A method for natural collection of sea urchin seedlings in marine areas

Abstract

This invention relates to a method for natural sea urchin seed collection in marine areas. The method selects areas with abundant sea urchin resources as seed collection points based on statistical data collected throughout the year. Then, using the nearshore seed collection point as the center and the line connecting it to two other seed collection points on its outer perimeter as the radius, seed collection platforms are erected parallel to each other within a "fan-shaped" radius to construct a "fan-shaped" seed collection area. The development of mature sea urchin gonads and the number of planktonic larvae at the seed collection points are monitored regularly to accurately determine the seed collection time. Finally, a new type of seed collection net cage is deployed as the seed collection device according to the planned seed collection volume for seed collection. Compared with traditional net bag natural seed collection, this invention increases efficiency by 20-30%, reduces labor demand by 30%, facilitates mechanized operation, meets the requirements of large-scale natural seed collection industry development, and provides support for subsequent industrial restructuring and sustainable development, thus having significant implications for the sustainable development of the marine industry.

Description

Technical Field

[0001] This invention belongs to the field of marine aquaculture technology, specifically relating to a method for natural seed collection from sea urchin areas. Background Technology

[0002] Sea urchins are an important part of seafood delicacies. In my country, the main types of sea urchins farmed include the Ezo-Mafum sea urchin, the Spurious Sea urchin (Dalian Purple Sea Urchin), and the Yellow Sea urchin. The Ezo-Mafum sea urchin, a new species introduced from Japan, is popular with consumers both domestically and internationally due to its rapid growth and high gonadal fullness at maturity. The Dalian Purple Sea urchin, a native species of Dalian, is popular in the domestic market due to its large size, rich nutrition, high market acceptance, and large consumer base. The Yellow Sea urchin, also a native species of the Yellow and Bohai Seas, is large in size, has a high gonadal meat yield, and is relatively cheaper; it can be processed into a fresh product.

[0003] In recent years, with the improvement of people's living standards, the demand for aquatic products such as sea urchins has continued to increase. According to statistics from the China Fisheries Yearbook 2014, the aquaculture output in 2013 was 6,427 tons, an increase of 9.83% compared to 5,852 tons in 2012. The increase in the output of Ezo-mafuku sea urchins accounted for the majority of this growth. However, in 2013, the sea urchin aquaculture output in Liaoning Province was only 142 tons, significantly lower than that in Shandong (4,120 tons) and Guangdong (2,160 tons). The lack of seedlings is a key factor restricting the rapid development of the sea urchin aquaculture industry.

[0004] Natural sea urchin seed collection is not only low-cost, simple to operate, economically efficient, and easy to promote and apply, but also ensures that the surviving individuals have strong resilience due to natural selection in the sea area, making it an important means of cultivating high-quality seedlings. In recent years, however, the number of seedlings has declined due to factors such as increased costs of indoor artificial seedling cultivation, water quality issues, and difficulties in the seedling preservation process, failing to meet production demands. Therefore, there is an urgent need for a stable and efficient method and device for natural sea urchin seed collection.

[0005] This invention, drawing on practical production experience and through innovative research and development and repeated experimental testing, proposes a highly efficient method for natural sea urchin seed collection. Based on the biological characteristics and gonadal development of sea urchins, a novel seed collection device is deployed at specific locations and times to complete seed collection. This invention replaces the long larval rearing time and insufficient benthic diatoms and other food sources during the larval metamorphosis stage in indoor seed breeding. It also improves upon traditional seed collection methods that require extensive manual labor for stringing corrugated boards, which sway dramatically with ocean currents, affecting seed attachment; and the time-consuming and labor-intensive process of tying and untying net-hanging seed collection, resulting in low efficiency due to entirely manual seed retrieval. The widespread use of this invention will significantly improve labor productivity, reduce operational intensity, improve seed quality, and promote the healthy and sustainable development of the industry. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a method for natural sea urchin seed collection in sea areas, so as to solve the problems of unstable seed collection, high labor intensity and low efficiency in existing sea urchin sea area collection methods.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for naturally collecting sea urchin seedlings in marine areas, the steps of which are as follows:

[0009] (1) Selection of seedling collection sites

[0010] Based on the sea urchin biomass counted during the annual harvesting process, areas with abundant sea urchin biomass were selected as seed collection sites. Areas with abundant sea urchin biomass refer to sea areas with rich algae resources and sea urchin biomass reaching or exceeding 0.15 kg / m².

[0011] (2) Construct a "fan-shaped" seedling collection area

[0012] Using the nearshore seed collection point as the center and the line connecting the nearshore seed collection point to the other two seed collection points in the outer direction as the radius, seed collection platforms are erected in parallel between the "fan-shaped" radii to construct a "fan-shaped" seed collection field. The "fan-shaped" seed collection field is mainly due to the fact that during the breeding season, the sea urchin larvae will shift their position with the ocean currents, forming a fan-shaped spread.

[0013] Preferably, the spacing between the parallel erected platforms is 3m to 5m.

[0014] (3) Regular monitoring of seedling collection sites

[0015] The development of gonads and the number of planktonic larvae in mature sea urchins at the seed collection site are monitored regularly. When the average gonad index of the parent sea urchins reaches 20%~25% or the density of tetracocciae reaches 2~5 per m³, seed collection devices are deployed on the rafts in the "fan-shaped" seed collection area. The average gonad index is calculated as gonad weight / body weight * 100%.

[0016] Preferably, the method for monitoring the number of planktonic larvae is as follows: during the sea urchin breeding season, 1 m³ of water sample is taken weekly from the seed collection point using a planktonic net from a water layer 3 m to 5 m below the surface, and the density of tetracocciae in the water sample is observed.

[0017] (4) Deployment of seedling collection device

[0018] The seedling collection device uses seedling collection net cages. Several seedling collection net cages are fixed on the seedling collection platform raft in the "fan-shaped" seedling collection field. The seedling collection net cages are suspended in water at a depth of 3m to 5m underwater.

[0019] Preferably, the seedling collection device in the "fan-shaped" seedling collection area is arranged according to the planned seedling collection volume:

[0020] S=d*n*r*1000

[0021] Where: S represents the total number of seedlings collected, in units of seedlings; d represents the density of tetracocciae, in units of seedlings / m³. 3 ; n represents the average number of net cages on a single seedling collection raft, in units of individual cages; r represents the total number of seedling collection rafts, in units of collection rafts.

[0022] Preferably, the distance between adjacent seedling collection cages on the seedling collection platform is not less than 0.3m.

[0023] (5) Seedling collection and recovery of seedling collection equipment

[0024] After the sea urchin seedlings in the collection net cages have been set up for 40 to 60 days and have grown to 2 to 3 mm in size, the collection net cages are retrieved. The sea urchin seedlings attached to the collection net cages are then rinsed and retrieved to complete the seedling collection work.

[0025] Preferably, the seedling collection cage includes a polyethylene mesh cover, an internal support, and a seedling collection mesh core.

[0026] The netting is a cylindrical net, with sealing ropes at the top and bottom openings. The sealing ropes allow the seedling collection netting cage to be opened or closed, and to be connected to the top hanging rope and the bottom weight.

[0027] The internal support includes annular supports spaced apart inside the cylindrical netting, and a longitudinal support penetrating through the center of the annular supports. The two ends of the longitudinal support are fixed by closed binding ropes at the top and bottom of the cylindrical netting, respectively, to keep the longitudinal support in the center of the seedling collection netting. The longitudinal support and the annular supports are used to support and fix the cylindrical netting.

[0028] The seed collection net core consists of several polyethylene net sheets, which are movably connected to a longitudinal support. The several polyethylene net sheets are arranged alternately and staggered in a spiral shape on the longitudinal support for the attachment and collection of sea urchin seedlings.

[0029] More preferably, the internal support is a hollow cylindrical tube made of polyethylene or polyvinyl chloride to reduce the weight of the seedling collection net cage.

[0030] More preferably, the surface of the hollow longitudinal support structure is provided with spirally spaced locking holes, and a T-shaped buckle is provided at the connection end between the seedling collection net core and the longitudinal support. The T-shaped buckle engages with the locking holes on the surface of the longitudinal support. The seedling collection net core E4 is snapped onto the longitudinal support E2 with room for movement, preventing excessive impact from the ocean current from causing the connecting end of the triangular polyethylene net to break. At the same time, the spirally spaced arrangement increases the seedling attachment area, improves the seedling collection effect, and avoids seedling detachment during the collection process due to friction between the seedling collection net cores.

[0031] Preferably, the seedling collection net core is a plurality of triangular or fan-shaped polyethylene net sheets.

[0032] Preferably, the seedling collection device can also be used to collect scallop and conch seedlings.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. By establishing a periodic monitoring mechanism for sea urchin resource advantage areas as seed collection sites, we can systematically understand the developmental stages and densities of natural larvae in different regions and at different times, providing a basis for determining accurate seed collection areas and collection times.

[0035] 2. By combining the seed collection demand with the diffusion principle of planktonic larvae in natural marine areas, a "fan-shaped" seed collection site model is constructed to accurately determine the seed collection area and precisely configure the seed collection equipment, saving manpower and material resources and facilitating standardized seed collection production;

[0036] 3. The new seedling collection net cage has a large space and a high attachment surface area. The spiral fan-shaped polyethylene net design saves on the amount of seedling attachment substrate and leaves enough space between the net sheets to prevent seedlings from falling off during the collection process due to friction between the seedling cores. It is also easy to clean by machinery. It replaces the original seedling collection net bags and corrugated plate attachment substrates. It not only reduces the multiple processes of filling, tying, and hanging the seedling collection net bags, which greatly reduces the complexity of seedling collection and the intensity of labor, but also greatly improves seedling collection efficiency, seedling collection water utilization rate, and seedling rinsing operation.

[0037] 4. The seedling collection net core of the seedling collection net cage can be processed into standardized parts, which facilitates processing, manufacturing, disassembly and installation, freeing up labor and significantly reducing production costs;

[0038] Compared to traditional net bag-based natural seed collection, this invention improves efficiency by 20-30% and reduces labor requirements by 30%. It significantly enhances the precision of seed collection operations, increases the utilization efficiency of the seed collector, reduces the labor intensity of workers during the collection and separation process, facilitates mechanized operations, and meets the requirements of large-scale natural seed collection industry development, thus contributing to subsequent industrial restructuring and sustainable development. Naturally obtained seedlings, due to their high survival rate and strong resilience, can better drive regional economic development and are of great significance to the sustainable development of the marine industry when widely used. Attached Figure Description

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0040] Figure 1 This is a flowchart of the natural sea urchin seed collection method in Embodiment 1 of the present invention;

[0041] Figure 2This is a schematic diagram illustrating the construction principle of the "fan-shaped" sea urchin seed collection site in the natural sea area of ​​Embodiment 1 of the present invention.

[0042] Figure 3 This is a schematic diagram of the seed collection status of the seed collection net cages on a single seed collection platform raft in the natural seed collection "fan-shaped" seed collection field in the sea urchin sea area in Embodiment 1 of the present invention.

[0043] Figure 4 for Figure 3 A schematic diagram of the structure of the seedling net cage;

[0044] Figure 5 for Figure 4 A schematic diagram of the structure of the seedling net core installed on the longitudinal support;

[0045] Figure 6 for Figure 5 Top view in the middle;

[0046] In the diagram: A. Near-shore seedling collection point; B. First outer seedling collection point; C. Second outer seedling collection point; D. Raft; E. Seedling collection net cage; E1. Net cover; E2. Longitudinal support; E3. Circular support; E4. Seedling collection net core; E5. Enclosed binding rope; E6. T-shaped buckle; E7. Clip hole; F. Falling stone. Detailed Implementation

[0047] The present invention will be further explained below with reference to specific implementation schemes, but the technical solution of the present invention is not limited to this embodiment.

[0048] Example 1

[0049] Taking the applicant's 2020 sea urchin natural seed collection experiment as an example, this paper details the methods for natural seed collection in sea urchin areas, such as... Figure 1 As shown, the steps are as follows:

[0050] (1) Selection of seedling collection sites

[0051] Based on nearshore diving and harvesting data and nearshore site biological resource survey data from 2016 to 2020, it was determined that the western area of ​​Xiaohao Island is rich in algae resources and the sea urchin biological resource can reach 0.5 kg / m², making it an advantageous area for purple sea urchin resources. This sea area was selected as the seed collection site.

[0052] (2) Construct a "fan-shaped" seedling collection area

[0053] like Figure 2As shown, within the advantageous area of ​​purple sea urchin resources, with the nearshore seed collection point A as the center and the line connecting the nearshore seed collection point to the first outer seed collection point B and the second outer seed collection point C in its outer direction as the radius, three seed collection rafts D are erected in parallel between the radii, with a spacing of 4m between the seed collection rafts D, forming a "fan-shaped" seed collection field. The "fan-shaped" seed collection field is mainly due to the fact that during the breeding season, the sea urchin larvae will shift their position with the ocean currents, forming a fan-shaped spread.

[0054] (3) Regular monitoring of seedling collection sites

[0055] From early June 2020, the gonadal development of mature purple sea urchins (i.e., parent sea urchins) at the seed collection sites was monitored, and the average gonadal index was monitored. The average gonadal index = gonadal weight / body weight * 100%. Initially, the average gonadal index was about 8%. Surveys were conducted once a week, with 30 purple sea urchins sampled each time, and the average gonadal index was calculated. On July 20, 2020, the average gonadal index reached a peak of 30.26%. On July 25, the average gonadal index dropped to 25.35%, and continued to decline until August 20, when the gonadal index was 18.13%. Therefore, it was determined that the time of sperm and egg release in the sea urchin area was late July.

[0056] Starting in early June, the population of sea urchin planktonic larvae was monitored. Weekly water samples of 1 m³ were collected from a depth of 3-5 m using a planktonic net to observe the density of tetraarmed larvae in the samples. Based on the sea urchin planktonic larvae monitoring survey at the seed collection site at the end of July, tetraarmed larvae were found, with a density of 4.5 larvae / m³. Seed collection equipment was then deployed in preparation for seed collection.

[0057] (4) Deployment of seedling collection device

[0058] From July 20th to 30th, the seed collection equipment will be deployed. This year's plan is to collect 1 million sea urchin seedlings. The deployment of the seed collection equipment will be based on the planned collection volume.

[0059] S=d*n*r*1000

[0060] Where: S represents the total number of seedlings collected, in units of seedlings; d represents the density of tetracocciae, in units of seedlings / m³. 3 ; n represents the average number of seedling collection net cages on a single seedling collection raft, in units of individual; r represents the number of seedling collection rafts, in units of rafts. According to the density of tetracocciae larvae monitored in step (3), the density is 4.5 individuals / m³, i.e., d is 4.5; the “fan-shaped” seedling collection area has a total of 3 seedling collection rafts, i.e., r is 3; a total of 240 seedling collection net cages are fixed on the 3 seedling collection rafts, and the distance between adjacent seedling collection net cages on the seedling collection rafts is 0.3m to 0.4m, so the average number of seedling collection net cages on a single seedling collection raft, n, is 80; the estimated seedling collection volume S according to the formula is 1.08 million.

[0061] like Figure 3As shown, several seedling collection net cages E are fixedly hung on the platform raft D. The distance between adjacent seedling collection net cages E on the platform raft D is 0.3m~0.4m. The seedling collection net cages E are hung at a water level of 3.5m underwater. The platform raft D is erected in parallel with a distance of 3m~5m between them.

[0062] like Figure 4 As shown, the seedling collection cage E includes a polyethylene net cover E1, an internal support, and a seedling collection net core E4. The net cover E1 is a cylindrical net with closed binding ropes E5 at its top and bottom openings, which allow the seedling collection cage to be opened or closed and to be connected to the top hanging rope and the bottom weight F. The internal support includes annular supports E3 spaced apart inside the cylindrical net and a longitudinal support E2 that runs through the center of the annular supports E3. The two ends of the longitudinal support E2 are fixed by the closed binding ropes E5 at the top and bottom of the cylindrical net, keeping the longitudinal support in the center of the seedling collection cage E. The longitudinal support E2 and the annular support E3 are used to support and fix the cylindrical net. The longitudinal support E2 and the annular support E3 are hollow cylindrical tubes made of polyethylene or polyvinyl chloride, used to support and fix the cylindrical net. The surface of the longitudinal support E2 has spirally spaced locking holes E7 to engage and connect the seedling collection net core.

[0063] like Figure 5 and Figure 6 As shown, the seed collection net core E4 consists of several triangular polyethylene mesh sheets. T-shaped clips E6 are installed at the connection ends between the triangular polyethylene mesh sheets and the longitudinal support E2. The T-shaped clips E6 can engage with the locking holes E7 on the surface of the longitudinal support E2. This means the seed collection net cores E4 are alternately and spirally arranged and movable on the longitudinal support E2 for the attachment and collection of sea urchin seedlings. This design ensures that the triangular polyethylene mesh seed collection net cores E4 are securely installed on the longitudinal support E2 while allowing for some movement, preventing excessive impact from the ocean currents from causing the connection ends of the triangular polyethylene mesh sheets to break. The seed collection net core E4 can also be made of fan-shaped polyethylene mesh.

[0064] In this embodiment, the seedling collection cage is 3m long and 60cm in diameter. The cylindrical netting covering the cage has a mesh size of 12 to 18 meshes. Three ring supports E3 are set inside the cylindrical netting, respectively located 50cm from the top, 50cm from the bottom, and in the middle of the cylindrical netting. The longitudinal support E2 is 3m long and 5cm in diameter, with a hollow internal structure. The surface of the longitudinal support E2 has 34 spiral holes E7 for locking and installing the seedling collection netting core E4. The spacing between adjacent seedling collection netting core E4 polyethylene mesh sheets is 6cm, that is, each seedling collection cage E has 34 sets of triangular polyethylene mesh seedling collection netting cores E4.

[0065] (5) Seedling collection and recovery of seedling collection equipment

[0066] In early September 2020, the sea urchin seedlings in the seed collection cage E grew to a size of 2-3mm. The seed collection cage E was then retrieved, and the top and bottom sealing ropes E5 were opened to remove the seed collection net core E4. The seedling core E4 and the net cover E1 were cleaned and recycled using a washing machine. A total of 1.15 million sea urchin seedlings were collected, completing the seed collection plan.

[0067] Example 2

[0068] Under the same seedling collection conditions as in Example 1, a comparative experiment was conducted on the seedling collection effect of the seedling collection net cage of the present invention and the traditional seedling collection net bag.

[0069] In early June 2020, traditional seedling collection net bag packaging began. Polyethylene netting sheets were divided into sections and packed into seedling collection net bags. The net bags had 18 mesh and were tied with polyethylene rope. 20 bags were packaged per basket, making 300 baskets of seedling collection nets. The 240 seedling collection net cages in Example 1 were assembled and completed in early July due to their simple assembly.

[0070] From July 20 to 30, 2020, in the "fan-shaped" seedling collection field constructed under the same conditions as in Example 1, seedling collection nets and seedling collection cages as in Example 1 were simultaneously placed on the left and right sides of three seedling collection rafts. On average, each seedling collection raft had 100 seedling collection nets and 80 seedling collection cages, for a total of 300 seedling collection nets and 240 seedling collection cages.

[0071] In early September 2020, 300 seedling collection nets and 240 seedling collection net cages from the comparative experiment were collected simultaneously. The detailed comparison of the effects of the two, such as the number of seedlings collected, is shown in Table 1.

[0072] Table 1. Comparison of the effects of seedling collection net cages and traditional seedling collection nets under the same seedling collection environmental conditions.

[0073] quantity Seedling collection quantity Seedling collection quantity per cage (hanging) Seedling collection efficiency Single-cage (hanging) seedling attachment substrate configuration This invention provides a seedling collection net cage. 240 1.15 million pieces 0.48 million pieces 141 pieces / piece 34 pieces / cage Traditional seedling collection net hanging 300 hangers 890,000 pieces 0.30 million pieces 148 pieces / bag 20 bags / hanger

[0074] The seedling collection net cage of this invention increases the seedling collection capacity by 29.21% compared to the traditional seedling collection net hanging system, with a 60% increase in the seedling collection capacity per cage. The calculated cost of the seedling collection net cage is 25% lower than that of the traditional seedling collection net hanging system. Furthermore, during the seedling separation stage, the seedling collection net cage of this invention saves a significant amount of labor compared to the traditional seedling collection net hanging system, exhibiting characteristics such as time-saving, labor-saving, high efficiency, and low cost. Therefore, it can be widely promoted and used.

[0075] This invention solves the problem of difficult hanging and binding of seedling collection nets in previous methods. A "fan-shaped" seedling collection area model accurately determines the collection area and is equipped with a seedling collection device. The new standardized component combination of the seedling collection net cage, with an internal annular support plate, effectively supports the area of ​​the collection cage, providing more collection space for the same collection area. Meanwhile, the design of the cylindrical support rod, the fan-shaped seedling collection net, and the integrated external seedling collection cover facilitates assembly efficiency during the collection process. The "spiral" fan-shaped polyethylene net design saves on the amount of seedling attachment substrate and provides sufficient space between the net sheets to prevent seedlings from falling off during collection due to friction. This invention optimizes seedling collection efficiency, saves on collection costs, reduces labor intensity, and improves collection results, representing a technological advancement and improvement over traditional seedling collection methods.

[0076] The seedling collection method and apparatus of the present invention can also be used to collect scallop and conch seedlings.

[0077] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for natural seedling collection of sea urchin in sea area, characterized in that, The steps are as follows: (1) Selection of seedling collection point According to the statistical amount of sea urchin biological resources in the annual collection process, the sea urchin biological resource advantage area is selected as the seedling collection point; the sea urchin biological resource advantage area refers to the sea area where the algal resources are rich and the sea urchin biological resources amount reaches or exceeds 0.15 kg / ㎡; (2) Construction of "fan-shaped" seedling collection field Taking the seedling collection point at the near-shore end as the center and the connecting line of the seedling collection point at the near-shore end and the other two seedling collection points in the peripheral direction as the radius, the seedling collection platform raft is erected parallel between the "fan-shaped" radius to construct the "fan-shaped" seedling collection field; The seedling collection device of the "fan-shaped" seedling collection field is arranged according to the planned seedling collection amount: S=d*n*r*1000 Wherein: S represents the total amount of seedling collection, unit: pieces; d represents the density of four-arm larvae, unit: pieces / m3; n represents the average number of net cages on each seedling collection platform raft, unit: pieces; r represents the number of seedling collection platform rafts, unit: tables; (3) Regular monitoring of seedling collection point The mature sea urchin, i.e. the parent sea urchin gonad development and the number of planktonic larvae at the seedling collection point are regularly monitored, when the average gonad index of the parent sea urchin reaches 20%-25% or the density of four-arm larvae reaches 2-5 pieces / m3, the seedling collection device is arranged on the platform raft of the "fan-shaped" seedling collection field; the average gonad index = gonad weight / body weight*100%; (4) Arrangement of seedling collection device The seedling collection device adopts seedling collection net cages, a plurality of seedling collection net cages are hung and fixed on the seedling collection platform raft of the "fan-shaped" seedling collection field, and the seedling collection net cage hanging water layer is 3-5 m underwater; (5) Seedling collection and seedling collection device recovery After the seedling collection net cage is arranged for 40-60 days, when the sea urchin seedling in the seedling collection net cage grows to 2-3 mm in size, the seedling collection net cage is recovered, the sea urchin seedling attached in the seedling collection net cage is washed and recovered, and the seedling collection work is completed.

2. The method for natural seed collection of sea urchin according to claim 1, wherein, The parallel erected platform raft spacing of the "fan-shaped" seedling collection field is 3-5 m.

3. The natural seed collection method of sea urchin sea area according to claim 1, characterized in that, The spacing between adjacent seedling collection net cages on the seedling collection platform raft of the "fan-shaped" seedling collection field is not less than 0.3 m.

4. The method for natural seed collection of sea urchin according to claim 1, wherein, The seedling collection net cage comprises a polyethylene material net cage cover, an internal support and a seedling collection net core; the net cage cover is a cylindrical net cover, closed binding ropes are arranged at the top and bottom openings of the cylindrical net cover respectively, the opening or closing of the seedling collection net cage is realized through the closed binding ropes, and the connection with the top lifting rope and the bottom falling stone is realized; the internal support comprises annular supports arranged at intervals in the cylindrical net cover and a longitudinal support penetrating the center of the annular supports, the longitudinal support is fixed at both ends through the closed binding ropes at the top and bottom of the cylindrical net cover, so that the longitudinal support is kept at the center position of the seedling collection net cage, and the longitudinal support and the annular support are used for supporting and fixing the cylindrical net cover; the seedling collection net core is a plurality of triangular or fan-shaped polyethylene meshes, the seedling collection net core is movably connected to the longitudinal support, is alternately and staggeringly arranged in a spiral shape on the longitudinal support, and is used for sea urchin seedling attachment and collection.

5. The method for natural seed collection of sea urchin according to claim 4, wherein, The internal support of the seedling collection net cage is a hollow structure circular tube made of polyethylene or polyvinyl chloride material.

6. The method for natural seed collection of sea urchin according to claim 5, wherein, The longitudinal support of the hollow structure is provided with spiral-shaped interval arranged clamping holes on the surface, the seedling collection net core is provided with a T-shaped buckle at the connection end with the longitudinal support, and the T-shaped buckle is clamped and connected with the clamping holes on the surface of the longitudinal support.

7. The method for natural settlement of sea urchin larvae in sea area according to claim 1, characterized in that, The method for monitoring the quantity of the planktonic larvae is as follows: 1m3 water sample is taken from 3m-5m water layer under water by using a plankton net every week at the seedling collecting point during the breeding period of the sea urchin, and the density of the four-arm larvae in the water sample is observed.

8. The method for natural settlement of sea urchin larvae in sea area according to claim 1, characterized in that, The method can be used for collecting scallop and conch seedlings.

Images