CN120530913A - Oyster-sea urchin-undaria seaweed three-dimensional ecological aquaculture method suitable for muddy seabed - Google Patents

Abstract

The invention belongs to the field of mariculture, and particularly relates to a three-dimensional ecological oyster-sea urchin-undaria pinnatifida culture method suitable for silt seafloors. The method comprises the following steps of (1) oyster reef construction, namely hanging and culturing oysters in a sediment sea area, throwing and culturing oysters to the sea floor to form oyster reefs, (2) undaria pinnatifida culture, namely culturing undaria pinnatifida above the oyster reefs by adopting a buoyant raft, (3) sea urchin seedlings throwing, namely taking a natural pore structure of the oyster reefs as a sea urchin habitat, throwing sea urchin seedlings, and (4) sedimentation feeding management, namely dropping the cultured undaria pinnatifida to the sea floor sea urchin habitat as sea urchin baits. Compared with the traditional single culture mode, the invention improves the utilization rate of the culture space by 3.2 times, reduces the bait cost by 65 percent, reduces the nitrogen and phosphorus load of the water body by 40 percent, simultaneously realizes the quick growth speed of the sea urchins, the improvement of the survival rate, the reduction of the organic matter content of sediment in the oyster zone and the high-efficiency utilization of the fresh undaria pinnatifida, and has obvious economic benefit and ecological benefit.

Description

Oyster-sea urchin-undaria pinnatifida three-dimensional ecological breeding method suitable for muddy sandy seafloor

Technical Field

The invention belongs to the field of mariculture, and particularly relates to a three-dimensional ecological oyster-sea urchin-undaria pinnatifida culture method suitable for silt seafloors.

Background

In the mariculture industry, sediment seafloor is a key bottleneck for limiting large-scale culture of benthos such as sea urchins due to lack of a stable hard substrate. The existing research shows that if the sea urchin culture adopts the traditional net cage mode, high equipment maintenance and manual management cost is required to be continuously input, the sea urchin escape rate is high and the survival rate is low due to the fact that the bottom sowing culture cannot provide a proper habitat environment, meanwhile, shells of the oyster are piled to form the biological reef with an ecological function in the natural growth process, the three-dimensional space resources of the reef body are not systematically developed by the existing culture technology, so that space waste and ecological value are idle, in addition, the undaria pinnatifida is used as high-quality natural bait for the sea urchin, the traditional manual harvesting and feeding mode has the problems of high manual harvesting cost, large transportation loss and the like, and the residual bait rate of about 35% can lead to substrate pollution risk and threaten culture ecological balance. At present, researches on the problems are focused on optimization of single species cultivation technology, and a systematic solution based on species niche complementation is not formed.

The prior art (such as CN 111758624A) provides a perching space for sea products by bottom sowing oyster strings, but has the defects that (1) the oyster strings are utilized to directly bottom sowing to construct sea reefs, a solution is not provided for the problem that the muddy sand seabed lacks a hard substrate, sea urchins still face the problems of unstable perching and high escape rate in loose sediment, (2) the baits depend on artificial feeding of other algae, the efficiency is low, the problem of the shortage of baits in high-temperature seasons in summer is not solved, and (3) the bottom sowing mode of the oyster strings only realizes planar resource utilization, does not develop a three-dimensional space and has limited ecological benefits.

Disclosure of Invention

Aiming at the technical problems, the invention provides a three-dimensional ecological oyster-sea urchin-undaria pinnatifida cultivation method suitable for muddy sandy seafloor. Compared with the traditional single culture mode, the invention improves the utilization rate of the culture space by 3.2 times, reduces the bait cost by 65 percent, reduces the nitrogen and phosphorus load of the water body by 40 percent, and simultaneously realizes the high-efficiency utilization of the sea urchin, the increase of the survival rate, the reduction of the sediment organic matter content in the oyster region and the fresh undaria pinnatifida.

The invention is realized by the following technical scheme:

The oyster-sea urchin-undaria pinnatifida three-dimensional ecological breeding method suitable for muddy sand seafloor comprises the following steps of:

(1) The construction of oyster reefs, namely hanging and raising oysters in a sediment sea area, and throwing and raising oysters on the sea floor to form oyster reefs;

(2) Culturing undaria pinnatifida by adopting a floating raft above the oyster reef;

(3) Sea urchin seedling throwing, namely utilizing a natural pore structure of the oyster reef as a sea urchin habitat to throw sea urchin seedlings;

(4) And (3) sedimentation feeding management, namely vertically lowering the cultured undaria pinnatifida to a sea urchin perching area to serve as sea urchin baits.

Further, the step (1) specifically includes:

(1.1) arranging culture rafts, namely arranging the single culture rafts in parallel at intervals of 6-8m in a sediment sea area, wherein the net length of each single culture raft is 60-80m, the floating stems are fixed to the sea floor through pile cables and deep-inserting brackets, and a plurality of floating balls are bound on the floating rafts;

(1.2) oyster hanging cultivation, namely selecting crassostrea gigas as a cultivation variety, adopting oyster shells or shells as attachment bases to collect seedlings, culturing young shells attached to the attachment bases until the shells are 500-600 mu m long, then moving the young shells to a natural sea area, and hanging cultivation on floating stems according to the interval of 8-15cm between the attachment bases;

During the collection, the rope heads of 10 to 15 cultivation ropes are bound and then fixed on the sea bottom through anchor;

(1.3) reef formation, namely, continuously throwing the cultured oyster cultivation ropes for a plurality of years, continuously growing and attaching the oyster, and mutually stacking shells to form the oyster reef.

Further, in the step (1.1), the deep-inserting bracket is made of traditional wood piles, corrosion-resistant metal or high-strength engineering plastic materials.

Further, in the step (1.3), the oyster cultivation ropes after cultivation are continuously thrown in for 2-3 years, and the oyster reef construction work is completed when the oyster reef height is confirmed to protrude out of the seabed sediment surface by more than or equal to 50cm and the porosity is more than or equal to 60%.

Further, the step (2) specifically includes:

(2.1) culturing undaria pinnatifida autumn seedlings, namely after the construction of oyster reefs is completed, when the water temperature of the sea area in the 9 th and the last ten days of each year is reduced to be less than 20 ℃, horizontally hanging undaria pinnatifida sporophyte seedling ropes between two adjacent rows of laid floating rafts, wherein the horizontally culturing density is 20-30 plants/m;

(2.2) spring seedling cultivation of undaria pinnatifida, namely supplementing the gametophyte seedlings of the undaria pinnatifida cultivated by raft in the middle and late 2 months of the year, wherein the parallel cultivation density is 20-30 plants/m.

Further, the buoyant raft for cultivating undaria pinnatifida is made of polyethylene material.

Further, the step (3) specifically includes:

(3.1) selecting sea urchin seedlings, namely selecting the sea urchin with the patinopsis yearly horse manure or the sea urchin with the purple manure as a breeding object;

selecting a put-in variety according to the sea area temperature, and sowing the purple sea urchin at the bottom when the sea area temperature exceeds 25 ℃, and sowing the horse dung sea urchin at the bottom when the sea area temperature does not exceed 25 ℃;

(3.2) sea urchin seedlings are put in the sea by taking the natural pore structure of the oyster reef as a sea urchin habitat;

The high temperature period in summer is avoided when the sea urchin seedlings are put in, the sea urchin seedlings are put in when the water temperature falls back below 15 ℃ from the last ten days of 11 months to the last ten days of 12 months, the putting specification is 30-50 g/piece, the shell diameter is 2.5-3.5cm, and the stocking density is 15-20 pieces/m < 2 >.

Further, the step (4) specifically includes:

when the algae for culturing the undaria pinnatifida grows to be more than or equal to 50cm, unwinding part of the undaria pinnatifida culturing ropes, connecting the middle parts of 3-5 culturing ropes with the pendant through the binding ropes, and naturally dropping the undaria pinnatifida culturing ropes to a sea urchin perching area to serve as sea urchin baits;

According to the actual feeding condition of the sea urchins, the feeding frequency and the feeding amount are adjusted to ensure that the bait supply is matched with the sea urchins.

Further, when the undaria pinnatifida is used for feeding sea urchins, the feeding amount is fed according to 8-10% of the weight of the sea urchins per day.

The beneficial technical effects of the invention are as follows:

The three-dimensional ecological breeding method provided by the invention innovates the sea urchin perching mode, abandons the traditional artificial frame, utilizes the oyster reef natural structure to provide perching places for sea urchins, saves equipment cost by about 40%, and improves the survival rate of the sea urchins from 30% to more than 85% in the traditional bottom sowing mode.

The three-dimensional ecological breeding method provided by the invention innovates bait supply, realizes annual bait supply through breeding and throwing of undaria pinnatifida seedlings (sporophyte seedlings and gametophyte seedlings) in spring and autumn, omits a manual harvesting link, and improves the bait utilization rate from 65% to 88%.

The three-dimensional ecological breeding method provided by the invention has remarkable ecological benefits, reduces pollution of artificial frame materials to marine environment, effectively reduces nitrogen and phosphorus load of water body and organic matter content of sediment, and maintains ecological balance of a breeding area.

Drawings

FIG. 1 is a diagram showing the cultivation of undaria pinnatifida in an embodiment of the invention;

FIG. 2 is a schematic diagram showing a three-dimensional ecological cultivation underwater side view of oyster-sea urchin-undaria pinnatifida suitable for muddy sand seafloor in the embodiment of the invention;

The floating ball type sea urchin reef comprises the following components of a floating ball, a floating stem, a pile cable, a deep insertion type bracket, a undaria pinnatifida, a floating raft, a oyster, a sea urchin and an oyster reef.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

On the contrary, the invention is intended to cover any alternatives, modifications, equivalents, and variations as may be included within the spirit and scope of the invention as defined by the appended claims. Further, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. The present invention will be fully understood by those skilled in the art without the details described herein.

The invention provides a three-dimensional ecological breeding method of oyster-sea urchin-undaria pinnatifida suitable for muddy sand seafloor, which comprises the following steps:

(1) The construction of oyster reefs, namely hanging and raising oysters in a sediment sea area, and throwing and raising oysters on the sea floor to form oyster reefs;

(2) Culturing undaria pinnatifida by adopting a floating raft above the oyster reef;

(3) Sea urchin seedling throwing, namely utilizing a natural pore structure of the oyster reef as a sea urchin habitat to throw sea urchin seedlings;

(4) And (3) sedimentation feeding management, namely vertically lowering the cultured undaria pinnatifida to a sea urchin perching area to serve as sea urchin baits.

The step (1) specifically comprises:

(1.1) arranging culture rafts, namely arranging the single culture rafts in parallel at intervals of 6-8m in a sediment sea area, wherein the net length of each floating stem 2 of each single culture raft is 60-80m, the floating stems 2 are fixed to the sea floor through pile cables 3 and deep-inserting supports 4, a plurality of floating balls 1 are bound on the floating rafts, and the deep-inserting supports 4 are specifically made of traditional wood piles, corrosion-resistant metals or high-strength engineering plastic materials.

(1.2) Oyster hanging cultivation, namely selecting a crassostrea gigas with high growth speed and strong adaptability as a cultivation variety, adopting oyster shells or shells as an attachment base (the surface of the attachment base is provided with a rope penetrating hole, and ropes are penetrated inside the attachment base), picking seedlings, culturing young shells attached to the attachment base until the shell length is 500-600 mu m, then moving the young shells to a natural sea area, and hanging cultivation on floating stems according to the interval of 8-15cm between the attachment bases;

During the collection, the rope heads of 10 to 15 cultivation ropes are bound and then fixed on the sea bottom through anchor;

The cultivation rope for hanging cultivation is divided into an upper section and a lower section, wherein the upper section is 3m long, the oysters attached to the upper section are harvested and landed as commercial oysters after growing, the lower section is 2m long, rope heads of every 10-15 cultivation ropes are bound during harvesting, and the lower section is fixed on the sea floor through anchor and used as a material for constructing oyster reefs.

(1.3) Reef formation, namely, continuously throwing the cultured oyster cultivation ropes for a plurality of years, continuously growing and attaching the oyster, and mutually stacking shells to form the oyster reef. Specifically, the oyster cultivation ropes after cultivation are continuously put in for 2-3 years, and the diving observation confirms that the oyster reef protrudes out of the sediment surface of the seabed by more than or equal to 50cm (namely, the oyster reef is more than or equal to 50 cm), and the oyster reef building work is completed when the porosity is more than or equal to 60%. The method for fixing the oyster reefs is suitable for silt geology, firm and ecologically friendly.

In this embodiment, the step (2) specifically includes:

(2.1) undaria pinnatifida autumn seedling cultivation, namely after the construction of oyster reefs is completed, when the water temperature in the sea area in the 9 th and the last ten days of the year is reduced to be less than 20 ℃, undaria pinnatifida sporophyte seedling ropes are horizontally hung between two adjacent rows of laid floating rafts, and the horizontally cultivation density is 20-30 plants/m, wherein the floating rafts for cultivating undaria pinnatifida are made of high-strength corrosion-resistant polyethylene materials.

(2.2) Spring seedling cultivation of undaria pinnatifida, namely supplementing the gametophyte seedlings of the undaria pinnatifida cultivated by raft in the middle and late 2 months of the year, wherein the parallel cultivation density is 20-30 plants/m. In the seedling rope cultivation process, the growth conditions of the undaria pinnatifida are regulated and controlled by periodically monitoring environmental parameters such as water quality, illumination and the like, so that healthy growth of the undaria pinnatifida is ensured.

In this embodiment, the step (3) specifically includes:

(3.1) selecting sea urchin seedlings, namely selecting the sea urchin with the patinopects with quick growth speed and high economic value or the sea urchin with the patinopects with the purple as a breeding object;

selecting a put-in variety according to the sea area temperature, and sowing the purple sea urchin at the bottom when the sea area temperature exceeds 25 ℃, and sowing the horse dung sea urchin at the bottom when the sea area temperature does not exceed 25 ℃;

(3.2) sea urchin seedlings are put in the sea by taking the natural pore structure of the oyster reef as a sea urchin habitat;

The high temperature period in summer is avoided when the sea urchin seedlings are put in, the sea urchin seedlings are put in when the water temperature falls back below 15 ℃ from the last ten days of 11 months to the last ten days of 12 months, the putting specification is 30-50 g/piece, the shell diameter is 2.5-3.5cm, and the stocking density is 15-20 pieces/m < 2 >. Specifically, when sea urchin seedlings are put in, asparagus is clamped by ropes and then put in the sea floor to serve as initial bait for bottom sowing of sea urchin.

In this embodiment, the step (4) specifically includes:

When the algae for culturing the undaria pinnatifida grows to be more than or equal to 50cm (when sporophytes Miao Yaozai grow to be more than or equal to 50cm in late stage of the month, gametophytes Miao Yaozai grow to be more than or equal to 50cm in late stage of the month), the culture ropes of part of the undaria pinnatifida are untied, the middle parts of 3-5 culture ropes are connected with the pendant with the weight of more than 500 g/g through the binding ropes, so that the culture ropes of the undaria pinnatifida naturally drop to the sea urchin perching area to serve as sea urchin baits, the feeding frequency and the feeding quantity are adjusted according to the actual feeding condition of the sea urchins so as to ensure that the baits are supplied to be matched with the requirements of the sea urchin, and the material circulation and ecological balance of a culture system are maintained.

In the invention, the autumn seedlings of the undaria pinnatifida cultivated in the middle and late 9 months of the year can be fed from the beginning of the last 11 months until the feeding of all the baits of the undaria pinnatifida (the undaria pinnatifida cultivated in the autumn) is finished in the last 5 months of the year, the spring seedlings of the undaria pinnatifida cultivated in the middle and late 2 months of the year can be fed from the beginning of the last 5 months until the feeding of all the baits of the undaria pinnatifida (the undaria pinnatifida cultivated in the spring) is finished in the last 11 months of the year, the undaria pinnatifida cultivated in the spring fully utilizes the idle position of the undaria pinnatifida after the harvest, simultaneously solves the problem of lack of high-quality baits of the sea urchin after 6 months, improves the survival rate of the sea urchin in summer, realizes the feeding of all-year baits through cultivation and throwing of the undaria pinnatifida cultivated in the spring and autumn (the sporophyte and gametophyte) and the artificial harvesting link is omitted, and the utilization rate of the baits is increased from 65% to 88%. During feeding, sea urchins reaching commodity specifications are harvested in a large catching and small retaining mode.

In the invention, if the fresh undaria pinnatifida bait is lacking, the rope with the asparagus or the floating Sargassum is put on the sea floor to feed, specifically, the rope with the asparagus can be put on the sea floor in a high-temperature period, and the rope with the floating Sargassum is put on the sea floor to feed sea urchins in a low-temperature period.

In the embodiment, when the undaria pinnatifida is used for feeding sea urchins, the feeding amount is fed according to 8-10% of the weight of the sea urchins per day.

The implementation area is taken as an implementation area of a sandy sea area (the water depth is 10 m) of the Shandong Chengwan, and the specific implementation steps are as follows:

Oyster reef foundation

In the culture area of Mulberry gulf, 5 parallel undaria pinnatifida (or kelp) single culture rafts are selected as the implementation area.

And 2023, 6 months, selecting crassostrea gigas as a breeding variety, taking scallop shells as an attachment base for indoor artificial seedling collection, and moving the crassostrea gigas to a natural sea area after the attached young shellfish is cultured to 550 mu m long. The seedling attaching base spacing is set to be 10cm by adopting a rope-extending type hanging and raising mode, and the hanging and raising rope is divided into an upper section 3m and a lower section 2m. And putting oyster fries into each rope according to the density of 350, and periodically monitoring environmental parameters such as water temperature, salinity, dissolved oxygen and the like in the cultivation process.

And 2024, 9 months later, binding rope heads of 10 culture ropes, and fixing the ropes on the sea bottom through anchor, wherein oyster shells are mutually piled up to form an oyster reef cluster with the average height of 50cm and the porosity of more than or equal to 60%, so that a foundation is laid for the subsequent culture links.

(II) Undaria pinnatifida sporophyte seedling lower sea

And 2024, hanging undaria pinnatifida sporophyte ropes (undaria pinnatifida autumn seedlings) between floating rafts, wherein the sea size of the seedlings is 15cm, the seedling clamping density is 20 plants/m, and monitoring parameters such as water quality, illumination and the like according to growth conditions during cultivation.

(III) sea urchin seedling throwing in

In 2024, for 11 months, as the temperature of Sang Gou bay area is lower than 25 ℃, the sea urchin with the patinopsis horse manure is selected as a breeding object, the feeding specification is 30 g/sea urchin (the shell diameter is about 2.5 cm), sea urchin seedlings are directly scattered into the natural pore structure of the oyster reef cluster according to the density of 18 sea urchin seedlings/m 2, and the reef space is fully utilized to provide a habitat for the sea urchin.

(IV) bait feeding management

In the late 11 month, the growth of the undaria pinnatifida algae is over 50cm, part of undaria pinnatifida cultivation ropes are untied, and the middle parts of 3-5 seedling ropes are connected with 500 g/weight stone through binding ropes, so that the undaria pinnatifida algae naturally drop to the sea urchin perching area. Feeding is carried out according to 8 percent of the sea urchin weight per day, and feeding frequency is dynamically adjusted according to the feeding condition of the sea urchin, so that the efficient utilization of baits is realized.

(V) supplementing gametophyte seeds of undaria pinnatifida

And 2025, 2 months later, culturing the gametophyte seedling of undaria pinnatifida (spring seedling of undaria pinnatifida) in the sea. In the cultivation process, the same offshore cultivation management mode as that of the sporophyte seedlings is adopted, and the cultivation conditions such as the position of the floating raft and the density of seedling ropes are timely adjusted by periodically monitoring the pH value, the salinity, the nitrogen and phosphorus content, the illumination intensity, the water temperature and other environmental parameters of water quality, so that the growth environment of the sporophyte seedlings is continuously optimized.

By the middle and late 5 months of 2025, the sporophyte seedlings cultivated in the earlier stage are completely finished according to the plan. At this point, the gametophyte seedlings have grown to 60 cm and reached the appropriate feeding length. According to the established bait casting mode, unwinding part of gametophyte seedling cultivation ropes, connecting the middle parts of 3-5 seedling ropes with 500 g/g of pendant stone by using the binding ropes, and naturally dropping the seedling ropes to a sea urchin perching area to serve as sea urchin baits. Meanwhile, according to the actual feeding condition of the sea urchins, the feeding frequency and the feeding quantity are dynamically adjusted, the matching of bait supply and sea urchins needs is ensured, and the material circulation and ecological balance in the culture system are further maintained.

(Six) sea urchin harvesting

Harvesting sea urchins meeting commodity specifications began from month 6 of 2025. The commodity specification of the sea urchin is set to be that the weight is more than or equal to 80g, the shell diameter is more than or equal to 4.5cm, a diving manual catching mode is adopted, the principle of catching big and small is followed, sea urchin individuals meeting the specification are preferentially picked, and smaller individuals are reserved to continue growing. In the harvesting process, the harvesting quantity and weight of sea urchins are recorded, and the quantity and growth conditions of the residual sea urchins in the cultivation area are evaluated so as to reasonably plan a subsequent cultivation management strategy.

(Seventh) implementation effect

Through the practice of one cultivation period, the ecological cultivation method achieves remarkable effects:

The sea urchin cultivation benefit is improved, namely the survival rate of the sea urchin is improved to 92 percent, compared with 78 percent of the traditional net cage cultivation, the survival rate is obviously improved, and the cultivation risk is effectively reduced;

the organic matter content of the sediment in the oyster area is reduced by 41 percent, which indicates that the filter feeding effect of the oyster effectively purifies the water quality in the cultivation area and improves the submarine environment;

the utilization rate of the undaria pinnatifida residual bait reaches 85%, the pollution of the residual bait to the water body is reduced, meanwhile, high-quality natural bait is provided for sea urchins, and the material circulation and ecological balance in the culture system are realized.

According to the three-dimensional ecological breeding method provided by the invention, the space utilization of the oyster reefs, the inhabitation requirement of sea urchins and the bait value of the undaria pinnatifida are subjected to ecological niche coordination, so that a breeding mode with economic benefit and environmental friendliness is constructed. According to the invention, the attachment stability of the sea urchins is obviously improved through the manually constructed oyster reefs, and the problems of unstable inhabitation and high escape rate of the sea urchins in loose sediment are effectively solved. Meanwhile, the novel double-stubble undaria pinnatifida is adopted, namely, through an alternate culture mode of autumn seedlings (11-month feeding) and spring seedlings (2-month supplementing in the next year), the problem of sea urchin bait shortage in a 6-8 month high temperature period can be solved, the undaria pinnatifida residual bait which naturally drops can be cooperatively consumed by oysters and sea urchins, the bait utilization rate can be improved to 88% from 65%, and the labor cost is reduced by 65%. In addition, nitrogen and phosphorus in the water body can be absorbed in the undaria pinnatifida cultivation process, and the undaria pinnatifida cultivation process is cooperated with the filter feeding effect of oyster, so that the water quality can be effectively regulated and controlled, and the ecological benefit is remarkably improved.

The invention creatively utilizes the biological reefs formed by stacking cultured adult oysters through artificial modeling, solves the problem that sea urchins can not be sown at bottom due to lack of hard adhesion base, and realizes the material circulation in a culture system through the nutrition cascade of undaria pinnatifida and sea urchins. The method forms a three-dimensional ecological culture mode of sessile organisms-benthos-large algae through three core steps of oyster reef base construction, sea urchin three-dimensional perching system construction and undaria pinnatifida bait supply system integration. Compared with the traditional single culture mode, the invention improves the utilization rate of the culture space by 3.2 times, reduces the bait cost by 65 percent, reduces the nitrogen and phosphorus load of the water body by 40 percent, simultaneously realizes the high growth speed of the sea urchins, improves the survival rate, reduces the organic matter content of sediment in the oyster region and efficiently utilizes the fresh undaria pinnatifida, has obvious economic benefit and ecological benefit, and provides a sustainable development technical scheme for the mariculture of the muddy sea region.

The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims (9)

1. The oyster-sea urchin-undaria pinnatifida three-dimensional ecological breeding method suitable for muddy sand seafloor is characterized by comprising the following steps of:

(1) The construction of oyster reefs, namely hanging and raising oysters in a sediment sea area, and throwing and raising oysters on the sea floor to form oyster reefs;

(2) Culturing undaria pinnatifida by adopting a floating raft above the oyster reef;

(3) Sea urchin seedling throwing, namely utilizing a natural pore structure of the oyster reef as a sea urchin habitat to throw sea urchin seedlings;

(4) And (3) sedimentation feeding management, namely vertically lowering the cultured undaria pinnatifida to a sea urchin perching area to serve as sea urchin baits.

2. The oyster-sea urchin-undaria pinnatifida stereoscopic ecological breeding method suitable for muddy seafloor according to claim 1, wherein the step (1) specifically comprises the following steps:

(1.1) arranging culture rafts, namely arranging the single culture rafts in parallel at intervals of 6-8m in a sediment sea area, wherein the net length of each single culture raft is 60-80m, the floating stems are fixed to the sea floor through pile cables and deep-inserting brackets, and a plurality of floating balls are bound on the floating rafts;

(1.2) oyster hanging cultivation, namely selecting crassostrea gigas as a cultivation variety, adopting oyster shells or shells as attachment bases to collect seedlings, culturing young shells attached to the attachment bases until the shells are 500-600 mu m long, then moving the young shells to a natural sea area, and hanging cultivation on floating stems according to the interval of 8-15cm between the attachment bases;

During the collection, the rope heads of 10 to 15 cultivation ropes are bound and then fixed on the sea bottom through anchor;

(1.3) reef formation, namely, continuously throwing the cultured oyster cultivation ropes for a plurality of years, continuously growing and attaching the oyster, and mutually stacking shells to form the oyster reef.

3. The method for three-dimensional ecological cultivation of oyster-sea urchin-undaria pinnatifida suitable for muddy seafloor according to claim 2, wherein in the step (1.1), the deep-inserting type bracket is made of traditional wood piles, corrosion-resistant metal or high-strength engineering plastic materials.

4. The method for three-dimensional ecological cultivation of oyster-sea urchin-undaria pinnatifida suitable for muddy seafloor according to claim 2, wherein in the step (1.3), the oyster cultivation ropes after cultivation are continuously put in for 2-3 years, and the oyster reef is constructed when the oyster reef height protrudes out of the seafloor sediment surface by more than or equal to 50cm and the porosity by more than or equal to 60% through diving observation and confirmation.

5. The oyster-sea urchin-undaria pinnatifida stereoscopic ecological breeding method suitable for muddy seafloor according to claim 1, wherein the step (2) specifically comprises the following steps:

(2.1) culturing undaria pinnatifida autumn seedlings, namely after the construction of oyster reefs is completed, when the water temperature of the sea area in the 9 th and the last ten days of each year is reduced to be less than 20 ℃, horizontally hanging undaria pinnatifida sporophyte seedling ropes between two adjacent rows of laid floating rafts, wherein the horizontally culturing density is 20-30 plants/m;

(2.2) spring seedling cultivation of undaria pinnatifida, namely supplementing the gametophyte seedlings of the undaria pinnatifida cultivated by raft in the middle and late 2 months of the year, wherein the parallel cultivation density is 20-30 plants/m.

6. The method for three-dimensional ecological cultivation of oyster-sea urchin-undaria pinnatifida suitable for muddy seafloor according to claim 5, wherein the buoyant raft for cultivating undaria pinnatifida is made of polyethylene material.

7. The oyster-sea urchin-undaria pinnatifida stereoscopic ecological breeding method suitable for muddy seafloor according to claim 1, wherein the step (3) specifically comprises the following steps:

(3.1) selecting sea urchin seedlings, namely selecting the sea urchin with the patinopsis yearly horse manure or the sea urchin with the purple manure as a breeding object;

selecting a put-in variety according to the sea area temperature, and sowing the purple sea urchin at the bottom when the sea area temperature exceeds 25 ℃, and sowing the horse dung sea urchin at the bottom when the sea area temperature does not exceed 25 ℃;

(3.2) sea urchin seedlings are put in the sea by taking the natural pore structure of the oyster reef as a sea urchin habitat;

The high temperature period in summer is avoided when the sea urchin seedlings are put in, the sea urchin seedlings are put in when the water temperature falls back below 15 ℃ from the last ten days of 11 months to the last ten days of 12 months, the putting specification is 30-50 g/piece, the shell diameter is 2.5-3.5cm, and the stocking density is 15-20 pieces/m < 2 >.

8. The oyster-sea urchin-undaria pinnatifida stereoscopic ecological breeding method suitable for muddy seafloor according to claim 1, wherein the step (4) specifically comprises the following steps:

when the algae for culturing the undaria pinnatifida grows to be more than or equal to 50cm, unwinding part of the undaria pinnatifida culturing ropes, connecting the middle parts of 3-5 culturing ropes with the pendant through the binding ropes, and naturally dropping the undaria pinnatifida culturing ropes to a sea urchin perching area to serve as sea urchin baits;

According to the actual feeding condition of the sea urchins, the feeding frequency and the feeding amount are adjusted to ensure that the bait supply is matched with the sea urchins.

9. The method for three-dimensional ecological cultivation of oyster-sea urchin-undaria pinnatifida suitable for muddy sandy seafloor according to claim 1, wherein when the undaria pinnatifida is used for feeding sea urchins, the feeding amount is 8-10% of the weight of the sea urchins per day.