Polyodon spathula belongs to the order Diptera, Paddlefish, and is distributed in large rivers and associated lakes, reservoirs, and bays in the central and northern United States. Paddlefish is one of the two species of paddlefish currently in existence in the world (the other is Psiphurus gladius, a special species in China). It is a large-scale freshwater economic fish whose eggs, meat and skin have extremely high economic value. The flesh is extremely delicious, and there is no intertwined meat. In particular, the kiss is rich in collagen and nutritious. It is the finest of the feast. Its eggs are processed into caviar and canned in small cans. The current international market is 150-500 US dollars per kilogram. Leather is a finest raw material for leather. Young fish kiss the duck's beak, such as "elephant", body crystal Run, swimming state specific, one of the cadmium fish.
one. Biological characteristics
1. Habits
The paddlefish, a species of cartilaginous fish, has a long kiss shaped like a spoon and occupies about 1/3 of its length. The trunk is streamlined, flat on the side of the tail, scales degenerate, and the surface is smooth, the eyes are very small, the mouth is not stretchable under the kiss, and the plum blossom-like pattern is covered in 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 "back gray black, both sides shallow, pale belly. Paddlefish is a pure freshwater fish, can live in the inland rivers, lakes and ponds all year round, do not need the same as Chinese sturgeon. The range is 0-37°C, living in the water layer, the suitable pH range is 6.5-8, and the oxygen requirement for water body is above 5mg/L.
2. feeding habits
Paddlefish feed on 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 constantly flowing to obtain oxygen and bait. The size of the bait should be adapted to its mouth cracks, such as rotifers. Only passive food intake, the order of requirements for feed: rotifers → small Cladocera → large Cladocera and copepods. Artificial feeding requires 9 to 10 feedings each time, feeding once every 2 hours, and feeding 3 to 5 grams of redworms or other small zooplankton per thousand fry. Only when the juveniles grow out of the snout can they have the initiative to ingest food. The feeding method is to swallow and swallow the zooplankton, small fish and shrimp. When the bait is insufficient, the larvae bite each other seriously, and it is necessary to increase the amount of bait feed and reduce the fry density. When the length of the carp seedlings exceeds 12 cm, the feeding organs are well developed and transfer to the filter-feeding method. The buoyant food of zooplankton size is commonly eaten under captivity.
two. Seed cultivation and transportation
1. Artificial propagation technology
Paddlefish are more mature than Chinese sturgeon and Daphnia magna. Male sexual maturity is usually 7-9 years, and females are usually 8-10 years. Generally, 18kg of females are selected to induce puerility, and the male to female ratio is generally 1:1. Paddlefish broodstock has 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 relatively good. The pituitary gland and luteinizing hormone-releasing hormone analogue (LRH-A) of the frozen paddlefish are relatively 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. After milling, it was intraperitoneally injected. The injection method was one needle and the success rate was 65%. With LRH-A oxytocin has a good effect, the dose is generally 10mg per kilogram of body weight, more use of two-needle injection method, the gonads developed better broodstock, can basically produce empty. After promoting estrus in the broodstock, eggs are collected, inseminated, de-adhered, and hatched 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 water temperature below 11°C will also reduce the survival rate and inhibit its growth. The optimum water temperature range is 20 to 24°C. In addition, larval rearing should be carried out indoors to avoid death caused by excessive temperature difference.
2. Seed cultivation
In two stages, the first stage is raised from 2 to 3 cm in length to 6 to 7 cm in length. Generally held in cement tank or cement tank for 15 days or so, the total length can reach 6-7 cm. During the cultivation, the dissolved oxygen is kept above 6 mg/L. The feed is suitable for feeding, and the amount of feed (mainly Cladocera) is sufficient. Prevent excessive density to avoid self-inflation. After a total length of 6 to 7 centimeters, it is put into a pond for cultivation. The pond area requires 3 to 5 mu, the water depth is 1.5 to 2 meters, and drainage and irrigation are convenient. Each pond is equipped with a 1.5-kilowatt aerator. Before stocking, the pond water shall be drained and disinfected with quick lime. The amount of mu should be 300-400 kilograms to kill miscellaneous fish, aquatic plants, pathogens and predators. Growth temperature 2 °C ~ 37 °C can be, the most suitable 25 °C ~ 32 °C, a week before the pond, do fertilization to cultivate knife water quality, with green manure or manure. After 3 days, soymilk and slag were sprinkled into the pond, and the amount of 5kg/mu promoted the horny genus. Before the lagoon, it was not necessary to use a net to remove the larvae and debris. When stocking, the temperature difference between the fish pond water temperature and the fish container should not exceed 1°C. Operation should be carried out in the evening. The main farming method is monoculture, but sometimes with herbivorous fish, do not match fierce fish, stocking density is 1000 ~ 1500 tail / mu this is good. In the breeding process, in addition to fertilizing and cultivating water quality, soybean milk (2kg/mu), glutinous rice bran and rice bran, or special pellet feed are also fed to maintain the water quality of fertilizer, live, tender and cool.
3. transport
The fertilized eggs are transported with 0.7 to 10,000 fertilized eggs per bag, plus foam (sometimes with ice packs) to cushion and insulate them. In the course of transportation, when the fish fry begins to film, it should be changed in time and recharged with oxygen. Before the transportation of the young cubs, exercise and suspend the water in the binding box for 4-6 hours to excrete the feces. In addition, the water in the oxygenated bags must account for 30%-35% of the volume of the plastic bags.
three. Disease prevention and treatment
Paddlefish larvae stage prone to enteritis, stomatitis, acne, water mold, as long as the right medicine, can be cured. Ten to 15 centimeters of fingerlings are generally not easy to die. Paddlefish are very sensitive to drugs, especially heavy metal salts, so be careful when using drugs. For trichodinid parasites, use 15% to 25% concentration of formalin to kill, nematodes or flukes parasitize, use 2ppm formalin bath, ban the use of CuSO4 and chlorine-containing drugs in juvenile stage, antibiotic soak concentration 4ppm.
four. Adult fish breeding and fishing
1. Pond culture
(1) Set a spatula: You can use paddlefish in various aquaculture waters to increase paddlefish's broodstock reserves without occupying the water surface. Taiwan can set up a second-instar paddlefish 20 tails in grass carp or catfish ponds. After 10 months of incubation, the largest individual was 4.8 kg and the average tail weight was 4.1 kg.
(2) Main spawning paddlefish: The main fish species are paddlefish, mixed grass carp, white pelicans, and gully in the pond. The larvae have a body length of 25 centimeters per tail, and 200 to 250 tails per acre, and 150 tails of mixed fish. mu. Mixed fish specifications must be less than paddlefish. Adult fish farming should not be polycultured in small areas or intensively cultivated high-yield ponds, and should be 5 to 15 mu. Because of the high yield and density of the intensive ponds, dissolved oxygen rises and falls, and round robins are very unfavorable to paddlefish.
2. Lake and reservoir discharge
Many studies have shown that paddlefish that are released in reservoirs grow faster because they are richer in phytoplankton than in rivers. If rivers in reservoir reservoirs have suitable spawning sites, paddlefish in reservoirs will multiply and multiply to form larger populations. , become the main fishing target. Paddlefish are widely distributed in the United States in the Mississippi River Basin and its neighboring 22 states. The main populations live in river channels. The Mississippi River basin in the United States has a continental temperate climate. It has similarities with the Yangtze River basin in China and most of the areas north of the Yangtze River, indicating 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 40 cm, so that the survival rate is relatively high. The fish weight can reach 0.75 kg or more in the current year, more than 2 kg in the following year, and more than 3 kg at the end of the third year. Lakes and reservoirs should pay attention to fish farming: bar fish equipment is built to prevent stocking spoonfish from fleeing.
3. Fishing
Paddlefish have a mild temperament and habits similar to those of a white stork. Pond culture. Can be caught by the net, the first net will be able to 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 that it has the advantages of rapid growth, symbiosis, wide appetite, low cost and high economic value. It will become a fine variety in the carp aquaculture industry in China, and it is suitable for the promotion of culture in lakes, reservoirs, ponds and other waters. With the continuous improvement of aquaculture technology, it can be predicted that in the near future, paddlefish will become another popular new breed of aquaculture in China.
one. Biological characteristics
1. Habits
The paddlefish, a species of cartilaginous fish, has a long kiss shaped like a spoon and occupies about 1/3 of its length. The trunk is streamlined, flat on the side of the tail, scales degenerate, and the surface is smooth, the eyes are very small, the mouth is not stretchable under the kiss, and the plum blossom-like pattern is covered in 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 "back gray black, both sides shallow, pale belly. Paddlefish is a pure freshwater fish, can live in the inland rivers, lakes and ponds all year round, do not need the same as Chinese sturgeon. The range is 0-37°C, living in the water layer, the suitable pH range is 6.5-8, and the oxygen requirement for water body is above 5mg/L.
2. feeding habits
Paddlefish feed on 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 constantly flowing to obtain oxygen and bait. The size of the bait should be adapted to its mouth cracks, such as rotifers. Only passive food intake, the order of requirements for feed: rotifers → small Cladocera → large Cladocera and copepods. Artificial feeding requires 9 to 10 feedings each time, feeding once every 2 hours, and feeding 3 to 5 grams of redworms or other small zooplankton per thousand fry. Only when the juveniles grow out of the snout can they have the initiative to ingest food. The feeding method is to swallow and swallow the zooplankton, small fish and shrimp. When the bait is insufficient, the larvae bite each other seriously, and it is necessary to increase the amount of bait feed and reduce the fry density. When the length of the carp seedlings exceeds 12 cm, the feeding organs are well developed and transfer to the filter-feeding method. The buoyant food of zooplankton size is commonly eaten under captivity.
two. Seed cultivation and transportation
1. Artificial propagation technology
Paddlefish are more mature than Chinese sturgeon and Daphnia magna. Male sexual maturity is usually 7-9 years, and females are usually 8-10 years. Generally, 18kg of females are selected to induce puerility, and the male to female ratio is generally 1:1. Paddlefish broodstock has 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 relatively good. The pituitary gland and luteinizing hormone-releasing hormone analogue (LRH-A) of the frozen paddlefish are relatively 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. After milling, it was intraperitoneally injected. The injection method was one needle and the success rate was 65%. With LRH-A oxytocin has a good effect, the dose is generally 10mg per kilogram of body weight, more use of two-needle injection method, the gonads developed better broodstock, can basically produce empty. After promoting estrus in the broodstock, eggs are collected, inseminated, de-adhered, and hatched 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 water temperature below 11°C will also reduce the survival rate and inhibit its growth. The optimum water temperature range is 20 to 24°C. In addition, larval rearing should be carried out indoors to avoid death caused by excessive temperature difference.
2. Seed cultivation
In two stages, the first stage is raised from 2 to 3 cm in length to 6 to 7 cm in length. Generally held in cement tank or cement tank for 15 days or so, the total length can reach 6-7 cm. During the cultivation, the dissolved oxygen is kept above 6 mg/L. The feed is suitable for feeding, and the amount of feed (mainly Cladocera) is sufficient. Prevent excessive density to avoid self-inflation. After a total length of 6 to 7 centimeters, it is put into a pond for cultivation. The pond area requires 3 to 5 mu, the water depth is 1.5 to 2 meters, and drainage and irrigation are convenient. Each pond is equipped with a 1.5-kilowatt aerator. Before stocking, the pond water shall be drained and disinfected with quick lime. The amount of mu should be 300-400 kilograms to kill miscellaneous fish, aquatic plants, pathogens and predators. Growth temperature 2 °C ~ 37 °C can be, the most suitable 25 °C ~ 32 °C, a week before the pond, do fertilization to cultivate knife water quality, with green manure or manure. After 3 days, soymilk and slag were sprinkled into the pond, and the amount of 5kg/mu promoted the horny genus. Before the lagoon, it was not necessary to use a net to remove the larvae and debris. When stocking, the temperature difference between the fish pond water temperature and the fish container should not exceed 1°C. Operation should be carried out in the evening. The main farming method is monoculture, but sometimes with herbivorous fish, do not match fierce fish, stocking density is 1000 ~ 1500 tail / mu this is good. In the breeding process, in addition to fertilizing and cultivating water quality, soybean milk (2kg/mu), glutinous rice bran and rice bran, or special pellet feed are also fed to maintain the water quality of fertilizer, live, tender and cool.
3. transport
The fertilized eggs are transported with 0.7 to 10,000 fertilized eggs per bag, plus foam (sometimes with ice packs) to cushion and insulate them. In the course of transportation, when the fish fry begins to film, it should be changed in time and recharged with oxygen. Before the transportation of the young cubs, exercise and suspend the water in the binding box for 4-6 hours to excrete the feces. In addition, the water in the oxygenated bags must account for 30%-35% of the volume of the plastic bags.
three. Disease prevention and treatment
Paddlefish larvae stage prone to enteritis, stomatitis, acne, water mold, as long as the right medicine, can be cured. Ten to 15 centimeters of fingerlings are generally not easy to die. Paddlefish are very sensitive to drugs, especially heavy metal salts, so be careful when using drugs. For trichodinid parasites, use 15% to 25% concentration of formalin to kill, nematodes or flukes parasitize, use 2ppm formalin bath, ban the use of CuSO4 and chlorine-containing drugs in juvenile stage, antibiotic soak concentration 4ppm.
four. Adult fish breeding and fishing
1. Pond culture
(1) Set a spatula: You can use paddlefish in various aquaculture waters to increase paddlefish's broodstock reserves without occupying the water surface. Taiwan can set up a second-instar paddlefish 20 tails in grass carp or catfish ponds. After 10 months of incubation, the largest individual was 4.8 kg and the average tail weight was 4.1 kg.
(2) Main spawning paddlefish: The main fish species are paddlefish, mixed grass carp, white pelicans, and gully in the pond. The larvae have a body length of 25 centimeters per tail, and 200 to 250 tails per acre, and 150 tails of mixed fish. mu. Mixed fish specifications must be less than paddlefish. Adult fish farming should not be polycultured in small areas or intensively cultivated high-yield ponds, and should be 5 to 15 mu. Because of the high yield and density of the intensive ponds, dissolved oxygen rises and falls, and round robins are very unfavorable to paddlefish.
2. Lake and reservoir discharge
Many studies have shown that paddlefish that are released in reservoirs grow faster because they are richer in phytoplankton than in rivers. If rivers in reservoir reservoirs have suitable spawning sites, paddlefish in reservoirs will multiply and multiply to form larger populations. , become the main fishing target. Paddlefish are widely distributed in the United States in the Mississippi River Basin and its neighboring 22 states. The main populations live in river channels. The Mississippi River basin in the United States has a continental temperate climate. It has similarities with the Yangtze River basin in China and most of the areas north of the Yangtze River, indicating 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 40 cm, so that the survival rate is relatively high. The fish weight can reach 0.75 kg or more in the current year, more than 2 kg in the following year, and more than 3 kg at the end of the third year. Lakes and reservoirs should pay attention to fish farming: bar fish equipment is built to prevent stocking spoonfish from fleeing.
3. Fishing
Paddlefish have a mild temperament and habits similar to those of a white stork. Pond culture. Can be caught by the net, the first net will be able to 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 that it has the advantages of rapid growth, symbiosis, wide appetite, low cost and high economic value. It will become a fine variety in the carp aquaculture industry in China, and it is suitable for the promotion of culture in lakes, reservoirs, ponds and other waters. With the continuous improvement of aquaculture technology, it can be predicted that in the near future, paddlefish will become another popular new breed of aquaculture in China.