Nibea miichthioides is a genus of fish, and is a genus of the genus Apocynchus. It is commonly known as é²ˆ é²ˆ and is mainly distributed in the subtropical waters of Zhejiang, Fujian, and Guangdong.
This kind of fish is meat-like, has the advantages of fast growth, strong disease resistance, etc. It is a good breed that has promotion value in marine fish.
First, the biological characteristics
The shape of the scallop was similar to that of the Japanese sashimi, with six cheek holes. However, unlike the Japanese sashimi, the caudal fin is wedge-shaped, its eyes are large, its head length is 5.4 times the eye diameter, and its body is grayish-gray. The scale of the lateral line is obvious.
1. Inhabitation habits: The eel catfish usually prefers to swim in the lower layers of the water. It only swims to the upper layer during feeding activities, and swims to the water layer during the hungry or breeding season. Broodstock is active in the upper mid-tier during the breeding season both at night and during the day. The eel's temperament is mild, seldom jumps, and can be mixed with fish such as eel and barracuda.
2. Growth and development: The length of the body length of A. sinensis grows significantly before 20cm, but the weight gain is not obvious. When the body length reaches 20cm or more, with the growth and development of the individual, the weight gain is more obvious, indicating that the individual development of the scallop striated at this stage not only from body length but also in body height, body width, skeleton and internal organ system All have been fully developed. From the initial stage of cultivation, the body length is 3-5cm, and the breeding period is 120 days. The body length can be increased to more than 35cm, the body weight can be increased to 400-600g, and the average body weight can reach 500g or more. Compared with the codfish cultured in the same pond, it has obvious growth advantages.
3. Ingestion and feeding methods: The feeding habit of the horny scorpionfish is animal, and there is no strict selection for animal foods. Picky eaters, small scads, and mixed shrimps can be used as long as the palatability can feed. The scallops have poor feeding control, especially in the juvenile stage. The ingestion of scallops accounts for about 2-16% of the weight of the fish, and the juveniles have the highest food intake. With the individual's growth, the daily feeding rate gradually decreased. The food intake of scallops is closely related to the temperature. When the water temperature is 6Â°C, the daily food intake is only about 2% of the body weight. When the water temperature is 18-20Â°C, the food intake is 12-16% of the body weight. - The daily food intake at 30.5Â°C is 10-12% of body weight. In addition, the type of bait also has a certain influence on the amount of food fed by scallops. Therefore, in the course of artificial breeding, if the daily food intake of the fish is found to decrease, the type of bait may be temporarily replaced. The palatability of the feed also affects the food intake of the fish. Therefore, the size of the feed pellets must be carefully observed during the culture process and adjustments should be made at any time.
4. Temperature and salinity: The adaptability range of the temperature of the yellow pecker is 3-33Â°C, the suitable growth temperature is 18-28Â°C; the adaptability to the salinity is 14-33 â€°, the suitable growth salinity It is 18-30 inches.
Second, the artificial seedling technology of the horny sorghum mainly introduces the collection, transportation, hatching of the fertilized eggs, and the cultivation techniques of larvae and larvae.
1. Collection of fertilized eggs: The broodstock can lay eggs in large cages or concrete pools. Fertilized eggs show semi-submerged and semi-floating conditions when seawater salinity is less than 27 ,, but fertilization occurs when salinity increases to 33 â€°. The eggs are buoyant. The eggs can be collected using a small 80-mesh cage or the eggs can be removed by hand into a suitable container.
2. Transportation of fertilized eggs: Eggs can be collected in drums or small cages and inflated with air pumps. The egg is best transported by oxygen in a plastic bag during transportation. Each bag (303070 cm) is filled with 4 kg of water, water accounts for 1/3 of the bag capacity, and oxygen accounts for 2/3. 150-300g fertilized eggs can be placed in each bag, and the transportation time can reach 4-10 hours, and the survival rate can reach 85%.
3. Incubation of fertilized eggs: fertilized eggs can be incubated in cement pools or glass jars, and the oviposition density can be controlled at 40,000-60,000 grains/m3. The water temperature is controlled at 18-24Â°C, and gradually varies with the development stage of larvae. Increase water temperature. The salinity is controlled at about 27 ,, and is inflated throughout the incubation process. Add 5-7 ppm EDTA and 1 ppm furazolidone to the hatching water. The fertilized eggs hatch at larvae after 36-40 hours at 20Â°C.
4. Cultivation of larvae and juveniles: After the larvae ruptured the membrane, the yolk was used as a nutrient and the rotifers began to be eaten on the fourth day. Artemia nauplii (i.e., juvenile fish stages) could be fed after 15 days of age. Feeding four times a day, the number of feedings each time can be determined according to the feeding situation. It is best to feed the bait in the pool after the food is basically consumed. When entering the juvenile stage, the length of the fish can reach 1.0-1.2 cm, and the habit of colony can be transferred to the earth pond for cultivation.
Earth ponds Cultured juvenile scallop juveniles should be carried out in an outdoor earth pond shed. Clearance ponds and sterilisation should be performed in the cultivating pools, approximately 10 to 15 days before the larvae are fed. When juveniles are released, there should be a certain amount of bait organisms in the water. The temperature of the water is preferably controlled to be above 20Â°C. The minimum temperature of the individual weather should not be less than 12Â°C, and the maximum temperature cannot exceed 26Â°C. Therefore, in the Tianjin area, juveniles are best placed in outdoor earthen ponds in late April. The density is about 100,000 per acre. In addition to cultivating natural biological feed, bait should also be fed with rotifers, braised young animals, adult worms, or larvae, etc., and fed twice a day. When juveniles grow to more than 2.5cm, they can be put into ponds for culture.
5. Fry transport: generally can take two methods of transport: First, oxygen bags transported by oxygen, each bag can be placed 3-5cm fish species about 300, 5-7 hours of transport time, the survival rate of about 90%; The second method is to transport with canvas barrels, and it needs to be inflated during transportation. About 5,000 tails per square meter can be placed. Both transportation methods require attention to heat and direct light.
Third, the earthworm pond breeding
Gracilaria is a new breed of marine aquaculture. The growth rate of this species of fish is fast, and it can reach the specifications of the commodity that year. Because there is no information on the cultivation of striated scallops in earthen ponds at the moment, only us 98 , 99 years two years of earth pond farming situation of é»„ å§‘ å§‘ fish.
1. Pond conditions: The intensive fish ponds, sedimentation tanks, and primary evaporation ponds of salt farms can bred the fish. Intensive ponds need to be dredged and disinfected. During the cultivation process, the salinity of the pond water can be kept stable (14â€°-33â€°).
2. Breeding mode 1 Single-cultivation pond: In mid and late May, when the natural water temperature rises to around 15Â°C, fish species above 2.5cm can be stocked, and the stocking density is 300-500 tails/mu, after 120 days of breeding The average body length can be increased to 30-40cm and the body weight can reach 400-600g/tail, which has obvious growth advantages compared with the squid raised in the same environment.
Polyporus umbellatus and polyculture of shrimp: In the same pond, Oriental prawns and scallops are cultured. Before the saplings are placed, the pond can be blocked into two blocks, and a piece accounts for 4/5 of the total pond area. Eastern Prawns were released at the end of April or early May. Another area of â€‹â€‹1/5 was launched in late May. By mid-July, the temperature of the water will increase, and the middle of the shrimp will be taken to reduce the risk of shrimp disease. Then the fish will be spread out to block the fish and shrimps to raise fish and shrimp.
3 large water surface nesting: The current large-scale sedimentation pond pool or the primary evaporation pond in the salt field is the so-called polyculture is actually the natural Nan Miao's custody, operability is very low, yield and benefits are difficult to estimate. If you use a larger mesh filter when you enter the water, only catch other miscellaneous fish, try to enter the small shrimps and other food organisms. In mid-to-late May, seedlings weighing 2.5 cm or more were placed at a density of about 50 amu per mu. After feeding for 150 days or so, the individuals of the fish were large, generally up to 500 g or more.
3. Aquaculture management 1 Water quality control: Water quality should be kept fresh, conditional ponds, and a small amount of freshwater can be added to reduce the salinity at the early stage of seedlings. In the rainy season, depending on the precipitation, the water salinity can be maintained at 20â€°. the above. 18-28Â°C is the optimal temperature range for the growth of Ailanthorhynchus, and dissolved oxygen should be kept above 4.5mg/L. High-density farming should use aerators.
2 Feed and feeding: The bait of the scallop is mainly based on animal feed such as Artemia and small trash fish. The frozen squid needs to be completely thawed and then rinsed and then fed. The individual has larger frozen fish. Should be cut into small pieces, rinse and then feed.
In intensive culture ponds (including centralized conservation) where the body length of the fry is less than 12cm, a conditional field can be fed to Artemia adults or freshwater â€œfish and fishâ€, small shrimp or minced fish; 12cm or more, the main cast Feed small shrimps and shrimp, should be scheduled, fixed-point, quantitative feeding, feeding twice a day, feeding the amount of 10-12% of the total weight of fish, should be set in the pond bait station, regular inspection and cleaning . According to the situation of bait, determine a reasonable amount of feeding.
The above-mentioned bait and feeding method are for the first two farming methods, and the cultivation in the large water surface is relatively simple to operate, but only in the later period when the biological living food in the natural water is insufficient, the quantitative feeding Small junk fish shrimp.
Fourth, the fish disease prevention
Although the disease resistance is strong, it can also occur under artificial conditions. It is described as follows:
1. Bacterial gill disease pathogen: rod-shaped bacteria Symptoms: sick fish body color black, slow swimming, external stimulation unresponsive, loss of appetite, fish weight loss. After catching the diseased fish, it can be seen that the skin of the diseased fish larvae is congested and inflamed, and the mucus of the silkworm is increased and swollen. Some of them are light red, and the bruises are purple, and a small bleeding point can be seen. The mucus is light yellow.
Epidemic situation: When the pool water temperature reaches 25-30 Â°C, it is prone to occur.
Prevention and control measures: In the hot season, use 10-20Kg quick lime in the whole pond every 15 days. It should be done in the sunny morning.
2. The pathogen of vertical squamous disease: Pseudomonas punctata.
Symptoms: Diseased fish swim alone, swimming slowly, fish body black, injured fish scales up, translucent liquid under the scale, serious scales off; diseased fish fin base congestion, abdominal enlargement, abdominal cavity Water, some internal organs have varying degrees of lesions.
Control methods: In the process of transport, try to prevent fish from being injured, or when transporting fry, put 1-2ppm nitrofurazone.
3. Pathogens of bacterial enteritis: Aeromonas punctiforme Symptoms: Diseased fish swim alone, swimming is slow, body color is dark, appetite is poor or not feeding. Early onset of intestinal wall inflammation, intestinal cavity without food, intestinal mucus. In the late onset, the bowel wall was red, there was no food in the intestine, only pale yellow mucus, anal swelling, and yellow mucus flowed from the anus.
Epidemiological situation: When the water temperature is popular at 18-30.5Â°C, the disease is often complicated by bacterial gill disease.
Prevention and control methods: Strictly put the bait off, the deteriorating bait can never be fed, control the appropriate amount of feeding, and prevent fish from overeating. Add furazolidazole 3-5g per 100kg of feed, or add 5-7g of fluoric acid to mix and feed. In the morning and afternoon, feed once every 3-6 days.
4. The cause of bubble disease: Some kind of gas in the water body is oversaturated or the fins of the disease can not be balanced in the water and float to the surface of the water to cause contact.
Symptoms: There is a non-directional rotation on the water, bubbles in the body bulge, the body surface redness after the sun exposure, a slight bleeding, and soon died.
Prevalence: Juveniles that generally occur below 1.5 cm, have a high mortality rate.
Prevention measures: prevent the fish movement organ from being injured; do not feed deteriorating bait; or mix 1% of the yeast tablets in the bait.
5. Causes of humeral hypoplasia: The symptoms are not yet clear: Capsular insufficiency.
Prevention and control measures: To be further studied, based on our experience in nursery for the past two years, it may be caused by injury or malnutrition. Therefore, in the nursery stage, special attention should be paid to avoid causing juvenile fish injuries, food ingredients should be comprehensive, and food species. To diversify.