1 Basic Conditions Jiaozhou Bay is a semi-enclosed inner bay with stable flow. There are multiple freshwater injections, and the basic productivity is relatively high. It is particularly suitable for habitat breeding of vermicular diploids feeding on benthic diatoms and organic detritus. Large, meaty and delicious, it is a traditional bulk export product. The development of variegated alfalfa artificial seedling production has unique conditions.
The test site is located in the seawater breeding nursery of Hongdao Town, Chengyang District, Qingdao City, which is adjacent to Jiaozhou Bay.
Seawater enters the sedimentation tank through high tide, and is used as seedling workshop water after being filtered by sand in the high-level pool; the treated seawater samples are examined with few protozoa and all below 10um.
Glass tank for culture tanks, size 3m x 4m x1.2m.
2 Pro-shellfish selection and hatching Pro-sex selection of full-shape, full gonadal development, maturity of Jiaozhou Bay 2 Bay shell production. Dissecting microscopy: The shape of the egg is regular, round or oval, with a diameter of 70-80um. Immediately after the water becomes round; sperm is very active.
In 2002, the water temperature in Jiaozhou Bay was higher than in previous years, and the spawning period was advanced. On April 30th, we selected 25kg of pro-shellfish, cleaned it, dried it for 10 hours, put it in a rectangular plastic tray, put it into a glass jar, stimulated by running water, laid eggs gradually after 9 hours, and spawned for half an hour each time. The egg density was 40-50/ml. During the incubation, increase the oxygenation amount and apply EDTA3 to 5xl0-6.
3Cultivation management
3.1 Culture pool water conditions The water temperature was 22 °C, pH 8.1, dissolved oxygen 7.0 mg / L, salinity 32,22 hours after the transfer of D-shaped larvae, hatching rate of 85%.
At this time, quickly collect the seedlings with a 300-mesh sieve (must use the standard sieve, otherwise, it is easy to miss the larvae) and pour into the prepared pool so as to remove excess sperm and impurities. The density of D-shaped larvae is controlled at 20 to 25 cells/ml.
3.2 Food
The D-shaped larva stage was dominated by small diatoms and Xanthomonas oryzae, and the feeding amount was 25,000-30,000 cells/ml, and was fed 4 times a day.
Shell larvae were fed with forked algae, chaetoceros, and Platymonas subtilis. The single-feeding bait had a density of 30,000-40,000 cells/ml, and mixed feeding was conducted at 40,000-50,000 cells/ml. should.
When the water temperature was 24°C and other conditions were constant, the growth and development occurred after 14 days, the body length was 190 to 230 μm, and metamorphosis and campsite life began.
3.3 Adhesion bases shall be selected for the production of local fine sand, which shall be placed in the bottom of the pool after being disinfected with water and laid with a thickness of 0.5cm.
The bait is mainly composed of Chaetoceros, Platymonas and benthic diatoms transplanted indoors, and the amount of feeding increases with the individual's growth. Feeding 6 times a day.
3.4 daily routine microscopy every day, check larvae gastrointestinal fullness, according to the specific circumstances of timely adjustment of feeding amount; check whether the disease occurs, the appropriate use of antibiotics 3 regularly measured body length every day, make records, compare, from body length growth The situation judges whether the growth is normal. Pour the pool once a week and change the water twice a day.
4 Results The hatching rate of eggs was 85%. The first batch raised 7 billion larvae of D-shaped larvae. Due to the insufficient supply of bait, some of them were transferred to outdoor soil pools for cultivation, and the remaining 2 billion were cultured indoors. From the D-shaped larvae to metamorphosis attachment, 800 million larvae were co-cultured, and the survival rate was 40%; 400 million double-tube larvae were cultivated, and the survival rate was 20%.
5 It is suggested that the seedlings will be cultivated into commodity seedlings from the time they begin to bury and live, and the outdoor cultivation time will be 4 to 5 months. Whether the management is appropriate or not will directly affect the seedling emergence rate, therefore, it is recommended to do the following tasks:
5.1 Laying Sand Layers When the sand content of the bottom of the outdoor culture pool reaches 60% to 80%, it will be beneficial to the buried life of the seedlings.
5.2 Maintain adequate feeds Take measures such as changing seawater, applying compound fertilizers, lowering water levels, increasing light, etc., and multiply basic baits to meet the growth requirements of seedlings.
5.3 Strictly Prevent Enemy Exclusion Beyond strict protection against devastating natural disasters such as typhoons and floods, biological predators such as copepods, canola, silkworms, shrimps and crabs should also receive sufficient attention. Clear the pond thoroughly before releasing the seedlings. After the stocking, prevent the water filter net from being damaged, drain the pool water regularly, and chase to catch predators.
The test site is located in the seawater breeding nursery of Hongdao Town, Chengyang District, Qingdao City, which is adjacent to Jiaozhou Bay.
Seawater enters the sedimentation tank through high tide, and is used as seedling workshop water after being filtered by sand in the high-level pool; the treated seawater samples are examined with few protozoa and all below 10um.
Glass tank for culture tanks, size 3m x 4m x1.2m.
2 Pro-shellfish selection and hatching Pro-sex selection of full-shape, full gonadal development, maturity of Jiaozhou Bay 2 Bay shell production. Dissecting microscopy: The shape of the egg is regular, round or oval, with a diameter of 70-80um. Immediately after the water becomes round; sperm is very active.
In 2002, the water temperature in Jiaozhou Bay was higher than in previous years, and the spawning period was advanced. On April 30th, we selected 25kg of pro-shellfish, cleaned it, dried it for 10 hours, put it in a rectangular plastic tray, put it into a glass jar, stimulated by running water, laid eggs gradually after 9 hours, and spawned for half an hour each time. The egg density was 40-50/ml. During the incubation, increase the oxygenation amount and apply EDTA3 to 5xl0-6.
3Cultivation management
3.1 Culture pool water conditions The water temperature was 22 °C, pH 8.1, dissolved oxygen 7.0 mg / L, salinity 32,22 hours after the transfer of D-shaped larvae, hatching rate of 85%.
At this time, quickly collect the seedlings with a 300-mesh sieve (must use the standard sieve, otherwise, it is easy to miss the larvae) and pour into the prepared pool so as to remove excess sperm and impurities. The density of D-shaped larvae is controlled at 20 to 25 cells/ml.
3.2 Food
The D-shaped larva stage was dominated by small diatoms and Xanthomonas oryzae, and the feeding amount was 25,000-30,000 cells/ml, and was fed 4 times a day.
Shell larvae were fed with forked algae, chaetoceros, and Platymonas subtilis. The single-feeding bait had a density of 30,000-40,000 cells/ml, and mixed feeding was conducted at 40,000-50,000 cells/ml. should.
When the water temperature was 24°C and other conditions were constant, the growth and development occurred after 14 days, the body length was 190 to 230 μm, and metamorphosis and campsite life began.
3.3 Adhesion bases shall be selected for the production of local fine sand, which shall be placed in the bottom of the pool after being disinfected with water and laid with a thickness of 0.5cm.
The bait is mainly composed of Chaetoceros, Platymonas and benthic diatoms transplanted indoors, and the amount of feeding increases with the individual's growth. Feeding 6 times a day.
3.4 daily routine microscopy every day, check larvae gastrointestinal fullness, according to the specific circumstances of timely adjustment of feeding amount; check whether the disease occurs, the appropriate use of antibiotics 3 regularly measured body length every day, make records, compare, from body length growth The situation judges whether the growth is normal. Pour the pool once a week and change the water twice a day.
4 Results The hatching rate of eggs was 85%. The first batch raised 7 billion larvae of D-shaped larvae. Due to the insufficient supply of bait, some of them were transferred to outdoor soil pools for cultivation, and the remaining 2 billion were cultured indoors. From the D-shaped larvae to metamorphosis attachment, 800 million larvae were co-cultured, and the survival rate was 40%; 400 million double-tube larvae were cultivated, and the survival rate was 20%.
5 It is suggested that the seedlings will be cultivated into commodity seedlings from the time they begin to bury and live, and the outdoor cultivation time will be 4 to 5 months. Whether the management is appropriate or not will directly affect the seedling emergence rate, therefore, it is recommended to do the following tasks:
5.1 Laying Sand Layers When the sand content of the bottom of the outdoor culture pool reaches 60% to 80%, it will be beneficial to the buried life of the seedlings.
5.2 Maintain adequate feeds Take measures such as changing seawater, applying compound fertilizers, lowering water levels, increasing light, etc., and multiply basic baits to meet the growth requirements of seedlings.
5.3 Strictly Prevent Enemy Exclusion Beyond strict protection against devastating natural disasters such as typhoons and floods, biological predators such as copepods, canola, silkworms, shrimps and crabs should also receive sufficient attention. Clear the pond thoroughly before releasing the seedlings. After the stocking, prevent the water filter net from being damaged, drain the pool water regularly, and chase to catch predators.