Perinereis aibuhitensis Grub belongs to Annelida, Polychaeta, Erranlia, Nereidae, and Nereis. The body is long worm-shaped, the largest number of links up to more than 230 sections, body length 27cm, body width 1cm, cross-section is round or slightly flat, commonly known as jellyfish or sea grasshopper. This species has important economic significance in marine aquaculture production and marine fisheries, commonly known as "universal bait." At present, coastal areas are investing in the development of tidal flatworms for the breeding of silkworms, in urgent need of seedlings, so seed production has greater potential for development.
1 The basic equipment can use existing shrimp and crab nursery equipment to ensure basic conditions such as water supply and drainage, bait feed, temperature control, seawater sedimentation and filtration.
2 The source of the silkworm parent and male and female identify the parent of the desert silkworm from two sources: one is to collect the mature silkworm body of the mature silkworm swimming in the seashore tidal flat. Generally, it is natural to appear in the seaside tidal flat or salt field in the early and mid-month of the lunar calendar in July and August. Multiple sexually mature male and female cocoon bodies; second, artificially cultured silkworms that are fully grown and will be transformed into coccus jujuba bodies, making them become coccus bodies. When the double-toothed cocoon turns into a cocoon body, the body constantly shakes and oscillates. The body length gradually shortens to 1/3 to 1/4 of the length of the original body. The width is widened and flattened, and the body color is bright green. The feet are white, widening and flattening in the longitudinal direction, producing flat, paddle-like bristles that tend to be suitable for rapid swimming in seawater. The abdomen is pale and the body is divided into three parts: the front area (åŒåŒ area), the middle area (swimming area), and the back area (tail area). In male and male cobweb swimming areas, 8 to 10 mastoids are located on the dorsal foot, and the backs of females are smooth without mastoids.
3 Artificial insemination and incubation of fertilized eggs
3.1 Artificial insemination Put the male and female cocoon body at a ratio of 2 to 3:1, add appropriate amount of sterile seawater to induce spawning and ejaculation, and after complete discharge, wash eggs with seawater several times to wash away excess Semen, otherwise it will affect the hatching rate.
3.2 Incubation density of fertilized eggs is controlled at 0.5 to 10,000/L, water temperature is 26 to 28°C, pH is 7.8 to 8.6, salinity is 25 to 28, and air volume is maintained. At 1.5% of the total body of water per minute. Pay attention to the control of water quality, there can be no protozoa; In addition, because the fertilized egg of the double-toothed Bombyx mori is a sink egg, it is easy to sink, must pay attention to often stir the bottom, do not sink, in order to avoid oxygen deficiency.
3.3 larvae bred in the water temperature of 26 °C ~ 28 °C under the circumstances of about 2 days hatch hatchlings can be three rigid sections of larvae, larval body cilia suitable for swimming. At this point, the larvae still use the body's egg butter ball as a nutrient, no feeding of baits, and two days later they enter the period of four-day-old larvae. The digestive tract begins to open and the egg butter ball disappears. The bait is mainly composed of yeast and Dunaliella, Platymonas, and small diatoms, 1 g/m3 of yeast, and 150,000 to 200,000/liter of monocytic algae, which are fed once every morning and afternoon. When reaching the 5th section, the spirulina powder can be properly added 0.5g/m3, and then added according to the juvenile feeding conditions. (5) After larvae have been severed on the larvae, the cilia of the larvae are gradually reduced and no longer swim, and they begin to enter the benthic habitat. They need to put in fine sand with a diameter of about 0.1 mm as the attachment base. The fine sand should not be too thick, 3 to 5 mm. can.
4 daily management
4.1 Change water and inflate with 100 mesh sieve to change the water, change the water in the previous period 1/3 to 1/2 every day, when the film is out, it needs to increase the amount of water exchange; later, due to the increase of feeding, the accumulation of the residual bait will be corrupted. Water quality, water change can be increased to 2/3 each time, change the water twice a day. 8 After the larvae of the larvae, the 80-mesh sieve can be used to change the water, otherwise the excrement cannot be replaced. When the larvae are out of the membrane, the aeration rate still needs to be maintained at a rate of 1.5% per minute, and the amount of aeration can be appropriately reduced when the larvae are dive.
4.2 The success or failure of disease control and nursery is closely related to the prevention and treatment of diseases. If the water treatment is not thorough, protozoa will take advantage of the deficiency, and the large number of breeding will cause the failure of the nursery. The damage is mainly in the early stage of nursery. The protozoa not only eats fertilized eggs, but even eats embryos inside the egg membrane. Some of them even parasitize the surface of the larvae and produce large amounts of toxins, which endanger the fertilized eggs and larvae. In order to prevent the harm of protozoa, the following measures can be taken: firstly, sterilize the brood body; secondly, sterilize the fertilized egg, wash the egg, and use sand-filtered seawater; and, once the protozoa are found, one can change a lot of water and eliminate water. Organic matter, cleaning up protozoa and inhibiting its reproduction; it is also possible to splash 20-30 ml/m3 of formaldehyde and 0.5 g/m3 of potassium permanganate or oxytetracycline 1 g/m3 in the water, changing the water after 12 hours.
4.3 Salinity The appropriate salinity for seedling control is between 25 ‰ and 28 ‰. It is important to pay attention to the changes of salinity when changing the water. In particular, it is necessary to pay attention not to drastically change the salinity in the early stage. After entering the Ganglionic larvae, the larvae's ability to adapt to changes in salinity has increased.
4.4 Control of larval density Under the condition of ensuring good inflation, the hatching density of fertilized eggs can be reduced to 0.1 million pieces/l in the case of larvae of 0.5 to 10,000 grains/1,3. 4 When the larvae were barefoot, they were reduced to 500,000/m3; after reaching 5 larvae, because of the beginning of benthic habitat, the appropriate density was 10,000 to 20,000/m2; with the increase in the number of gangs, the larvae When growing up, the density should be further reduced. Otherwise, due to competition for space and bait, the larvae are significantly increased in size, resulting in death and affecting the emergence rate.
4.5 Inspection of seedlings The inspection of seedlings can promptly detect problems and deal with them in time, which is an important part of seedling production. Fertilized eggs during the incubation period can be examined to understand the fertility rate, embryonic development, protozoa and other hazards. The early oil globules of normal fertilized eggs are clear and full, and there is a sense of flow within the embryo; when reaching the larval stage of the membrane, the embryos should be flexible and vigorous in the membrane. In the third rigid section of the Shenzu larvae, the vigor of the larvae and the bristles on the cheeks are observed to be detached. When the larvae are squatted on the four rigid sections, attention should be paid to the development of the digestive tract in order to feed the palatability food in time and pay attention to it. Ingestion, whether the stomach is full, whether the intestinal motility is normal, and how the feces are; when the larvae develop to five rigid sections, the body's swimming cilia have basically disappeared and the larvae have turned to benthic habitat. Base, while paying attention to larval density.
1 The basic equipment can use existing shrimp and crab nursery equipment to ensure basic conditions such as water supply and drainage, bait feed, temperature control, seawater sedimentation and filtration.
2 The source of the silkworm parent and male and female identify the parent of the desert silkworm from two sources: one is to collect the mature silkworm body of the mature silkworm swimming in the seashore tidal flat. Generally, it is natural to appear in the seaside tidal flat or salt field in the early and mid-month of the lunar calendar in July and August. Multiple sexually mature male and female cocoon bodies; second, artificially cultured silkworms that are fully grown and will be transformed into coccus jujuba bodies, making them become coccus bodies. When the double-toothed cocoon turns into a cocoon body, the body constantly shakes and oscillates. The body length gradually shortens to 1/3 to 1/4 of the length of the original body. The width is widened and flattened, and the body color is bright green. The feet are white, widening and flattening in the longitudinal direction, producing flat, paddle-like bristles that tend to be suitable for rapid swimming in seawater. The abdomen is pale and the body is divided into three parts: the front area (åŒåŒ area), the middle area (swimming area), and the back area (tail area). In male and male cobweb swimming areas, 8 to 10 mastoids are located on the dorsal foot, and the backs of females are smooth without mastoids.
3 Artificial insemination and incubation of fertilized eggs
3.1 Artificial insemination Put the male and female cocoon body at a ratio of 2 to 3:1, add appropriate amount of sterile seawater to induce spawning and ejaculation, and after complete discharge, wash eggs with seawater several times to wash away excess Semen, otherwise it will affect the hatching rate.
3.2 Incubation density of fertilized eggs is controlled at 0.5 to 10,000/L, water temperature is 26 to 28°C, pH is 7.8 to 8.6, salinity is 25 to 28, and air volume is maintained. At 1.5% of the total body of water per minute. Pay attention to the control of water quality, there can be no protozoa; In addition, because the fertilized egg of the double-toothed Bombyx mori is a sink egg, it is easy to sink, must pay attention to often stir the bottom, do not sink, in order to avoid oxygen deficiency.
3.3 larvae bred in the water temperature of 26 °C ~ 28 °C under the circumstances of about 2 days hatch hatchlings can be three rigid sections of larvae, larval body cilia suitable for swimming. At this point, the larvae still use the body's egg butter ball as a nutrient, no feeding of baits, and two days later they enter the period of four-day-old larvae. The digestive tract begins to open and the egg butter ball disappears. The bait is mainly composed of yeast and Dunaliella, Platymonas, and small diatoms, 1 g/m3 of yeast, and 150,000 to 200,000/liter of monocytic algae, which are fed once every morning and afternoon. When reaching the 5th section, the spirulina powder can be properly added 0.5g/m3, and then added according to the juvenile feeding conditions. (5) After larvae have been severed on the larvae, the cilia of the larvae are gradually reduced and no longer swim, and they begin to enter the benthic habitat. They need to put in fine sand with a diameter of about 0.1 mm as the attachment base. The fine sand should not be too thick, 3 to 5 mm. can.
4 daily management
4.1 Change water and inflate with 100 mesh sieve to change the water, change the water in the previous period 1/3 to 1/2 every day, when the film is out, it needs to increase the amount of water exchange; later, due to the increase of feeding, the accumulation of the residual bait will be corrupted. Water quality, water change can be increased to 2/3 each time, change the water twice a day. 8 After the larvae of the larvae, the 80-mesh sieve can be used to change the water, otherwise the excrement cannot be replaced. When the larvae are out of the membrane, the aeration rate still needs to be maintained at a rate of 1.5% per minute, and the amount of aeration can be appropriately reduced when the larvae are dive.
4.2 The success or failure of disease control and nursery is closely related to the prevention and treatment of diseases. If the water treatment is not thorough, protozoa will take advantage of the deficiency, and the large number of breeding will cause the failure of the nursery. The damage is mainly in the early stage of nursery. The protozoa not only eats fertilized eggs, but even eats embryos inside the egg membrane. Some of them even parasitize the surface of the larvae and produce large amounts of toxins, which endanger the fertilized eggs and larvae. In order to prevent the harm of protozoa, the following measures can be taken: firstly, sterilize the brood body; secondly, sterilize the fertilized egg, wash the egg, and use sand-filtered seawater; and, once the protozoa are found, one can change a lot of water and eliminate water. Organic matter, cleaning up protozoa and inhibiting its reproduction; it is also possible to splash 20-30 ml/m3 of formaldehyde and 0.5 g/m3 of potassium permanganate or oxytetracycline 1 g/m3 in the water, changing the water after 12 hours.
4.3 Salinity The appropriate salinity for seedling control is between 25 ‰ and 28 ‰. It is important to pay attention to the changes of salinity when changing the water. In particular, it is necessary to pay attention not to drastically change the salinity in the early stage. After entering the Ganglionic larvae, the larvae's ability to adapt to changes in salinity has increased.
4.4 Control of larval density Under the condition of ensuring good inflation, the hatching density of fertilized eggs can be reduced to 0.1 million pieces/l in the case of larvae of 0.5 to 10,000 grains/1,3. 4 When the larvae were barefoot, they were reduced to 500,000/m3; after reaching 5 larvae, because of the beginning of benthic habitat, the appropriate density was 10,000 to 20,000/m2; with the increase in the number of gangs, the larvae When growing up, the density should be further reduced. Otherwise, due to competition for space and bait, the larvae are significantly increased in size, resulting in death and affecting the emergence rate.
4.5 Inspection of seedlings The inspection of seedlings can promptly detect problems and deal with them in time, which is an important part of seedling production. Fertilized eggs during the incubation period can be examined to understand the fertility rate, embryonic development, protozoa and other hazards. The early oil globules of normal fertilized eggs are clear and full, and there is a sense of flow within the embryo; when reaching the larval stage of the membrane, the embryos should be flexible and vigorous in the membrane. In the third rigid section of the Shenzu larvae, the vigor of the larvae and the bristles on the cheeks are observed to be detached. When the larvae are squatted on the four rigid sections, attention should be paid to the development of the digestive tract in order to feed the palatability food in time and pay attention to it. Ingestion, whether the stomach is full, whether the intestinal motility is normal, and how the feces are; when the larvae develop to five rigid sections, the body's swimming cilia have basically disappeared and the larvae have turned to benthic habitat. Base, while paying attention to larval density.