Paddlefish Breeding Technology
October 21 05:03:15, 2018
The Polyldon spathula belongs to the order Diptera, Paddlefish, and is distributed in large rivers and associated lakes, reservoirs, and coastal areas along the central and northern United States. Paddlefish is one of the two species of paddlefish currently in existence in the world (the other is Psephuru gladius, a species unique to China). It is a large-scale freshwater economic fish whose eggs, meat and skin have extremely high economic value. The meat is extremely delicious, and there is no intertwined meat. The kiss is rich in collagen, and the salesperson is well-nourished. It is a splendid dish. The eggs are processed into caviar and canned in small cans. At the current international market, the price is 150-500 US dollars per kilogram, and the hide is the finest raw material for leather. Young fish kiss like duck bills, such as "elephant", the body crystal Run, swimming state specific, one of the rare ornamental fish. First, the biological characteristics 1, living habits paddlefish is a cartilaginous fish, in the shape of a spoon-shaped long kiss, about one-third of the body length. The trunk is streamlined, flat on the side of the tail, scales are degraded, and the surface is smooth, the eyes are very small, the mouth is not stretchable under the kiss, and the plum blossoms are covered by the lid. The pectoral fins are smaller and lower; the ventral fins are abdominal; the dorsal fins originate behind the pelvic fins; the caudal fins are bifurcated and the caudal peduncle is covered with a stalked scale. Body color: the back is grayish black, and the sides are pale and grayish on the sides. Paddlefish is a kind of pure freshwater fish that can live in rivers, lakes and ponds inland all year round, and does not need to swim like a Chinese sturgeon. The optimum temperature range is 0-27°C. It is reused in the upper layer of the water. The suitable range of Ph is 6.5-8, and the oxygen requirement for water body is more than 5mg/L. 2. The spawning spoonfish lives for zooplankton for life. Larval larvae are mainly small-branched broilers and also eat egg yolk, fish meal, and shrimp meal. Although the hatched larvae have some cracks, they cannot be closed, but only by swimming constantly to obtain oxygen and bait. The size of the bait should be compatible with its mouth cracks, such as rotifers. Can only passively ingest food, the order of requirements for the bait is: rotifers a small Cladocera and copepods a large Cladocera and Cobra foot. Artificial feeding requires feeding 9-10 times a day, feeding once every 2 hours, and feeding 3-5 grams of red worms or other small zooplankton per thousand fry. Juveniles have active feeding ability only after they have developed a kiss. Their feeding method is swallowing, devouring zooplankton, small fish and shrimp. When the feed is insufficient, the larvae bite each other seriously. It is necessary to increase the feeding amount of bait and reduce the density of fry breeding. After 12 cm in length, the carp seedlings developed well and their feeding organs developed. Under captive feeding, zooplankton generally eats buoyant bait. Second, seed cultivation and transportation 1. Artificial breeding technique Paddlefish is more mature than Chinese sturgeon and Daphnia magna. Male sexual maturity is mostly 7-9 years, females are mostly 8-10 years, and generally choose 18kg or so. Female fish to oxytocin, male to female ratio is generally 2:1, paddlefish broodstock no obvious side sexual characteristics. In general, female individuals are large, abdominal distension, swollen, congested and slightly loosened near the urogenital port, and easy insertion of the urogenital port with little fingers; male individuals are smaller and have more protrusions on the head. A more reliable method is to observe the gonad with the naked eye. At present, the effect of oxytocin is better in frozen paddlefish pituitary and luteinizing hormone releasing hormone (LRH-A). The use of pituitary glands is more common. The females are generally used in two pituitary/tailed males and males in one pituitary/tail. After thawing the pituitary, 1.5 ml of deionized water was added, and it was intraperitoneally injected on the day after grinding. A needle injection method was used with a success rate of 65%. Fertility with LRH-A is also effective, with a dose of 10 mg per kilogram. More than two-needle injection method, gonads developed good broodstock can basically empty. Promote the use of broodstock after estrus in the oviposition, insemination, detackification, hatching, so as to obtain fry. It should be noted that 24°C is the sub-lethal temperature for fry hatching and 28°C is the lethal temperature, while a water temperature below 11°C will also reduce the survival rate and inhibit their growth. The optimum water temperature range is 20-24°C. In addition, larval rearing should be carried out indoors to avoid death caused by excessive temperature difference. 2, seedling cultivation in two stages, the first stage from the full-length 2-3cm raised to 6-7cm. Usually held in cement tank or cement tank for 15 days or so full-length can reach 6-7cm, during the cultivation, dissolved oxygen is maintained at 6mg/L or more, feed palatability, sufficient amount of bait (mainly Cladocera). Prevent excessive density and try to avoid self-inflation. After being 6-7cm in length, it is put into a pond for cultivation. The pond area requires 3-5 mu, the water depth is 1.5-2cm, and drainage is convenient. Each pond is equipped with an aerator of 1.5 kilowatts. The pond water is drained and the quicklime is disinfected. 300-400 kilograms of mu are used to kill miscellaneous fish, aquatic plants, germs and predators. The growth temperature of 2-37 °C can be, the most suitable 25-32 °C, a week before the pond, do fertilization to cultivate good water quality, with green manure or manure. 3 days later, the pool sprinkled milk, slag, dosage 5kg/mu. In order to promote the massive breeding of horny horns, water nets must be used before the lower tang to catch a net and remove maggots and debris. The temperature difference between the water temperature in the pool and the container of the fish should not exceed 1°C. Operation should be carried out in the evening. The main breeding method is monoculture, and it can be used together with a small amount of herbivorous fish. Do not mix with fierce fish. The stocking density is 1000-1500 tail/mu. In addition to fertilizing and cultivating water in the aquaculture process, soybean milk (2kg/mu), crushed glutinous rice flour, rice bran, or special grain foods are also fed to maintain the water quality of the fertilizer, live, tender, and cool. 3, transport fertilized eggs transport, each bag of fertilized eggs 07000-10000, plus foam (some even add ice bags), to buffer shock and heat insulation, during transport, encounter fish fry began to film, should Timely change of water, re-oxygenation packaging. For the transportation of young cubs, the cubs must exercise and suspend the water in the cradle for 4-6 hours to excrete the feces. In addition, the water in the oxygenated bags must occupy 30-35% of the volume of the plastic bags. Third, disease control paddlefish juvenile fish prone to enteritis, stomatitis, acne, water mold, as long as the right medicine can be cured. 10-15 cm fish species are less likely to die, and paddlefish are very sensitive to drugs, especially heavy metal salts, so be careful when using drugs. In the case of trichodinid parasites, 15-25% formalin may not be used to kill, nematodes or trematodes may be parasitized, 2 ppm potassium permanganate, or less than 75 ppm formalin bath may be used, and CuSO4 may be prohibited during juvenile stage. Chlorine-containing drugs, antibiotic soaking concentration of about 4ppm. Fourth, adult fish breeding and fishing (pond, lakes and reservoirs) 1, pond culture <1> sets of spatula, in various types of aquaculture spawning paddlefish, in order to increase spawning paddlefish broodstock reserves, do not take up too much water. For example, a second instar spatula of 20 species can be reared in a grass carp or ichthyosis broodstock. After more than 10 months of experimentation, the maximum individuals were 4.8 kg and the average tail weight was 4.1 kg. <2> The main spawning paddlefish, the main fish species is paddlefish, mixed grass carp, white pelicans, gully, etc. in the pond, larvae larvae body length 25cm / tail, can be stocked 200-300 per acre, polyculture 150 / mu. Polyculture specifications must be less than paddlefish. Adult fish farming is not suitable for small area or high yield, high density of dissolved oxygen. 2. Releasing of lakes and reservoirs Many studies have shown that paddlefish that are released in reservoirs are richer in plankton than in rivers, and that they grow faster. If rivers in reservoir reservoirs have suitable spawning sites, paddlefish in reservoirs will multiply. Proliferate, form a larger population and become the main target for fishing. Paddlefish, widely distributed in the United States in the Mississippi River Basin and its neighboring 22 states, the main population lived in the river. The Mississippi River basin in the United States has a continental temperate climate. It has similarities with the Yangtze River basin and most of the areas north of the Yangtze River. It shows that the ecological conditions of most reservoirs in China are suitable for growth requirements of paddlefish. The lake and reservoir reserve paddlefish size should be greater than 40cm, so that the survival rate is higher. When the fish body weight reaches 0.75kg or more, it can exceed 2kg in the following year, and it can exceed 3kg at the end of the third year. The lakes and reservoirs should pay attention to fish farming: the fish facilities should be built to prevent the released stockings from fleeing. 3. The moderate temperament of paddlefish catchers is similar to that of alum. In pond culture, net catching can be used, and the first net can catch more than 90% of the fish. For large and medium-sized water surfaces, most paddlefish can be captured using the catch, catch, spine, and Zhang fishing methods. The biological characteristics of paddlefish indicate rapid growth, symbiosis, wide appetite, low cost, high value, and economic advantages. It will become a fine variety in China's carp aquaculture industry, and it is suitable for vigorous promotion of culture in lakes, reservoirs, ponds, etc. to the waters. With the continuous improvement of aquaculture technology, it can be predicted that in the near future, paddlefish will become another popular brand new breed of aquaculture in China.