Low salinity blue crab high-yielding aquaculture technology
Natural Puer Tea,Peak Pu Er,Healthy Hour Super Herbal Tea Runming Tea Co., Ltd. , http://www.onlinechinagreentea.com
November 06 19:01:49, 2018
Doizhu District of Zhuhai City is located at the Xijiang Jump Gate and Yamen Estuary, where there is a large amount of fresh water, and the salinity in the sea area is low, between 2 and 13 in. In recent years, Qiang District and nearby farmers have vigorously developed blue crab breeding and achieved greater benefit. Doumen District blue crab breeding mainly in the area of ​​the reclamation area, there are 17715 acres of aquaculture area, in 2002 the production of green crab was 1241 tons, the total output value of 63.72 million yuan. In 2003, there was even greater development. The main points of this breeding technique are summarized as follows. This technique is also suitable for other crab breeding production in low salinity regions. I. Crab Ponds The construction of crab ponds suitable for raising crabs should be 15-25 mu. There is also a pond in Tangzhong, and the entrance and drain gates in Datang are built. The whole pond has a ring-shaped pond, 3 meters wide and 2 meters deep. , Tang Zhong Niu Pier has a "non-"-shaped ditch and the ring Tonggou connected. There are two small ponds in the near entrance of Datanghe: 1 mu and 2 mu (1 mu pond is used to cultivate crab seedlings and seedlings are thick, 2 mu ponds are used for semi-paste crab and cream crab cultivation. Cultivate) Each of the two small ponds will have a water intake and an anti-escape facility. 2. After clearing the pond and destroying the crab pond, the clear pond shall be drained of the “non-shaped†ditch, the bottom of the pond shall be leveled and the bottom of the “non-†character shall be ditched. Each kilogram of quicklime uses 50kg of quicklime to splash in the pond. When entering the water, it is filtered by three layers of 40, 60, and 80 mesh gauze, and water is taken in one time. After 7 days, the body of water is disinfected with “three acres of spirit†or “dibromohydantoinâ€. After another three days, the bio-agents such as “Lee Lido†were used to gradually transfer water, and the salinity in the pond was stable at 4‰-8‰. Third, the crab seedlings should be tested before putting water on the seedlings. Naturally caught crab seedlings should be put into a small pond in 1 mu for raising, and the crabs should be kept for 24 hours. Crabs should be sterilized before entering the pool. The method is to use 50 kg of fresh water, 0.5 kg of sea salt, and 10 g of potent iodine to be mixed into liquid medicine. Put the crabs in batches into the medicine bath for 3-5 seconds, and then put them into the culture tank. The disinfection of crabs is to prevent the crabs of fishing damage or broken limbs from being infected by bacteria or viruses, and to remove ciliates caused by the species of crabs and increase the survival rate. Crabs were incubated for 15 days after being fed. Most of the crabs were cultivated into crabs, which were put into ponds for crab breeding. The breeding density was 3000 birds per mu. IV. Feeding and management 1. Feeding: The food intake of blue crabs increases or decreases with changes in water temperature, water quality, salinity, dissolved oxygen, pH, ammonia, and other environmental conditions. After the tide changes water, the environment is normal and the food intake is increased. Therefore, observations, checks, or adjustments to the amount of feeding should always be made. In the early stage of the crab, the small blue dragonfly (white pheasant) is cast, and the daily amount accounts for 30% of the body weight of the crab, and the small ration fish and the artificial compound account for 10%-12% of the body weight of the crab. In the medium term (medium crab), the amount of the blue fleas is shot. 20% of body weight, small trash fish, and compound materials accounted for 8%-10% of body weight. In the later period (large crabs), Japanese maggots accounted for 7% of body weight, and small trash fish and compound materials accounted for 5% of body weight. The bait should be thrown at the Huantang Gou and the “Non†gully shoal, and should be put evenly to avoid fighting for food and cause disputes. 2, change the water: green crab hi in the fresh water, high oxygen content in the environment, the oxygen consumption in the clam shell is large, especially sensitive to the quality of water quality, if its own pond water is too "old water", "deadwater" "Contaminated water" cannot be shelled, the food intake is greatly reduced, the old one is raised, and the raising is old (becomes old crabs or stone crabs). There are two high tide periods every month. You must master the change of water, and you should pay attention to changing the water every time. The temperature difference or salinity of the old and new water should not be too large. 3. Elimination of harmful factors on a regular basis: Green crabs are kept throughout the year, large catches stay small, and a large amount of excrement is deposited on the bottom of the pond. The pond is highly contaminated, especially when it is difficult to change the water in the dry season, and the harmful substances in the pond exceed the standard and the water quality deteriorates. , easy to develop. Therefore, regularly spread high quality "bottom net" and other sediment modifiers and high concentration of water improver once every 20 days to maintain a good environment, so that the normal growth of blue crabs. 4. The patrol pond: always check the gate, whether the escape prevention facilities are damaged, observe the change of water color, the crab dynamics, the growth of the oyster shell, the bait-feeding status, and the predator or symptom of the attack. V. Prevention and treatment of blue crab disease Green crab culture is susceptible to sudden changes in the physical factors such as climate, water temperature, salinity, and rain, and invasion of protozoa. The common diseases found in the production of the writer are: 1. Absinitis: The disease suddenly becomes higher or lower due to salt difference or temperature difference, salt difference, temperature difference is too large, so that the crab can not stand the sudden changes in the environment and infection, open the head The breastplate inspects the stomach wall, ovary, and testis for destruction and odor. The mortality rate of this disease is very high. Control methods: First of all, the water temperature can not be changed by more than 5 °C, salinity can not exceed 5 ‰; Second, the diseased crabs should be promptly removed, and then treated with drugs. 5 grams of "crabcorn" and 3 grams of garlic were mixed with each kilogram of crab to make the bait and fed for 3-5 consecutive days. In addition, 0.8 grams of "Draconic" and 0.3 grams of potassium permanganate were used per cubic meter of water. , 15 grams of sea salt, mixed with water and sprinkle the whole pond. 2. Hull disease: Due to shallow pond water level, long-term water temperature is high, especially in summer weather, it is easy to get the disease. There is a light yellow, light red, light white spot on the head chest shell, open the head breast check, head breastplate The endometrial wall is separated from the cephalothorax and the shells and membranes are eroded and eroded. The disease is also called the crustacean ulcer disease. The prevention and control method is mainly to constantly change the water temperature and lower the water temperature, and to cast more blue gills and other high calcium-containing shellfish feeds. Kilograms of artificial pellets were mixed with 5 grams of "Kangkangning" and 5 grams of fish were made of cod liver oil bait and fed for 3-5 consecutive days. In addition, 0.3 grams of "Dactylone" and 15 grams of sea salt and water are splashed in every cubic meter of water. 3. Parasitic diseases: Aquaculture water bodies age, and pests such as ciliates reproduce in abundance, parasitize in the silk or abdomen of crabs, absorb nutrients from crabs and destroy capillarity capillaries, making it difficult for crabs to absorb oxygen in the water, resulting in tissue hypoxia. And continue to die. Control methods: When the water can not be changed in the dry season, cast "fixed oxygen" (1 mu 1-2 bags) to improve the water quality, at the same time, 5 grams of "chicocin" per kilogram of crab material, 5 grams of "strong gram 101" system Medicine bait feeding, continuous 2-3 days. Second, 1 gram of "shrimp fibrin net" per cubic meter of water was splashed. 4, muscle necrosis: usually feeding too much, crab excrement deposits, serious self-pollution, delayed clam shell cycle, resulting in shell muscles can not be old dead. Control methods: timely change of water, keep the water clear, live, cool, control the amount of feed and feed fresh feed, in addition, every cubic meter of water with 5 grams of tea seed cake soaked in water for 24 hours, spilled to stimulate the growth of oyster shell. 5. Slow claw disease: Due to the relatively poor environment of cultured water quality, the cycle of the clam shell is prolonged in each period, which is commonly known as keeping old and raising little. Diseased crabs have nervous convulsions. The hair should be slow and slow to crawl. Control methods: Change the water frequently, and feed fresh blue cockroaches. About 20 kg of lime are released per acre every 20 days, followed by 5 g of high-strength "B even water" per kg artificial granules, feeding for 2-3 consecutive days. 6, landing disease: due to malnutrition, pathogens, parasites attack, diseased crabs fled the original water, find a new environment, reduce food intake, and gradually die. Control method: 1 meter deep water per acre with "ashore stop A package" 1 packet of water after Quanchiposa, and then use the pool of water on the shore of the crab; per kilogram of feed with "ashore stop B package" 10 grams, continuous feeding 3-4 days, if the condition is serious, repeat a course of treatment. 7, shivering disease (shaking disease): caused by a virus infection. Poor nutritional quality is a precipitating factor. The diseased crab is unresponsive, slow-acting, the gripping force of the chewing claws is weakened, and the eating and eating are reduced and not eaten; the cocoons are arranged irregularly and are light brown, and a few are even black. Stepping and trembling, ring claws, claws to the ground, abdomen off the ground, and even the crab body upside down. In the later stages of the disease, it is often secondary to infection with Aeromonas hydrophila and Vibrio, causing the disease to worsen, hepatopancreas degeneration, necrosis, pale yellow, and finally pale, there is a large amount of ascites in the carapace, step muscle atrophy, Edema. Sometimes the neoplasia of the cephalothorax (carapace) is also necrotic and shedding, and finally the crab dies due to nervous disorders, dyspnea, and heart failure. A disease that is very serious for crab culture. Treatment method: If the diseased crab has parasites on its surface, it should kill the ectoparasite (fixed ciliate) first. Prevent infection while treating, and can not obtain a good therapeutic effect. Spill out "dibromohydantoin", "San Mu Ling" and other disinfecting drugs. A course of 2-4 days. When taking internal medicines, the medicines that have proven to be effective in practice are selected mainly: for example: "Crab Shaving Corning" (6 ‰-8 ‰ baits) and "Virus San" (6 ‰ baits), usually for 6 days as a course of treatment. Treatment 1-2 courses. The basic disease control of diseased crabs, eating basically normal, you can continue to add "liver and kidney Corning" in the feed to promote rapid and complete recovery and growth of diseased crabs. 8, pests: in the tidal phase of changing the water, said bacteria, miscellaneous shrimp, seafood, yellow feet, etc., are with the water into the crab pond, is the enemy of crabs, so regular 90-100 days in addition to predators Once, with 10 kg of tea seedlings per acre, the water was immersed in water for 24 hours and then sprinkled with water. 6. Harvesting Coastal crabs have been traditionally reared in a round-robin style. Due to the different sizes of crabs, there are large and small crabs. Large-sized crabs are fattened into crabs in 20-30 days, especially males. Too many crabs should be caught in time to stay small. Female crabs that reach the crabs should also be caught and listed. During the whole breeding process, crabs can be caught every day. Crab-cracking methods: 1. Cone-shaped cages are fixed at the central position of the ditch with bamboo sticks. 2, Snake Cage net loading and arresting: In the "non-" word ditch, ring Tanggou evening six fashion catch. 3, arrested: with a large aluminum net "four corners" arrested, put rotten flesh within the trapping effect. 4. Grab: In winter, put shallow water in the pond and fish with crabs. VII. Transportation Due to the drought-resistance of the blue crabs, under normal circumstances, use non-toxic sack cloth to soak the salt water, place it on the bottom of the basket, and then put the finished crabs. Such a layer stacks the baskets, and the basket lids are locked with a net. , Green crabs can still be kept fresh within 48 hours of shipment.