Method for artificial domestication, maturation promotion, spawning induction and egg bag collection of hedge phoenix snails

Abstract

The invention belongs to the technical field of large-scale shellfish offspring seed cultivation, and discloses a method for artificial domestication, ripening promotion, spawning induction and egg bag collection of festival snails, the optimal food and bait combination of the festival snails is successfully found out through experiments, sufficient algae bait is cultured by adopting an artificial culture mode, the natural living environment of the festival snails is simulated, and the festival snails can be bred in a large scale. The artificial domestication of the snails is successfully completed. The method is similar to other shellfish ripening, and the purpose of ripening can be achieved by increasing the bait amount and enhancing the nutrition of parent snails. According to the method, the problem of spawning induction of the snails is efficiently solved through a simulated ecological breeding combination method of reducing salinity, providing attachments such as fine sand and the like. By means of the method, artificial domestication of the hedge snails is achieved for the first time in the world, the hedge snails completely adapt to the artificial breeding environment, artificial maturity promoting and spawning inducing work is completed for the first time, the egg laying amount is large, the quality is high, and solid foundation support is provided for subsequent artificial breeding of the hedge snails.

Description

Technical Field

[0001] The invention belongs to the technical field of large-scale shellfish seed cultivation, and more specifically, relates to a method for artificially domesticating, accelerating maturation and induced spawning of water snails and collecting their egg sacs. Background Art

[0002] Strombus luhuanus, commonly known as red-mouthed snail or strawberry snail, is named for the orange-red color of the inside of its shell. It belongs to the class Gastropoda, order Mesogastropoda, family Strombidae, and genus Strombus. It lives in the intertidal zone to the bottom of shallow sea sand, gravel or coral reefs, and is distributed in tropical and subtropical Indo-Pacific waters from the Boso Peninsula in Japan in the north to the Philippines in the south, to the west coast of Indonesia and Australia, and east to the Fiji Islands. In China, it has been reported in Taiwan Province, Huidong and Dapeng in Daya Bay, Guangdong, Xincun Town in Lingshui, Hainan, Xisha Islands, and Weizhou Island in Guangxi. Because of its delicious meat and rich nutrition, Strombus luhuanus is widely loved by coastal residents and is a common traditional delicacy.

[0003] In China, the distribution of hedge snails in Huidong, Shangchuan Island, and Naozhou Island, where they were once reported, is now hard to find. They are only occasionally found in Nan'ao Town, Shenzhen. Although they are still distributed in coastal areas such as Lingshui and Sanya in Hainan, their number has dropped sharply. Therefore, the research on restoring the population of hedge snails through artificial breeding technology is of great significance. Since hedge snails mainly live in deep water areas and have high requirements for bottom and water quality, there are currently no successful experimental studies on artificial domestication of hedge snails in the world. Carrying out artificial domestication and maturation promotion of hedge snails can lay a solid foundation for artificial breeding, resource recovery, and proliferation and release of hedge snails. Summary of the invention

[0004] In order to make up for the deficiencies in the prior art, the present invention provides a method for artificially domesticating, ripening and induced spawning of Pteris fasciatus.

[0005] The second object of the present invention is to provide a method for collecting egg sacs of Pteris fasciatus.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for artificially domesticating, accelerating maturation and inducing spawning of Pteris fasciatus, comprising the following steps:

[0008] S1. Cleaning and disinfection: Select a culture pond with moderate light, clean and disinfect it, and also disinfect the algae attachment equipment for later use;

[0009] S2. Bait culture: After the mixed algae are expanded and cultured, they are added to a culture pond prepared in advance to complete the bait culture, wherein the culture pond is injected with sand-filtered seawater with a water depth of 0.5 to 1 m in advance, and microtubes are used for oxygenation, and algae attachment apparatuses are placed in the culture pond in advance; after the mixed algae enter the culture pond, they are first cultured in static water for 3 to 5 days, and then cultured in flowing water. When the algae attachment apparatus is visibly covered with algae, the bait culture is considered to be completed;

[0010] S3, adaptive domestication: During the breeding period, adult snails of the scallops are captured in the natural distribution area and transported out of water at low temperature; then, the adult snails are placed in the breeding pond where the feed has been cultured in S2 and domesticated for 10 to 20 days. When most of the adult snails actively eat, have normal stress reactions, and have normal defecation, they are considered to have adapted to the breeding pond environment and domestication is complete;

[0011] S4. Promote maturation and induce spawning: When 2 or 3 to 5 adult snails are found to be grouped independently, connected head to tail or with shell openings facing each other, increase the amount of feed in the breeding pond and carry out nutritional enhancement. At the same time, spread a layer of fine sand with a thickness of 0.5 to 2 cm on the bottom of the pond to spread and place an attachment base for the adult snails to lay eggs. After 2 to 5 days of nutritional enhancement, reduce the salinity of the seawater in the breeding pond by 1 to 4‰, stop the convection of water, and maintain the reduced salinity overnight, and turn on the convection of water the next day to allow the adult snails to continue laying eggs during the spawning period.

[0012] Preferably, in the above-mentioned method for artificial domestication, ripening and induced spawning of Epipremnum acutum, the mixed algae described in S2 include Chaetoceros, Platyhelminthes, Chrysophyte, diatoms and Cyclotella.

[0013] Preferably, in the above-mentioned method for artificial domestication, ripening and induced spawning of Epipremnum aquatica, when S2 is cultured in flowing water, the water inlet flow rate is 3 to 10 L / min.

[0014] Preferably, in the above-mentioned method for artificially domesticating, ripening and induced spawning of P. fasciatus, the nutritional fortification in step S4 is to add large algae such as Undaria pinnatifida and Enteromorpha into the breeding pond, and the attachment base for the adult snails to lay eggs is Gnaphalium sphaerocephalum and Abalone plate.

[0015] As a specific implementation method, in the above-mentioned method for artificial domestication and maturation and induced spawning of the snail, the size of the culture pond selected by S1 is [length 5-8m×width 2-4m]), the bottom and walls of the pond are cleaned in advance, and strong chlorine (concentration 20-40g / m 3 ) or potassium permanganate (concentration 5-15 g / m 3 ) for disinfection. The algae attachment tools used are abalone baskets and abalone plates, which also need to be soaked overnight for disinfection for one day.

[0016] As a specific implementation method, in the above-mentioned method for artificial domestication, ripening and induced production of water snails, in a breeding pond with a size of [length 5-8m × width 2-4m], each specific algae in the mixed algae is subjected to secondary expansion culture to a volume of about 10-15L, and when the algae species are darker in color, they are poured into the breeding pond; the time for the attached device to be visibly covered with algae varies depending on the convection water culture time and the weather and light conditions, and takes about 4-8 days.

[0017] As a specific implementation, in the method for artificially domesticating, ripening and induced spawning of the above-mentioned snails, the specific operation of low-temperature, out-of-water transportation of the adult snails in S3 is: during the breeding period (late April to late September), 30 to 40 jins, or about 300 adult snails, are captured in the natural distribution sea area. A plurality of pre-frozen mineral water bottles are placed in the transport box and separated from the snails by cloth for transportation.

[0018] As a specific implementation method, in the above-mentioned method for artificial domestication, maturation and induction of spawning of Epipremnum aquaticum, the adult snails in S3 actively eat, have normal stress response, and have normal defecation, which means that most of the adult snails actively extend their mouths and tongues to scrape algae attached to utensils, the bottom of the pond, and the walls, turn over quickly when frightened, and excrete a large amount of spherical or cylindrical feces (about 5 mm in diameter).

[0019] As a specific implementation, in the method for artificial domestication, ripening and induced production of the above-mentioned conch, the amount of large algae such as kelp and enteromorpha described in S4 is 100-300g, the number of caltrops is 50-100 pieces, and the number of abalone plates is 5-15. Adult snails lay eggs continuously from May to July and September to October, with the peak period in May, June and September. The female snail lays 10-20 clusters of eggs each time.

[0020] The present invention also provides a method for collecting egg bags of hedge snails, which comprises collecting the fine sand, the attachment base for laying eggs by adult snails, and the cylindrical and hemp rope-shaped adhesions on the bottom of the pond in step S4 of the above method, and placing them in advance on a basket with an 80-mesh screen to obtain the egg bags of hedge snails.

[0021] The present invention also provides a method for artificially domesticating, accelerating maturation and inducing spawning of the above-mentioned hedge snails, or an application of the method for collecting egg sacs of hedge snails in artificial cultivation of hedge snails.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention also uses artificial cultivation to cultivate a sufficient amount of algae bait, simulates the natural living environment of the snail, and successfully completes the artificial domestication of the snail. Similar to the ripening promotion of other shellfish, the purpose of ripening can be achieved by increasing the amount of bait and strengthening the nutrition of the parent snail. The present invention efficiently solves the problem of induced spawning of the snail by reducing salinity and providing fine sand and other attachments through an ecological cultivation combination method. Through the above method, the artificial domestication of the water snail was solved for the first time in the world, so that the snail can fully adapt to the artificial breeding environment, and the artificial ripening and induced spawning work was completed for the first time. The egg-laying amount is very large and the quality is high, which provides a solid basic support for the subsequent artificial breeding of the snail. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Showing algae cultivation in the pond for breeding water snails, top view of the pond; (A) The bottom and walls of the breeding pond are covered with turquoise macroalgae; (B) The bottom of the pond is covered with brown, filamentous microalgae about 2 mm thick;

[0025] Figure 2 The abalone plates, abalone frames and other attachment devices placed in the aquaculture pond are shown. (A) The attachment plates (red frame) are covered with microalgae (blue arrow); (B) A large number of spongy, soft microalgae grow on the abalone frames;

[0026] Figure 3 Shows the morphology of algae cultured in the aquaculture pond. (A) Microalgae scraped from the abalone basket in the aquaculture pond; (B) The morphology of various algae under a microscope; (C) The morphology of Thalassiosira (Bacillariophyta), the most suitable microalgae food for snails;

[0027] Figure 4 Showing Enteromorpha growing at the bottom of the aquaculture pond;

[0028] Figure 5 Showing the artificial domestication of parent snails in the breeding pond. (A) Parent snails living in a group; (B) Parent snails extend their tongues at the front of their shells (arrows) to scrape algae off the wall; (C) Parent snails feeding on the abalone basket excrete a large amount of cylindrical feces nearby (arrows); (D) Feces excreted by parent snails on the abalone plate (arrows);

[0029] Figure 6 It shows that the parent snails are dispersed into 2 or 3 to 5 individuals for mating between male and female;

[0030] Figure 7 Showing the parent snail laying eggs on fine sand (A), abalone frame (B), wall (C), and abalone plate (D);

[0031] Figure 8 Showing the eggs of the parent snail, (A) the number of eggs laid by a parent snail; (B) the egg bag under the microscope, the larvae inside the membrane can develop to the blastocyst stage;

[0032] Fig. 9Showing the egg sacs collected in a basket, (A) the egg sacs in a cluster; (B) the basket containing the egg sacs floating on the breeding pond. DETAILED DESCRIPTION

[0033] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below in conjunction with specific drawings and embodiments. In the embodiments, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0034] Example 1

[0035] 1. Disinfection of breeding ponds

[0036] Choose a cement pool with moderate light (size: [length 5-8m × width 2-4m]), clean the bottom and walls of the pool, and apply strong chlorine (concentration 20-40g / m 3 ) or potassium permanganate (concentration 5-15 g / m 3 ) for disinfection, together with abalone baskets, abalone plates and other algae-attached utensils, soak them overnight for disinfection for one day.

[0037] 2. Bait culture

[0038] Drain the disinfected water, and then inject sand-filtered seawater with a depth of 0.5 to 1m into the culture pond, and use microtubes for oxygenation. The culture includes common algae such as Chaetoceros, Platyhelminthes, Chrysophytes, Diatoms, and Cyclotella. After the secondary expansion culture, the volume of each algae species is about 10 to 15L. When the algae species are darker in color, pour them into the culture pond.

[0039] Add the cultured mixed algae species to the culture pond. After 3 to 5 days of static water culture in the culture pond, start the flowing water culture with a water flow rate of 3 to 10L / min. When the attached vessels are covered with algae, the bait culture is considered complete. The flowing water culture time varies depending on the weather and light conditions, and takes about 4 to 8 days.

[0040] like Figure 1 , Figure 2 As shown, sufficient algae bait is cultivated and the entire culture pond is light green ( Figure 1 A), the bottom and walls of the pond are covered with green and brown algae ( Figure 1 B). Corrugated board placed in the breeding pond ( Figure 1 A) Abalone Plate Figure 2 A), abalone frame ( Figure 2 B) are covered with spongy, soft algae. These algae include diatoms, green algae, chlorella and other microalgae ( Figure 3 ) and Enteromorpha and other large algae ( Figure 4 ), the algae species are rich and the density is high.

[0041] When the parent snails begin to mate, algae such as Thalassiomorpha and Enteromorpha can be collected from around the breeding farm for nutritional enhancement to accelerate the spawning progress of the parent snails.

[0042] 3. Adaptive domestication

[0043] During the breeding period (late April to late September), about 300 adult snails weighing 30 to 40 kilograms are captured in the naturally distributed sea area. Place multiple pre-frozen mineral water bottles in the transport box, separate them from the snails with cloth, and transport the adult snails at low temperature and out of water. After being transported to the breeding farm, the adult snails are evenly put into the breeding pond where the bait culture is completed in step 2. Domesticate in the breeding pond for 10 to 20 days, observe the feeding, movement, and mating of the adult snails, and check the mortality rate of the adult snails. If most of the adult snails actively extend their tongues to scrape the algae attached to the utensils, the bottom of the pool, and the walls, turn over quickly when frightened, and discharge a large amount of spherical or cylindrical feces (about 5 mm in diameter), it is considered that they have adapted to the breeding pond environment.

[0044] The results are as follows Figure 5 As shown in the figure, the parent snails are in good condition in the culture pond. Except for about 5% mortality caused by transportation stress in the first three days of culture, there is basically no death in the next six months of culture. Parent snails like to live in groups ( Figure 5 A), often gather in sand, rocks, shelters, etc., extend their eyes and tentacles, and can move quickly. The parent snails extend their mouths and tongues to scrape algae attached to the bottom of the pond, walls, etc. ( Figure 5 B). The snail likes to hide during the day and come out at night. When it has enough food, it can excrete cylindrical or round feces with a diameter of about 5mm ( Figure 5 C, D).

[0045] 4. Promote ripening and induce labor

[0046] Observe the mating of adult snails. If 2 or 3 to 5 adult snails are found to be in independent groups, connected head to tail or with their shells facing each other, it means that the adult snails are mating or preparing to fertilize. Figure 6 ). Increase the amount of feed in the breeding pond. Generally, collect 100-300g of large algae such as kelp and enteromorpha from the surrounding breeding ponds and put them into the breeding pond for nutritional enhancement. At the same time, spread a layer of fine sand with a thickness of 0.5-2cm on the bottom of the pond, scatter 50-100 pieces of stone kelp, and place 5-15 abalone plates as an attachment base for adult snails to lay eggs. After feeding for 2-5 days, add fresh water to reduce the salinity of the seawater in the breeding pond by 1-4‰, stop the convection water, and maintain the reduced salinity overnight, and turn on the convection water the next day. Adult snails lay eggs continuously from May to July and September to October, with the peak period in May, June and September. The female snails lay 10-20 clusters of eggs each time.

[0047] 5. Egg sac collection

[0048] The female snails attach to all kinds of substrates, but most of the egg bags are produced on fine sand, followed by caltrops, and a small amount is produced on the bottom of the pond and abalone plates. The egg bags are sticky eggs, which are adhered to the attachments of fine sand to form cylindrical and hemp rope shapes. They are fluffy in appearance and light in weight. There are brown and yellow filamentous egg bags repeatedly wrapped around the dorsal and ventral sides of caltrops, and sometimes the egg bags can adhere multiple pieces of caltrops into a ball. Collect the adhesions together and put them on a basket with an 80-mesh screen placed in advance. The basket floats in the breeding pond. The collected egg bags can be used for the hatching of the hedge snail seedlings.

[0049] The parent snail likes to lay its eggs on fine sand, sticking the fine sand together. The single egg bag is thread-like, and after sticking together, it becomes a ball, fluffy and soft ( Figure 7 A). Sometimes they lay their eggs on the abalone basket frame, wall, abalone board ( Figure 7 B, C, D), the eggs at this time are white in color because there is no sand or other substances sticking to them. Generally, a female snail can produce 10 to 20 strings of egg bags each time ( Figure 8 A), the larvae in the egg sac develop to the blastocyst stage ( Figure 8 B), they become planktonic larvae after hatching. Prioritize the collection of egg bags laid in the sand and gravel, and scoop up the fluffy parts of the sand and put them into a basket with an 80-mesh screen placed in advance ( Fig. 9 A), then tie some foam around the basket and float it on the surface of the pond ( Fig. 9 B) to prepare for further hatching of snail seedlings.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for artificially domesticating, accelerating maturation and inducing spawning of Epipremnum aquatica, characterized in that: The following steps are involved: S1. Cleaning and disinfection: Select a culture pond with moderate light, clean and disinfect it, and also disinfect the algae attachment equipment for later use; S2. Bait culture: After the mixed algae are expanded and cultured, they are added to a culture pond prepared in advance to complete the bait culture, wherein the culture pond is injected with sand-filtered seawater with a water depth of 0.5 to 1 m in advance, and microtubes are used for oxygenation, and algae attachment apparatuses are placed in the culture pond in advance; after the mixed algae enter the culture pond, they are first cultured in static water for 3 to 5 days, and then cultured in flowing water. When the algae attachment apparatus is visibly covered with algae, the bait culture is considered to be completed; S3, adaptive domestication: During the breeding period, adult snails of the scallops are captured in the natural distribution area and transported out of water at low temperature; then, the adult snails are placed in the breeding pond where the feed has been cultured in S2 and domesticated for 10 to 20 days. When most of the adult snails actively eat, have normal stress reactions, and have normal defecation, they are considered to have adapted to the breeding pond environment and domestication is complete; S4. Promote maturation and induce spawning: When 2 or 3 to 5 adult snails are found to be grouped independently, connected head to tail or with shell openings facing each other, increase the amount of feed in the breeding pond and carry out nutritional enhancement. At the same time, spread a layer of fine sand with a thickness of 0.5 to 2 cm on the bottom of the pond to spread and place an attachment base for the adult snails to lay eggs. After 2 to 5 days of nutritional enhancement, reduce the salinity of the seawater in the breeding pond by 1 to 4‰, stop the convection of water, and maintain the reduced salinity overnight, and turn on the convection of water the next day to allow the adult snails to continue laying eggs during the spawning period.

2. The method for artificial domestication, ripening and induced spawning of Epipremnum aquatica according to claim 1, characterized in that: The mixed algae described in S2 include Chaetoceros, Platyhelminthes, Chrysophytes, Diatoms, and Cyclotella.

3. The method for artificial domestication, ripening and induced spawning of Epipremnum aquatica according to claim 2, characterized in that: When S2 is cultured in flowing water, the water inlet flow rate is 3-10L / min.

4. The method for artificial domestication, ripening and induced spawning of Epipremnum aquatica according to claim 2, characterized in that: In step S4, the nutrition fortification is to put large algae such as Undaria pinnatifida and Enteromorpha into the culture pond, and the attachment base for the adult snails to lay eggs is Gnaphalium sphaerocephalum and Abalone plate.

5. A method for collecting egg sacs of Phylum fasciatum, characterized in that: The fine sand, the attachment base for laying eggs by adult snails, and the cylindrical and hemp rope-shaped adhesions on the bottom of the pond in step S4 of the method described in any one of claims 1 to 4 are collected together and placed on a basket with an 80-mesh screen in advance to obtain the egg bag of the snail.

6. Use of the method according to any one of claims 1 to 4, or the method for collecting egg sacs of P. truncatula according to claim 5, in the artificial cultivation of P. truncatula.

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