In other areas of abalone cultivation in China and the world, Bao disease has often occurred with the continuous expansion of breeding scale and the prolongation of farming time, and the speed of disease is extremely fast and serious. In China, after the artificial breeding of abalone began in the mid-1980s, the diseases of abalone began to appear in the early 1990s. When the damage is severe, most units fail to grow and grow, resulting in great economic losses. The cause of Bao's disease is complicated, and it is influenced by many factors such as marine chemistry, physics, and power. However, many of the pro-Bao used in artificial breeding of abalone have been collected from local aquaculture areas for many years. Continuous mating has degraded the germplasm of abalone, resulting in abrupt growth of abalone and resistance to decline. The influence of academic factors is also important. In order to fundamentally stop the occurrence of Bao's disease, the experiment and research should also be started from the aspect of Bao's germplasm improvement. In addition, the techniques used for the cultivation of short-term benthic diatom bait have also been further reformed in the artificial breeding of abalone. Using the method of turning plates, the time of feeding benthic diatoms by the young crabs was extended. In order to promote the growth of juvenile abalone, it should be possible to bred large-scale, high-quality seedlings. In order to solve the problem of disease in abalone breeding and increase the growth rate of abalone in 1997, we adopted the hybrid technology between abalone and abalone and abalone and abalone. The use of this technology has significantly enhanced the stress tolerance of the young crabs, greatly improved the survival rate of the young crabs, and brought the seedling volume per unit area to 5,000/m2. At the same time, the growth rate has also been improved. The average shell length of young hens who hatched was more than 70% of the total number above 1.5 cm. This technology was used to reform the seedling process and the new process was named "RHD." First, materials and methods 1. Material nursery pond: specification is 8m long and 0.85m deep and 0.6m, with 738 pools and a total area of ​​5018m2. Transparent corrugated board: Specifications 40cm33cm. The dosage is 80 pieces/m2, sharing about 400,000 pieces. Water supply and gas supply capacity: The water supply capacity is 1740m3/h. The gas supply capacity is 65m3/h. Pro-Bao: 270 Haliotis discus Reeves from Japan; 980 Haliotis discus hannai from Dalian, China. 2. Method Breeding of the abalone: ​​In December 1996, the pro-baptism of the pro-blossom was started. The breeding temperature was 20°C. The bait was fresh Lamina japanica Aresch or Undaria pinntifida (Harv).Sur. Feeding to April 20, the effective accumulation temperature reached 1100°Cday; Haliotis discus hannai began protosococci feeding from February 1st, and until April 20, the effective accumulation temperature reached 800°C. The cultivation of benthic diatoms: its species is mainly Navicla sp. Amphora sp. Cocconeis sp. . The benthic diatoms used for collecting seedlings were cultured on March 1. The benthic diatoms used for the cultivation of rotary plates were cultured on April 10th. The nutrient salt was supplemented once a day during the cultivation, and the nutrient application amount was N:P:Si:Fe=10:1:1:0.1 ppm. The benthic diatoms cultured in two batches were each used for breeding after 40 days of propagation. Artificial oxytocin and hatching: Beginning on April 20, a total of 6 induction and stimulation are performed. Insemination is performed in two forms: "97.1": for the hybrid of Haliotis discus hannai and Haliotis discus Reeve: "97.2": selfing for Haliotis discus hannai. After hatching, a total of 110 million larvae were collected from the pool. Picking seedlings: 6 seedlings were used to share 738 nursery ponds with an area of ​​about 5000m2. Of these, 400 nursery ponds were used by 97.1 to collect seedlings; the rest were used by 97.2 to collect seedlings. Rotor plate cultivation: About 40 days after the larvae were attached, the young crabs were transferred to a new corrugated plate with benthic diatoms by peeling and continued cultivation. At the same time, a non-rotating plate was used for the control. Test observations: Results of various pro-bale ovulations under different accumulative temperatures; fertilization rates in each group; comparison of growth rates; comparison of mortality rates; final production results. II. Results 1. Results of spawning under different accumulated temperature conditions The results of spawning under different accumulated temperature conditions are summarized in Table 1. From Table 1, it can be seen that the spawning situation of Baocheng in different regions is different under different accumulated temperature conditions. The accumulated temperature of the discus hovering at about 750°C was almost normal. However, the accumulated temperature required by discus abalone is higher, and the ovulation can only be performed after 1100°C. In addition, from the actual results of artificial infertility, the discus abalone using abduction methods in the past, the discharge process of pro-bitter sperm and eggs is almost normal. The discus abalone is slightly different, and its stimulation threshold is higher than the former. The stimulation thresholds are shown in Table 2. 2. The fertilization rate of each group was found in the incubation test. The 97.1 group was slightly lower in terms of fertilization rate and hatching rate. The fertilization rate is about 85%, while the 97.2 group is above 90%. However, with the increase of the accumulated temperature of the abalone, the fertilization rate and the subsequent hatching rate are also increased. 3. Comparison of growth rate After 50 days from picking the seedlings, 97.1 groups of juvenile abalone were compared in the growth rate under the mode of rotation and non-rotating plate cultivation. The method was to take 2 pools each, and record them as 1# and 2# respectively. , 3 #, 4 #. Among them, the 1# and 2# groups are juvenile abalones that have not been cultivated on the turntable; the 3# and 4# groups are juvenile abalones that have been raised on the turntable. The average shell length at the beginning of the test is shown in Table 3. From Table 3, it can be seen that the length of the shell is almost the same in each group of juvenile abalones after feeding the first diatom board. Afterwards, the 1# and 2# groups of juvenile abalones began to use artificial diets to cultivate; while the 3# and 4# groups continued to feed benthic diatoms after the transfer. After 30 days of cultivation, the lengths of the shells of the young crabs were measured. The results are shown in Table 4. The results in Table 4 show that at different stages of the cultivation method, the growth rate of the young bait varies greatly. The juvenile abalone grown on the turntable is much longer than the unintentional abalone. The results of the determination of growth in each group at 100 days after seedling collection are shown in Table 5. From the results of Table 5, the growth of the shell length of the juvenile abalone cultivated on the turntable is always greater than that of the juvenile abalone cultivated without the turntable. 4. Comparison of mortality rate of juvenile abalone During the whole year of cultivation, the mortality rate of 97.1 group of young hatchery has been very low, showing excellent traits; while the mortality rate of 97.2 group of juvenile abalone is still relatively high. The daily mortality rate of the two groups of young children between July 10 and August 30 is shown in Table 6 below. As can be seen from Table 6, the 97.2 group had a higher daily mortality rate than the 97.1 group. The total mortality rate for the 97.2 group in both months of July and August was 36%; the total mortality for the 97.1 group was only 3.7%. As the Dalian Fisheries Research Institute presided over by the author adopted the RHD new technology and used a modified species of abalone on a large area, the 1997 seedling production achieved a big harvest, and by mid-September, the number of seedlings reached 25 million. . Due to the production process and the use value, the small seedlings less than 7mm in length were discarded at the end of September. Calculated according to the stock amount at the end of September, the total area of ​​seedlings using the RHD new technology is 5000m2. The amount of seedling per unit area is 5000/m2. Under such high yield conditions, it has been history that there are no such large breeds of seed. By November 14th, there were 16.5 million youngsters with a shell length of 1.5cm or more, which accounted for 70%; shell length 1.0-1.4cm was 6.5 million, accounting for 28%; and 1cm or less was only 2%. Due to the excellent characteristics of these seedlings, after the first winter wintering, the juveniles entered the breeding and breeding period in July of the following year, and after one year of breeding, the longest shell grows to a length of 7cm. Its growth rate is increased by 30% compared with the unhybridized species bred by the old process. 3. Discussion 1. Crossing During the hybridization between abalone and Haliotis discus hannai, it was found that the stimulation threshold of abalone was higher than that of abalone. The percentage of plated larvae was slightly lower than that of abalone. The plate rate. In addition, there was no abnormality in the egg fertilization and larval hatching process. In the subsequent cultivation process, the abundance of juvenile abalone was strong, the survival rate was as high as 80%, and the growth rate was also 30% higher. Experiments have proved that hybrids of abalone and abalone are perfect, and the advantages of hybridization are significant, effectively preventing diseases that have occurred in the current breeding process, thereby greatly improving the quality and yield of seedlings. 2. The rotation of the rotating plate through the rotation plate effectively prolongs the feeding time of the benthic abalone by benthic diatoms, so that the individual shells of the young abalone at the time of stripping are as long as 6 to 7 mm, thereby improving the adaptability of artificially-matched bait cultivation, and can be effective. Improve the survival rate of the young fish. In addition, the cultivation of turntables also plays a role in effectively controlling the cultivation density. It is difficult to achieve the uniformity of the collection density in the past using the old techniques for seedling collection and cultivation. Therefore, it is inevitable that there will be excessive local density in the cultivation process, and this part of the hatchery is difficult to grow to ideal specifications. of. The juvenile abalone that has passed the transfer board has a clear and strict density requirement and is easy to grasp. Therefore, the cultivation density is appropriate and uniform, which promotes the growth of the juvenile abalone. 3. About the collection rate of larvae In the process of crossing, we also found that the rate of attachment of the hybrid larvae at the time of picking was slightly lower than that of the self-crossing of the discus abalone. This is a difference from the previous collection. Although this phenomenon does not have a great impact on the entire nursery, it should be taken seriously in future experiments to find out the cause and solve it.