Sea urchin is a relatively common type of invertebrate in the ocean. Its shell has many moving spines and is shaped like a hedgehog, so it is called "sea locust." Sea urchin is an economic marine organism with high food value, medicinal value, and research value. The gonads of some species are extremely delicious and nutritious. Due to the high content of methionine in the protein, the umami taste is unique, and it is considered to be a delicious seafood in many coastal countries or regions such as Japan, China, the Malay Peninsula, Europe and the Mediterranean Sea and South America. Especially in Japan, the sea urchin's gonads and their processed products are regarded as one of the most valuable and delicious high-end seafood products. The market price is very high and the consumption is also very large. Although Japan has nearly 20,000 tons of production each year, Still can not meet the needs of the consumer market, but also import thousands of tons.
Because sea urchin has broad application prospects and good economic value, its research and development has been increasingly valued by some fishery economically developed countries. Today, Japan's sea urchin seed production and resource reproduction has become one of the important industries for its “cultivation fisheryâ€. The number of research and production units engaged in the cultivation and production of sea urchin seedlings in the country has reached as many as several hundred, and the seedling year The amount of discharge can reach more than 30 million pieces in Hokkaido alone. Affected by the international market, the export price of sea urchins in China has increased by nearly 10 times in 10 years, which has led to an increase in its collection volume and an ever-decreasing amount of resources. Since the introduction of E. japonicus, the artificial breeding and aquaculture of sea urchin has developed rapidly. Now it has become a new industry in the aquaculture of northern China’s coastal areas. With the further development of sea urchin breeding and aquaculture, sea urchin will surely make new and greater contributions to people's production and life. The newspaper will publish sea urchin culture technology in stages from this issue in order to draw lessons from readers.
First, sea urchin nursery facilities and equipment
The artificial breeding of sea urchin refers to the process of obtaining hen-bearing sea urchin seedlings that can be used for breeding by artificially promoting and inducing production of fertilized eggs under artificial conditions, through incubation, selection, breeding of planktonic larvae, and cultivation of juvenile sea urchins. The entire artificial breeding process of sea urchin consists of two main parts: planktonic larval rearing and juvenile sea urchin cultivation.
At present, there are few special sea urchin nursery rooms in the country. The artificial breeding of sea urchins mostly uses the cultivation facilities and water treatment systems of ordinary shellfish nursery or nursery. The use of existing shellfish nursery rooms to carry out artificial sea urchin seedlings, especially the use of shellfish seedlings off-season for sea urchin artificial seedlings, for the development of our country's high quality seafood seedling production, increase the utilization index of the existing nursery facilities, increase the company's economy The benefits are extremely beneficial. The nursery room for sea urchin should have the following basic conditions.
1. Water supply system for nursery
The sea urchin water treatment system is similar to the shellfish seedling water treatment system, and mainly includes an intake pipe system, a water pump, a sedimentation tank, a water filtration system, and a drainage channel. The selection of influent waters is an important aspect of ensuring water quality conditions. The drain should be far away from the inlet and below the tide to prevent self contamination.
2. Floating larval rearing pond
The planktonic larvae used for cultivating sea urchins are more convenient and practical for the operation and management of a rectangular nursery pond with a depth of 1 m to 1.5 m and a volume of ten to several tens of cubic meters. At present, domestic large-scale or medium-sized shellfish nursery ponds or nursery sinks can also be used.
3. Juvenile sea urchin cultivation pond
For the cultivation of juvenile sea urchins, the elongated shallow pool is more convenient for operation and management. At present, most of the domestic and foreign juvenile sea urchin cultivation stages use long strip cultivation ponds (or cultivating sinks) with the same specifications as the Baoyu seedling ponds. In China, there are roughly two types of seedling nursery ponds: single-row breeding ponds and double-row breeding ponds, of which the single-row breeding ponds are 1.3 meters wide, 0.5 meters to 0.7 meters deep, and most are 3 meters to 10 meters in length (or Longer), leaving channels on both sides of each pool, this type of pool operation management is more convenient; dual-row cultivation pond pool width of 0.9 meters, depth and length are basically similar to the previous species, each two pools side by side into a group, each There are channels on both sides of the pool (ie, there are channels on each side of the pool). Although the operation and management of this type of cultivation pond is not as convenient as the former one, the effective utilization of the building area of ​​the nursery room is better than The former pool is slightly higher.
Some foreign countries have built sea urchin nursery ponds with double bottoms, with a spacing of 10 cm to 20 cm between the two floors. Among them, the upper floor is sieve type, and there is a layer of small gravel with a thickness of about 5 cm to 10 cm. The pool is easy to change water, and the water exchange is good. Moreover, the gravel at the bottom of the pool can also be used as an attachment base for some sea urchin planktonic larvae. It not only increases the cultivation area, but also has better cultivation effect than the general cultivation pond.
In order to make full use of the nursery room construction area, a three-dimensional juvenile sea urchin cultivation pond can be constructed. Such cultivation ponds are generally small, with a length of no more than 2 meters, a width of generally less than 0.7 meters, and a height of 0.3 meters to 0.4 meters. Between the two pools are generally more than 0.2 meters apart. The number of layers is generally determined based on the water supply conditions, the height and spacing of the pool, and whether it is beneficial to the operation, and is generally 2 to 3 floors. If the first pool is a ground tank, then the layer can also be added to a layer of 4 to 5 layers. Some nursery workshops have built steps on both sides of the aisle to facilitate feeding and clearing. In addition to the effective use of the building area of ​​the cultivation room, the three-dimensional cultivation pool has the advantage of mutual shading, which is very suitable for the cultivation of juvenile sea urchins. There is a water pipe between the two floors so that the upper water overflows to the lower floor. When the water flows down to the lower pool, it can increase or decrease oxygen.
4. Level 1 bait species preservation room, bait cultivation room and bait culture pool
The first-grade bait species preservation room requires indoor lighting, heat preservation, and ventilation conditions. The interior is equipped with a number of conical flasks used for bait cultivation, two- or three-layer brackets, and filtration and disinfection equipment. The bait culture room generally uses a glass fiber reinforced plastic roof with good transparency, and is equipped with a light curtain that can be dimmed. The bait culture pool in the bait room is divided into two kinds of secondary bait culture ponds and tertiary bait culture ponds, and two-level bait culture ponds. It is better to use a small concrete tank or sink with a depth of 0.4 to 0.6 meters and a volume of 0.5 to 1 cubic meter. A three-tiered bait culture tank uses a medium to small pond with a depth of 0.5 to 0.8 meters and a volume of 3 to 5 cubic meters. it is good. In order to enhance the light required for the growth of the algae under the bait, the inner wall of the bait pool is preferably coated with a white waterproof coating, and the bait-feeding chamber and the bait-cultivation pool of the shellfish nursery room in our country basically meet the above requirements.
5. Benthic diatom cultivation facilities
After the juvenile sea urchin metamorphosis, from planktonic life to benthic life, bait from planktonic algae to benthic diatoms. Benthic diatom culture containers commonly used glass jar (for algae species culture), aquarium (for relay culture) and cement pool (built in indoor or outdoor), pool bottom area of ​​about 1 square meters, about 30 cm high ~ 40 cm, the inner wall of the pool is best covered with white tiles. The benthic diatom culture ponds of the bounty seedlings can also be utilized, and the third-class bait ponds of the shellfish nursery can also be utilized. The attachment base of benthic diatoms is generally used as a corrugated board for seedlings. Attached piece holders generally use a "head" type plastic frame. The corrugated board can be placed on the attachment frame.
The benthic diatom algae are generally collected from the local sea area. The benthic diatoms are collected from a variety of diatoms. Several commonly used benthic diatoms are: Navicula, Algae, Algae, Moon-shaped algae, Oval-like algae. The more convenient collection methods are:
(1) Hanging attachments in the sea Under floating rafts in the sea, various types of attachment bases (such as clam shells, plastic plates, glass slides, and plastic sheets) are hung, and the hanging depth is about 0.5 meters. After two or three days, they will be attached. The debris on the base is rinsed off, and the attached benthic diatoms are scrubbed and collected as algae.
(2) Scraping and sanding Near the middle tide line of the beach, the natural breeding benthic diatoms form yellow-green or yellow-brown dense algae on the surface of the beach. At the lowest tide, surface fine sand with dense algal blooms can be scraped and put into plastic buckets. Clean seawater can be added to stir and remove debris. After a short time, the sediments will sink and the upper liquid will be dark brown, and then go through 20 mesh. Sieve filtration, you can get a large concentration of benthic diatom algae. When collecting benthic diatoms, you can also use a clean white towel to pick up benthic diatoms from the surface of the beach, and then wash the diatoms on the towels into plastic buckets.
(3) Scrub the algae surface of large algae growing on the surface of the seaweed or the bottom wall of the water storage container in the sea area, at the bottom and the four sides of the storage tank, the aquarium of the water storage tank, above the seaweed nursery pool and its harvester There are benthic diatoms attached. These benthic diatoms are scrubbed and collected as algae.
Before inoculation, first the culture container and the attachment device (with corrugated plate attached) must be cleaned and disinfected. The attachment device should be placed in the culture container and filled with sterile seawater. Disinfected seawater generally treats seawater with more than 1/10,000 to 10,000 times of bleaching powder or 1/1000th of a thousandth of bleaching water for more than 12 hours, and needs to be neutralized with one thousandth of sodium thiosulfate before use to avoid inhibition. Benthic diatoms grow. At the time of inoculation, the corrugated plate was inserted into the frame so that the sterile seawater just submerged the entire frame. The collected benthic diatom seed liquid was filtered once and twice with a 200-mesh sieve and poured into the culture tank. Stir the seawater so that the algae is evenly distributed in the water. At rest for a day, benthic diatoms will adhere to the upper side of the corrugated plate (attached on one side). Rinse the corrugated plate gently with water. When the diatoms on the corrugated plate do not come off, change the water in the whole pond, add fresh seawater and fertilize, and start the cultivation. After 2 days to 3 days of culture, the attachment device can be turned over, and the corrugated plate can be inoculated again to obtain two-sided benthic diatoms.
In still water cultivation of benthic diatoms, fresh seawater needs to be replaced and fertilized every two or three days. When the water is changed, the dirt on the bottom of the pool must be washed away, and the enemy mosquitoes such as mosquito larvae and belly hair protozoa should be washed away. The enemy creatures on the corrugated board should also be gently washed away. In the hot season, the number of water changes should be increased, if necessary, change the water once or twice a day. Fertilize immediately after changing water. With conditions permitting, benthic diatoms can be cultivated using recycled or flowing water, and ideal results can be obtained. The light intensity in benthic diatom culture is an important factor. Avoid exposure to direct light at noon, make use of strong diffuse light as much as possible, and use artificial light to fill light in rainy weather. The outdoor pool requires an empty roof and skylight for dimming. Strictly avoid direct exposure to direct light. Benthic diatoms require less light, about 2000 lx. The common enemy organism in the cultivation of benthic diatoms is the copepods, which can be controlled by 0.210-6 to 0.310-6 trichlorfon. In the cultivation of benthic diatoms, it is necessary to observe the pond daily, and perform regular microscopic examination to grasp the growth and reproduction of algae.
During the cultivation of benthic diatoms, seawater is frequently replaced and nutrients are constantly added. The seedling plate is used for collecting attached metamorphosis juvenile sea urchins, and can also be used as an attachment substrate for the cultivation of juvenile sea urchins, and for providing algae bait for attaching post-metamorphic seedlings, and the frame is mainly used for assembling the seedling-picking plate to make it more convenient to operate. management. At present, most sea urchin nursery seedlings use the same pickling seedlings and the framework of the seedlings, that is, the pickling seedlings are non-toxic transparent polyvinyl chloride (PVC) material corrugated sheets, which are generally 40 cm in length and 33 in width. Centimeter, thickness 0.5 mm to 0.8 mm, corrugated wave height 1 cm to 1.5 cm. There are basket-type and folding-type frames for assembling seedling collection boards. Each frame can be assembled with 20 seedling picking boards. Among them, the folding frame is not easy to pull out either horizontally or vertically, and picking seedlings is not easy to pick out. The spacing is larger and the plates do not overlap easily, which is more suitable for sea urchin nursery.
6. Cages and attachment plates
It is used to contain and cultivate peeled young sea urchins. The cages are sewn with plastic gauze and the upper side is open. The specifications of the cages are generally 0.3m to 0.4m deep, and the length and width are about 0.8m to 1.5m. They should be flexibly controlled according to the size of nursery ponds to facilitate the operation and management. in principle. The aperture of the gauze is 1 mm to 5 mm, which should be selected according to the sea urchin specifications cultivated. The pore size should not be too small, otherwise the water permeability is poor, which affects the cultivation effect. The cage needs periodic exposure and cleaning to keep it clean. If there are conditions, the aperture of the cage should be replaced with the size of the sea urchin in order to maintain good water permeability, and the feces of the sea urchin is also easily dropped, thereby keeping the cage clean. When artificial breeding with bait is used for cultivation, the bottom of the cage needs to put 1 to 2 black corrugated plates with holes as the attachment base of the juvenile sea urchins, and they also have the role of accepting bait. The corrugated board is non-toxic black polyvinyl chloride (PVC) or glass reinforced plastic material, and the specification is generally 50 cm to 80 cm in length, 30 cm to 70 cm in width, 0.8 mm to 1.5 mm in thickness, and the corrugated wave height is 3 cm to 5 cm. There are holes in the corrugated crests (or sides) that serve as passageways for the activity of juvenile sea urchins. The size of the openings is about 2 cm to 4 cm, and the distance between holes is about 20 cm.
Because sea urchin has broad application prospects and good economic value, its research and development has been increasingly valued by some fishery economically developed countries. Today, Japan's sea urchin seed production and resource reproduction has become one of the important industries for its “cultivation fisheryâ€. The number of research and production units engaged in the cultivation and production of sea urchin seedlings in the country has reached as many as several hundred, and the seedling year The amount of discharge can reach more than 30 million pieces in Hokkaido alone. Affected by the international market, the export price of sea urchins in China has increased by nearly 10 times in 10 years, which has led to an increase in its collection volume and an ever-decreasing amount of resources. Since the introduction of E. japonicus, the artificial breeding and aquaculture of sea urchin has developed rapidly. Now it has become a new industry in the aquaculture of northern China’s coastal areas. With the further development of sea urchin breeding and aquaculture, sea urchin will surely make new and greater contributions to people's production and life. The newspaper will publish sea urchin culture technology in stages from this issue in order to draw lessons from readers.
First, sea urchin nursery facilities and equipment
The artificial breeding of sea urchin refers to the process of obtaining hen-bearing sea urchin seedlings that can be used for breeding by artificially promoting and inducing production of fertilized eggs under artificial conditions, through incubation, selection, breeding of planktonic larvae, and cultivation of juvenile sea urchins. The entire artificial breeding process of sea urchin consists of two main parts: planktonic larval rearing and juvenile sea urchin cultivation.
At present, there are few special sea urchin nursery rooms in the country. The artificial breeding of sea urchins mostly uses the cultivation facilities and water treatment systems of ordinary shellfish nursery or nursery. The use of existing shellfish nursery rooms to carry out artificial sea urchin seedlings, especially the use of shellfish seedlings off-season for sea urchin artificial seedlings, for the development of our country's high quality seafood seedling production, increase the utilization index of the existing nursery facilities, increase the company's economy The benefits are extremely beneficial. The nursery room for sea urchin should have the following basic conditions.
1. Water supply system for nursery
The sea urchin water treatment system is similar to the shellfish seedling water treatment system, and mainly includes an intake pipe system, a water pump, a sedimentation tank, a water filtration system, and a drainage channel. The selection of influent waters is an important aspect of ensuring water quality conditions. The drain should be far away from the inlet and below the tide to prevent self contamination.
2. Floating larval rearing pond
The planktonic larvae used for cultivating sea urchins are more convenient and practical for the operation and management of a rectangular nursery pond with a depth of 1 m to 1.5 m and a volume of ten to several tens of cubic meters. At present, domestic large-scale or medium-sized shellfish nursery ponds or nursery sinks can also be used.
3. Juvenile sea urchin cultivation pond
For the cultivation of juvenile sea urchins, the elongated shallow pool is more convenient for operation and management. At present, most of the domestic and foreign juvenile sea urchin cultivation stages use long strip cultivation ponds (or cultivating sinks) with the same specifications as the Baoyu seedling ponds. In China, there are roughly two types of seedling nursery ponds: single-row breeding ponds and double-row breeding ponds, of which the single-row breeding ponds are 1.3 meters wide, 0.5 meters to 0.7 meters deep, and most are 3 meters to 10 meters in length (or Longer), leaving channels on both sides of each pool, this type of pool operation management is more convenient; dual-row cultivation pond pool width of 0.9 meters, depth and length are basically similar to the previous species, each two pools side by side into a group, each There are channels on both sides of the pool (ie, there are channels on each side of the pool). Although the operation and management of this type of cultivation pond is not as convenient as the former one, the effective utilization of the building area of ​​the nursery room is better than The former pool is slightly higher.
Some foreign countries have built sea urchin nursery ponds with double bottoms, with a spacing of 10 cm to 20 cm between the two floors. Among them, the upper floor is sieve type, and there is a layer of small gravel with a thickness of about 5 cm to 10 cm. The pool is easy to change water, and the water exchange is good. Moreover, the gravel at the bottom of the pool can also be used as an attachment base for some sea urchin planktonic larvae. It not only increases the cultivation area, but also has better cultivation effect than the general cultivation pond.
In order to make full use of the nursery room construction area, a three-dimensional juvenile sea urchin cultivation pond can be constructed. Such cultivation ponds are generally small, with a length of no more than 2 meters, a width of generally less than 0.7 meters, and a height of 0.3 meters to 0.4 meters. Between the two pools are generally more than 0.2 meters apart. The number of layers is generally determined based on the water supply conditions, the height and spacing of the pool, and whether it is beneficial to the operation, and is generally 2 to 3 floors. If the first pool is a ground tank, then the layer can also be added to a layer of 4 to 5 layers. Some nursery workshops have built steps on both sides of the aisle to facilitate feeding and clearing. In addition to the effective use of the building area of ​​the cultivation room, the three-dimensional cultivation pool has the advantage of mutual shading, which is very suitable for the cultivation of juvenile sea urchins. There is a water pipe between the two floors so that the upper water overflows to the lower floor. When the water flows down to the lower pool, it can increase or decrease oxygen.
4. Level 1 bait species preservation room, bait cultivation room and bait culture pool
The first-grade bait species preservation room requires indoor lighting, heat preservation, and ventilation conditions. The interior is equipped with a number of conical flasks used for bait cultivation, two- or three-layer brackets, and filtration and disinfection equipment. The bait culture room generally uses a glass fiber reinforced plastic roof with good transparency, and is equipped with a light curtain that can be dimmed. The bait culture pool in the bait room is divided into two kinds of secondary bait culture ponds and tertiary bait culture ponds, and two-level bait culture ponds. It is better to use a small concrete tank or sink with a depth of 0.4 to 0.6 meters and a volume of 0.5 to 1 cubic meter. A three-tiered bait culture tank uses a medium to small pond with a depth of 0.5 to 0.8 meters and a volume of 3 to 5 cubic meters. it is good. In order to enhance the light required for the growth of the algae under the bait, the inner wall of the bait pool is preferably coated with a white waterproof coating, and the bait-feeding chamber and the bait-cultivation pool of the shellfish nursery room in our country basically meet the above requirements.
5. Benthic diatom cultivation facilities
After the juvenile sea urchin metamorphosis, from planktonic life to benthic life, bait from planktonic algae to benthic diatoms. Benthic diatom culture containers commonly used glass jar (for algae species culture), aquarium (for relay culture) and cement pool (built in indoor or outdoor), pool bottom area of ​​about 1 square meters, about 30 cm high ~ 40 cm, the inner wall of the pool is best covered with white tiles. The benthic diatom culture ponds of the bounty seedlings can also be utilized, and the third-class bait ponds of the shellfish nursery can also be utilized. The attachment base of benthic diatoms is generally used as a corrugated board for seedlings. Attached piece holders generally use a "head" type plastic frame. The corrugated board can be placed on the attachment frame.
The benthic diatom algae are generally collected from the local sea area. The benthic diatoms are collected from a variety of diatoms. Several commonly used benthic diatoms are: Navicula, Algae, Algae, Moon-shaped algae, Oval-like algae. The more convenient collection methods are:
(1) Hanging attachments in the sea Under floating rafts in the sea, various types of attachment bases (such as clam shells, plastic plates, glass slides, and plastic sheets) are hung, and the hanging depth is about 0.5 meters. After two or three days, they will be attached. The debris on the base is rinsed off, and the attached benthic diatoms are scrubbed and collected as algae.
(2) Scraping and sanding Near the middle tide line of the beach, the natural breeding benthic diatoms form yellow-green or yellow-brown dense algae on the surface of the beach. At the lowest tide, surface fine sand with dense algal blooms can be scraped and put into plastic buckets. Clean seawater can be added to stir and remove debris. After a short time, the sediments will sink and the upper liquid will be dark brown, and then go through 20 mesh. Sieve filtration, you can get a large concentration of benthic diatom algae. When collecting benthic diatoms, you can also use a clean white towel to pick up benthic diatoms from the surface of the beach, and then wash the diatoms on the towels into plastic buckets.
(3) Scrub the algae surface of large algae growing on the surface of the seaweed or the bottom wall of the water storage container in the sea area, at the bottom and the four sides of the storage tank, the aquarium of the water storage tank, above the seaweed nursery pool and its harvester There are benthic diatoms attached. These benthic diatoms are scrubbed and collected as algae.
Before inoculation, first the culture container and the attachment device (with corrugated plate attached) must be cleaned and disinfected. The attachment device should be placed in the culture container and filled with sterile seawater. Disinfected seawater generally treats seawater with more than 1/10,000 to 10,000 times of bleaching powder or 1/1000th of a thousandth of bleaching water for more than 12 hours, and needs to be neutralized with one thousandth of sodium thiosulfate before use to avoid inhibition. Benthic diatoms grow. At the time of inoculation, the corrugated plate was inserted into the frame so that the sterile seawater just submerged the entire frame. The collected benthic diatom seed liquid was filtered once and twice with a 200-mesh sieve and poured into the culture tank. Stir the seawater so that the algae is evenly distributed in the water. At rest for a day, benthic diatoms will adhere to the upper side of the corrugated plate (attached on one side). Rinse the corrugated plate gently with water. When the diatoms on the corrugated plate do not come off, change the water in the whole pond, add fresh seawater and fertilize, and start the cultivation. After 2 days to 3 days of culture, the attachment device can be turned over, and the corrugated plate can be inoculated again to obtain two-sided benthic diatoms.
In still water cultivation of benthic diatoms, fresh seawater needs to be replaced and fertilized every two or three days. When the water is changed, the dirt on the bottom of the pool must be washed away, and the enemy mosquitoes such as mosquito larvae and belly hair protozoa should be washed away. The enemy creatures on the corrugated board should also be gently washed away. In the hot season, the number of water changes should be increased, if necessary, change the water once or twice a day. Fertilize immediately after changing water. With conditions permitting, benthic diatoms can be cultivated using recycled or flowing water, and ideal results can be obtained. The light intensity in benthic diatom culture is an important factor. Avoid exposure to direct light at noon, make use of strong diffuse light as much as possible, and use artificial light to fill light in rainy weather. The outdoor pool requires an empty roof and skylight for dimming. Strictly avoid direct exposure to direct light. Benthic diatoms require less light, about 2000 lx. The common enemy organism in the cultivation of benthic diatoms is the copepods, which can be controlled by 0.210-6 to 0.310-6 trichlorfon. In the cultivation of benthic diatoms, it is necessary to observe the pond daily, and perform regular microscopic examination to grasp the growth and reproduction of algae.
During the cultivation of benthic diatoms, seawater is frequently replaced and nutrients are constantly added. The seedling plate is used for collecting attached metamorphosis juvenile sea urchins, and can also be used as an attachment substrate for the cultivation of juvenile sea urchins, and for providing algae bait for attaching post-metamorphic seedlings, and the frame is mainly used for assembling the seedling-picking plate to make it more convenient to operate. management. At present, most sea urchin nursery seedlings use the same pickling seedlings and the framework of the seedlings, that is, the pickling seedlings are non-toxic transparent polyvinyl chloride (PVC) material corrugated sheets, which are generally 40 cm in length and 33 in width. Centimeter, thickness 0.5 mm to 0.8 mm, corrugated wave height 1 cm to 1.5 cm. There are basket-type and folding-type frames for assembling seedling collection boards. Each frame can be assembled with 20 seedling picking boards. Among them, the folding frame is not easy to pull out either horizontally or vertically, and picking seedlings is not easy to pick out. The spacing is larger and the plates do not overlap easily, which is more suitable for sea urchin nursery.
6. Cages and attachment plates
It is used to contain and cultivate peeled young sea urchins. The cages are sewn with plastic gauze and the upper side is open. The specifications of the cages are generally 0.3m to 0.4m deep, and the length and width are about 0.8m to 1.5m. They should be flexibly controlled according to the size of nursery ponds to facilitate the operation and management. in principle. The aperture of the gauze is 1 mm to 5 mm, which should be selected according to the sea urchin specifications cultivated. The pore size should not be too small, otherwise the water permeability is poor, which affects the cultivation effect. The cage needs periodic exposure and cleaning to keep it clean. If there are conditions, the aperture of the cage should be replaced with the size of the sea urchin in order to maintain good water permeability, and the feces of the sea urchin is also easily dropped, thereby keeping the cage clean. When artificial breeding with bait is used for cultivation, the bottom of the cage needs to put 1 to 2 black corrugated plates with holes as the attachment base of the juvenile sea urchins, and they also have the role of accepting bait. The corrugated board is non-toxic black polyvinyl chloride (PVC) or glass reinforced plastic material, and the specification is generally 50 cm to 80 cm in length, 30 cm to 70 cm in width, 0.8 mm to 1.5 mm in thickness, and the corrugated wave height is 3 cm to 5 cm. There are holes in the corrugated crests (or sides) that serve as passageways for the activity of juvenile sea urchins. The size of the openings is about 2 cm to 4 cm, and the distance between holes is about 20 cm.
Specifications
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