by adjusting the wire diameter and the vertical distance. The mesh size is designed according to the size of the target benthic organisms. A dynamic adaptive mesh size algorithm is used. First, a statistical analysis is performed on the size data of common benthic organisms in estuaries to obtain the distribution range of the organisms. According to the distribution of organism sizes, the mesh size is divided into multiple levels, and each level corresponds to a certain range of organism sizes. In the initial stage of device installation, a larger mesh size is used. According to the development of the biological community, the mesh size is gradually adjusted to ensure that the mesh size always adapts to the growth and habitat needs of the organisms.

5. The three-dimensional device for restoring estuary fishery habitat according to claim 1, characterized in that: The device frame is connected to the anchor (4) in the following manner: A nylon rope (203) with adjustable length is used to connect the frame and the anchor (4). One end of the nylon rope (203) is fixed to a specific position of the frame through a special buckle structure. The buckle structure can ensure that the nylon rope (203) will not fall off when subjected to tension and is easy to install and disassemble. The other end of the nylon rope (203) is connected to the anchor (4). The shape and weight of the anchor (4) are designed according to the bottom conditions of the intertidal zone of the estuary. For muddy bottom, a flat anchor (4) is used, which has a larger area and can provide greater mechanical ground force. For sandy bottom, a claw anchor (4) is used, whose claw can penetrate into the sand layer to enhance the anchor (4) fixing effect. The length of the nylon rope (203) can be adjusted within a range of 3m-5m. The adjustment mechanism is based on real-time monitoring of tidal water level changes and water flow impact force. After the device is installed, the tidal water level and water flow impact force are monitored by a sensor installed on the frame, and the length of the nylon rope (203) is automatically adjusted according to the monitoring data, so that the device remains stable under different water level and water flow conditions.

6. The three-dimensional device for restoring estuary fishery habitat according to claim 1, characterized in that: The buoyancy adjustment method of the foam float (701) of the plant floating bed is as follows: The foam buoy (701) has a partitioned structure inside, which is divided into multiple independent air chambers. Each air chamber is equipped with a valve that can adjust the air pressure. The valve can control the inflow and outflow of the gas in the air chamber, thereby adjusting the buoyancy of the foam buoy (701). The buoyancy adjustment is based on the balance calculation of the overall weight of the device and the buoyancy of the tide. First, the total weight W of the plant floating bed, pipeline reef, gabion cage and attached organisms is measured. t According to the density of tidal water ρ and the submerged volume V of the device in tidal water i , calculate the required buoyancy F b =ρgV i , where g is the acceleration due to gravity. By adjusting the air pressure in the air chamber of the foam float (701), the buoyancy provided by the foam float (701) is equal to or slightly greater than the required buoyancy, ensuring that the plant floating bed can float up and down smoothly with the tide and will not fall off the frame due to excessive buoyancy under extreme weather conditions.

7. The three-dimensional device for restoring estuary fishery habitat according to claim 1, characterized in that: The fixed angle and height of the PVC pipe (202) in the pipeline reef body on the frame are set as follows: The fixing angle of the PVC pipe (202) on the frame is optimized according to the direction of the estuary water flow and the lighting conditions. By long-term monitoring of the estuary water flow direction, the main flow direction and flow velocity change law of the water flow are obtained, and the PVC pipe (202) is fixed on the frame so that it forms a certain angle θ with the water flow direction. The value range of θ is 30°-60°. Such an angle setting can cause turbulence when the water flows through the PVC pipe (202), increase the oxygen content in the water, and facilitate the entry and exit of organisms into the pipe warehouse. With regard to the lighting conditions, the height of the PVC pipe (202) is adjusted according to the sunshine time and the change of the solar altitude angle in the estuary area, so that the PVC pipe (202) can obtain suitable light in different seasons and times, thereby promoting the growth of organisms attached to the pipe wall. The height adjustment is achieved by arranging a movable fixing device on the frame, and the height of the PVC pipe (202) can be accurately adjusted according to actual needs.

8. The three-dimensional device for restoring estuary fishery habitat according to claim 1, characterized in that: The surface treatment method of the stones (302) in the gabion box is: The surface of the stone (302) is treated with a bio-affinity coating, wherein the coating material is a mixture of natural biological materials and organic adhesives, wherein the natural biological materials include shell powder and coral powder, and these materials are rich in calcium and magnesium. The preparation process of the coating includes uniformly mixing the natural biological materials and the organic adhesive in a certain proportion, and uniformly covering the surface of the stone (302) with the coating by spraying or immersing. The thickness of the coating is determined by the following formula: Where T is the coating thickness, m is the mass of the coating per unit area, ρ c is the density of the coating material, and S is the surface area of ​​the stone (302).

9. A survey and assessment method for restoration of estuarine fishery habitats, characterized in that: The specific steps of this method are: S1. Determination of sampling time: The first survey and assessment will be conducted one month after the restoration device is installed. The time intervals for subsequent assessments will be determined according to the seasonal changes in the estuarine ecosystem and the biological growth cycle. Surveys and sampling will be arranged in spring, summer, autumn and winter respectively. Such a sampling schedule can fully reflect the effects of the restoration device on various aquatic organisms in the estuary in different seasons. S2, Sampling area division: The area where the restoration device is located is divided into multiple sub-areas, each of which includes a plant floating bed area (7), a pipeline reef area (2) and a part of the gabion box area (3). At the same time, a control sub-area with the same area and shape is divided on the nearby tidal flats. The sub-areas are divided using geographic information system technology, and are accurately divided according to the topographic and geomorphic features of the device and the tidal flats to ensure that each sub-area is representative and that the sub-areas in the restoration area and the control area are comparable in terms of environmental conditions; S3, sampling method: Sampling of gabions: From the gabions in each sub-area, a certain proportion of the gabions are selected for sampling according to the random stratified sampling method. For the gabions with stones (302) of different specifications, samples are collected from the upper, middle and lower layers respectively. Benthic animals and barnacles and oysters attached to the stones (302) are collected into sample bottles. During the sampling process, sampling tools are used to penetrate into different positions inside the gabions to avoid damage to the organisms and ensure that the collected samples are comprehensive. Pipeline reef sampling: In the pipeline reef of each sub-area, several groups of PVC pipes (202) are randomly selected for sampling. For each group of PVC pipes (202), biological samples are collected from the inlet, middle and outlet respectively. The organisms in all PVC pipes (202) are collected into a sample bottle. During sampling, a gentle flushing method is used to flush the organisms out of the pipe, while avoiding flushing away small organisms or damaging biological tissues; Plant floating bed sampling: In each sub-area of ​​the plant floating bed, first measure the height, density, and coverage area growth indicators of the ground plants using non-destructive measurement methods, and then select a certain number of modules from the floating bed plant modules according to the equidistant sampling method for destructive sampling, and collect the entire sample into a sorting box. During control sampling, collect 50cm×50cm×50cm sediment samples in the control sub-area, and use the stratified sampling method to collect surface, middle and deep sediments respectively, and collect aquatic biological samples after washing through a 0.5mm sieve; S4, sample processing and analysis: all collected samples are brought back to the laboratory. For plant floating bed samples, the above-ground part and the root part are carefully separated, and the dry weight and wet weight are measured using a high-precision balance. At the same time, the chemical composition of plant tissues is analyzed to detect the nutrient content and heavy metal content indicators. For other aquatic biological samples, they are first classified and screened to remove impurities, and then the species are identified by combining morphological identification and molecular biological identification. For the identified organisms, their individual size and weight biological parameters are measured using precision measuring instruments; S5, data processing and evaluation index calculation: establish a special database to input and manage the collected and analyzed data, and calculate various evaluation indicators, including biological species richness S, biological quantity N, biological density D b , Biodiversity index Shannon-Wiener index H, biological species richness is obtained by statistically identifying the number of species, the number of organisms is the sum of the number of individuals of each species, and the biological density is calculated based on the area of ​​the sampling area and the number of organisms. Shannon-Wiener index where p i is the proportion of the number of individuals of the ith species to the total number of individuals. By comparing the differences in these indicators between the restoration area and the control area, the restoration effect of the restoration device on the estuarine fishery habitat was evaluated.

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