Abstract : This paper describes the internal and external morphological structure of freshwater sharks in detail, and photographs their appearance, internal structure, jaws, jaws, anus and urogenital holes. The living habits, feeding habits, ecological habits, breeding habits and growth characteristics of freshwater sharks were introduced. A preliminary study was conducted on the artificial production of freshwater sharks and artificial insemination experiments were conducted. Finally, the method of fry breeding for freshwater sharks was briefly described. This article points out the future research directions, development trends and breeding methods of freshwater sharks, laying a good foundation for the further promotion of freshwater sharks. Keywords: freshwater shark, artificial propagation, breeding, culture, fry cultivation, introduction 1. Introduction of freshwater shark scientific name Pangasius sutchi (Fowler) [12], also known as Siamese, tiger sharks, Crystal Budding Fish (English name Paien), Bajin fish or BaSa (15) are taxonomically classified as Siluriformes (Pangasiidae). Mainly distributed in inland rivers and lakes in Malaysia, Thailand, Laos, Cambodia, Vietnam and other countries, it is one of the famous freshwater aquaculture high-yielding fishes with excellent economic traits in Southeast Asia, and is also a popular fishing target for local people [7]. Apart from serving as food fish, the fish also has good ornamental value, and contains more chondroitin sulfate with higher nutritional value and medicinal value in its cartilage tissue [6], especially in Hong Kong and Macao. Considered to be high-end expensive fish, it is in short supply [4]. Freshwater sharks are divided into five river systems and lake systems. There are five ecological types. In 1978, we introduced the Thai hybrid Palsewai (dark black), originally known as freshwater blue shark, originating in Thailand. At that time, Thailand's ADK's Thai-Chinese, Cai Youguang, presented 4,000 fish fry with a total length of about 3cm to the Pearl River Fisheries Research Institute of the Chinese Academy of Fishery Sciences. After reaching the destination, it was able to survive 2,200 tails [1]. In 1998, we introduced the Malaysian white shark (White Fowler), originally known as freshwater white shark, originating in Malaysia. In addition, there is the Black Fowler (Black Fowler, commonly known as the freshwater black shark) in the lake system, and the freshwater shark (Buah) (body grey, commonly known as the freshwater grey shark) and Crystal River Shark in the river system. (Permata) (color red and white, commonly known as freshwater red shark). At present, these species are only tested in a few places such as Guangdong and Fujian, and there are few reports on the artificial reproduction and scale farming of this fish [6][10][13][16][17][18]. In order to further promote the cultivation of freshwater sharks, adjust the structure of aquaculture species, and expand the proportion of famous aquaculture, we conducted a preliminary study on the biological characteristics of the fish at the Hainan Breeding Base of Beijing Aquatic Technology Promotion Station, and for the first time in the country An artificial oxytocin test was conducted. 2. Biological characteristics 2.1 Morphological characteristics Freshwater shark Viet Nam transliterated as "kabasa" (CaBaSa, Yueyu Ca means "fish", Ba means "three", Sa means "fat" means), meaning " Three fat fish." Because the fish during the growth process, there are three large oil fat accumulation in the abdominal cavity, accounting for about 5 to 8% of body weight, which is rare among other fish [13][14]. Freshwater sharks are smooth and scaleless with mucus; they have a flat lateral line (and upper and lower branches) from the lid.
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Body back blue, body side gray, abdomen silvery white. The base color of each fin is dark gray, the middle is milky white, and the edges are grayish black with orange-yellow markings. Dorsal fins DI-6 to 7; anal fins A.3 to 5, 29 to 31; pectoral fins PI-9 to 10; pelvic fins VI-5 to 8. The total length is 1.12 to 1.16 times the body length; it is 1.06 to 1.11 times the length of the fork. The body length was 3.35 to 3.78 times the body height, 4.21 to 4.53 times the head length, 6.58 to 6.65 times the tail shank length, 3.13 to 3.17 times the length of the anal fin base, and 1.48 to 1.51 times the length of the side cord. The head length was 2.64-2.68 times the length of the kiss, 1.59-1.61 times the length of the head behind the eye, 8.98-9.14 times the eye diameter, 1.45-1.71 times the eye distance, 3.24-3.65 times the distance between the nose, and mouth 1.95 to 2.48 times the horizontal crack. The caudal peduncle was 1.78 to 1.93 times taller than the caudal peduncle. The jaws should be 1.16 to 1.18 times longer than the buns; 1.65 to 1.69 times the eye diameter. The length of the anal fin base was 16.62 to 19.14 times the length of the lipid fin base. The body length is 1.78 to 1.85 times the starting point of the dorsal fin to the starting point of the fat fin. Freshwater sharks are spindle-shaped, long in shape and prominent in front of the flat dorsal fins, with the back gradually flattened. The head is small and flat and conical. Its back is smooth. Generally, the head length is one-fifth of the body length. The width is wide, the kiss is short, the mouth is sub-lower, and it is not stretchable, horizontally cracked, the mouth crack is slightly curved, and the depth is relatively small. Big. The upper jaw was slightly longer than the lower jaw, and the upper and lower jaws were densely curved with small villi. The teeth were plate-like and not connected in the middle. Pear bones and cheekbones also have the same small teeth. The tongue is spade-like and not free. Thin, undeveloped, with two pairs of whiskers, often broken. A pair of jaws is required, very short, reaching the middle of the eye; a pair of beaks, slightly longer than the jaws, up to the base of the pectoral fins. Eyes large, nearly round, lower, located in the mouth crack slightly later, the location of the front and close to the kiss end, eye circle red and yellow, wide eye separation, the middle slightly convex. The borehole is relatively large, the diaphragm is well developed, and it is connected to the left and right, but it is not connected to the isthmus.鳃耙 Five pairs, shorter, strip-shaped, smaller than the length of the cocoon silk [2], each bow has only outer coffin, the first cocoon bow has obvious outer cocoon, and the outer cocoon has 5-6+15-18, Other bows are not obvious. Two nostrils, before and after the nostrils, but close to each other. The abdomen is large and round with no ventral edges. The anus is slightly reddish white and separates from the urine hole. The distance is greater than the distance from the urethra to the starting point of the anal fin. The dorsal fin is located at the highest point of the back, with a hard spine at the leading edge and shorter than the adjacent soft stripe, without serrations. There is a lamellar fat fin from the beginning of the dorsal fin to the base of the caudal fin. The fat fins are smaller and are located at the anterior of the anal fin ends. The pectoral fins are thoracic, the hard spines are thick, and the ends are serrated. The pelvic fins are small, the starting point is located behind the dorsal fin base, and is close to the starting point of the pectoral fins from the starting point of the anal fins. The anal fin base is rather long, the posterior extension and the caudal fin base, and the distance from the posterior edge to the caudal fin base is much smaller than the base length. The tail is positive-tailed and the bifurcation is significant. The cockroach is very long and has the function of breathing air. The back part is in a thin tube with a slightly pointed tip. It extends into the muscle below the vertebra in the body cavity and has a fistula in the front of the ventral surface. The kidney is located on the dorsal side of the iliac crest, closely adjoining the back wall of the body cavity, the front part is two fine forks, the middle part is from left to right, and the back part protrudes to both sides but is not symmetrical. The kidney's posterior end extends out of the ureter and connects the bladder. After the bladder is urogenital sinus, urogenital sinus is long tubular. The liver is divided into left and right leaves, yellow-brown, and the left lobe is larger than the right lobe [3]. The gallbladder is buried in the liver and is relatively large, slender, dark green or milky white and is located below the left hepatic lobe. Larger stomach, "V" shaped. The spleen is diffuse and dark red. Under natural conditions, the intestine is short and its length is generally 1.1 times the body length. However, in the culture conditions, due to feeding compound feed, the intestine is long and bent in the abdominal cavity, its length is 2 to 3 times the body length. The testes of the male testes are symmetrical on both sides and are dendritic. Each side is divided into multiple leaves and slightly petaloid. Male testes of sexually mature males are milky white and pale pink when immature. The ovaries of the females are paired and the ovaries are closed. The mesentery is particularly large in the body and is suspended in a variety of internal organs to fix its position. The membrane is rich in a large number of blood vessels. 2.2 Living habits Freshwater shark camp benthic life. Swimming is quick, lively and timid, and when it is disturbed, it constantly squanderes and bumps in the water. Under natural conditions, freshwater sharks prefer to live in deep, watery shades of water, and prefer to live under aquatic floating plants. Its disease resistance and ability to adapt to the living environment are strong, sometimes due to careless handling and the fish body
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External abrasion does not affect the health of the fish. The most remarkable feature of the fish is that once the environment is comfortable, the floating surface of the cluster often turns over and makes a call. 2.3 Ingesting habits Freshwater sharks are omnivorous fish that are predominantly carnivorous. This fish is greedy and has a high appetite. Juveniles use baits, such as rotifers, flatworms, cladocera, copepods, aquatic animals, aquatic insect larvae, etc., or various algae, and can also feed on artificial feeds. Adult fish feed on a variety of aquatic plants and artificial compound feeds, but also eat leftovers of leftovers, human and animal manure, wheat bran, bean cakes, fishmeal and livestock and poultry residues [6]. 2.4 Ecological habits 2.4.1 Applicable scope Freshwater sharks are tropical fish and have low resistance to low temperature. Normal temperature suitable for 20 ~ 30 °C, the best growing temperature is 24 ~ 28 °C. When the water temperature was below 18°C, the food consumption and activity were significantly reduced. When the water temperature was 15°C, the activity was slow, and the reaction was dull and sluggish. When the water temperature dropped to 14°C or exceeded 35°C, the food intake was basically stopped; When the water temperature is lower than 12°C for several consecutive days, shock or even death occurs [11]. The suitable pH is 6 ~ 7.2 [5]. 2.4.2 Tolerance to hypoxia Freshwater sharks are densely divided into a large number of blister-like respiratory chambers, and are highly capillaryized into important respiratory organs. They can breathe in the air, so they have strong tolerance to hypoxia. It can also live and survive for a long time. When the fishes of the carp family are severely floating, they can still live normally [4]. However, under low dissolved oxygen conditions, its growth rate was significantly slowed [6]. 2.5 Growth characteristics The growth rate of freshwater sharks is quite fast. Under proper cultivation conditions, after half a year to one year, weight gain can be about 0.75 to 2 kg. If cultured in natural waters such as rivers, their growth and development speed is much faster than in ponds. This fish is a large quail. Its maximum individual body length can reach more than 1m and its weight can reach more than 30kg [1]. 2.6 Breeding habits Under natural conditions, freshwater sharks are mostly naturally spawn upstream of the river [13]. It is difficult to reach sexual maturity under artificial rearing conditions, especially for female fish whose ovarian maturation coefficient is very low, and the maturation coefficient of broodstock for 4 to 5 years in the spawning season is less than 5%, while the oil fat mass in the body occupies the body weight. About 8% seriously affected the artificial reproduction of the fish. Therefore, the sexual maturity is late, and the body weight can be more than 3 to 4 kg before reproduction. Mature individuals do not have obvious side sexual characteristics. Males are generally mature after 3 years of age and can extrude semen. Females need more than 4 years of age to mature, and spawning period is from June to September each year, which is a year of spawning fish [14]. In vitro fertilization, small eggs, light green, nearly circular, transparent, sticky. The egg diameter is about 0.9~1.2mm. The amount of fledgling depends on the weight of the fish and the condition of the nutritional development. The absolute amount of eggs of the fish is generally several hundred thousand. 3. Artificial propagation of 3.1 material The broodstock of Hainan Breeding Base of Beijing Fisheries Technology Promotion Center was introduced from Malaysia in early 2000. It is raised in ponds and after three years of careful cultivation, the weight of female fish is mostly 3.5 to 4.5 kg. The males weigh more than 2.0 to 2.5 kg. Aphrodisiacs include LH-RH-A for fish, HCG and DOM and their solvents. For oxytocin use, there are syringes (20ml and 5ml two sizes), injection needles, physiological saline, mortar, fish nest (made of palm bark), thermometers, towels, white porcelain pots, fish clips, and bamboo skewers. - 3 -
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3.2 Methods 3.2.1 Broodstock Breeding Parents that have large individuals, good health, and good fullness are to be fortified and promoted. Both female and male fish are placed in an area of ​​1.76 mu of 22# soil pond. As the temperature rises, the water temperature also rises. The gonad development of the broodstock began to increase, and the amount of feed was gradually increased. The daily feed of tilapia adult fish pellets was changed from 5kg to two feedings per day. Tilapia adult fish particles were fed on top of each day in the afternoon. Feed 7.5kg. During the breeding period, the water temperature is 22 to 30°C. The pond water comes from the nearby Hushan Reservoir, which is rich in plankton. 3.2.2 Artificial oxytocinification When the pond water temperature is above 24°C, two batches of artificial oxytocin production are conducted successively. The two batches of oxytocin used in artificial oxytocin are commonly used oxytocin in domestic fish, namely LH-RH-A, DOM and HCG. After being dissolved in physiological saline, injection is performed by means of intramuscular injection. Female and male fish were injected at the same time, but the number of injections and the injection time of the two batches had different results for comparison. The time, number of injections, volume and injection time of two batches of artificial oxytocin, oxytocin and its dosage are shown in Table 1. During the trial, a 1:1 male to female ratio was matched. The first batch of ten co-produced groups, each pair. The second batch of co-production five groups, each pair. The injected broodstock was placed in a round cement spawning pool (the first batch of brood fish was placed in a 2# spawning pool with a diameter of 8m; the third group of the second batch of broodstock was put into a spawning pool of 2#, the other two The group was placed in a 1# spawning pond with a diameter of 6m. After each oxytocin injection, 0.5 to 1 hour of water was given to stimulate the estrus of the broodstock. 3.2.3 Artificial insemination and laying eggs On April 6th, we artificially inseminated the second batch of broodstock that was artificially inactivated. Before artificial insemination, the fish nests are first disinfected, washed and soaked in water for use. At the same time, artificial insemination and cloth-laying tools such as towels, white porcelain pots, and fish clips are prepared. The development of broodstock was checked again 22 to 24 hours after the injection of the third needle: When the abdomen of the fish was gently squeezed, the eggs of the female fish could flow out smoothly, and the male fish would also flow out of the semen, but not smooth. Prepare the broodstock to be artificially inseminated. First, the male and the female, and the male, with the head of the fish facing downwards, wipe the dried fish body with a towel and gently squeeze the fish eggs into a clean egg container. Since fish eggs are viscous eggs, dry insemination is used. After squeezing the eggs, quickly squeeze the semen of the male fish into the egg container. Then, stir the eggs with a clean hand while adding clean water, so that the eggs are combined and fertilized in the vessel, and then the fertilized eggs are evenly and quickly. The ground was spread on the fish nest, and then the fish nest was transferred to an artificial hatching in a hatching pool of microfluidic water on a bamboo basket. Usually the eggs of a female fish are paired with the sperm of two male fish. - 4 -
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Table 1. Freshwater sharks artificial labor method Oxygen dose Dose Injection volume Injection time Water temperature Average body weight First batch of spawned first injection LH-RH-A DOM 4ug/kg 2mg/kg 2ml/tail 18:30 24°C Second injection LH-RH-A DOM HCG 10ug/kg 4mg/kg 3500IU/kg 2ml/tail 19:00 24°C 6kg/group Second instalation LH-RH-A DOM 5ug/kg (1#) 2ug/ Kg(2#) 2mg/kg ♀ 2ml/tail cercariae 1.5ml/tail 11:00 28°C Second injection of LH-RH-A DOM HCG ♀10ug/kg ♂5ug/kg 2mg/kg 1000IU/kg (♀) ♀2ml/tail cercariae 1.5ml/tail 11:00 26°C 6kg/group third injection LH-RH-A HCG ♀10ug/kg ♂5ug/kg 1500IU/kg (♀) ♀2ml/tail lice 1.5ml/tail 10:00 24°C 4. Fry culture 4.1 Fry transportation test The fry was imported from Malaysia on March 13. It was transferred from Xiamen to Hainan Breeding Base. It was divided into nine boxes, each containing two bags. Each bag had two layers of plastic transported with oxygen. Eighteen bags of a total of 30,000 fish with an average size of 3cm were placed at the base of the three
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Test soil in a pond. Among them, 4 # ponds have an area of ​​2.58 mu, and about 12,000 fish fry; 5 ponds have an area of ​​2.42 mu, and about 12,000 fry are reared; 13 ponds have an area of ​​1.80 mu and about 6,000 fry are stocked. When the seedlings are released, the fry is first tested for about 10 minutes, and then the seedlings are injected into the pool. The temperature of the pool water is 23°C. A small amount of dead fish was removed from the next day, and the survival rate reached 90%. 4.2 Feeding The domestication begins with the use of crushed shrimp slices on the second day after hatching, while striking the pool wall with wooden sticks to induce conditioned reflexes. At first, only a few fish began to eat, and then gradually increased. Ten days later, all fish began feeding and domestication was successful. Four days after planting, the fry stopped. From the fifth day, the mixture of soymilk and shrimp was splashed and gradually changed. Two weeks later, the tilapia powder began to be fed and started to eat less. After a few days, it was fed in large quantities. 4.3 Routine management Routine management is performed according to conventional farming methods. Feeding 4 to 6 times a day, feeding a small number of times at the beginning, but because the fish is gluttonous, it should be neither wasted nor overeat. Regularly measure the water quality, check the weight and body length of the sample, and frequently add new water. There was no fish disease during the cultivation and the growth was good. 5. Results and Discussion (1) Freshwater sharks are widely cultivated in Thailand and Southeast Asia. The longest history of freshwater shark farming in Thailand has been over 100 years. The fish lived in rivers, ponds and swamps. In the past, it was unable to mature eggs in ponds and floating cages. Most of them were naturally spawned upstream of the river, and they depended on catching natural fry from rivers. In 1960, the Ministry of Fisheries used the method of injecting pituitary glands to produce food successfully. Since then, the aquaculture has developed rapidly. It has become one of the most important economic fish that currently ranks first in the country's freshwater aquaculture production. Freshwater sharks do not have the problem of overwintering of broodstock in Thailand. The reproductive season is from January to October and it breeds once or twice a year [7]. However, in our country, due to the significant differences in climate between the South and the North, the large-scale breeding of freshwater sharks and the production of commercial fish are largely limited and affected. In 1989, Zheng Wenxuan and Pan Shuhua obtained a large number of freshwater sharks with artificial mutations [8]. In the future, scientific research in this area should be intensified, and advanced technologies such as bioengineering and genetic engineering should be applied to jointly tackle the issues and further develop new varieties with wide adaptability so as to further increase the commercial value and ornamental value of freshwater sharks. Promotion value. (2) Freshwater sharks have the advantages of rapid growth, less disease, miscellaneous feeding, low oxygen tolerance, and strong adaptability, in terms of the breeding process and effects of fingerlings and fry. The fish is similar to the local tilapia cultivation in Hainan, but the price is much higher than that of tilapia. And now, especially in the Hong Kong and Macao markets (Hong Kong market price of 80 to 100 Hong Kong dollars per kilogram) [4] is considered a valuable food fish and in short supply, high aquaculture efficiency, is worth promoting the fine varieties of freshwater culture. (3) Freshwater sharks are simple to breed, flexible and diversified breeding methods, and low feed requirements. The chondroitin sulphate they have has a high medicinal value (the market value of commodity fish is 60-80 yuan per kilogram) [6], with significant economic benefits. . And its good meat quality, no intermuscular thorns, delicious taste, general freshwater fish taste bad after freezing, but freshwater sharks frozen meat taste unchanged [9], which is a major advantage of freshwater sharks, by consumers like. Freshwater sharks are one of the better famous fish culture species in China and have great development potential. (4) Freshwater sharks are tropical fish. Their cold resistance is weak, and they cannot overwinter under natural conditions. This poses great difficulties for winter-maintenance and seed breeding, and to a great extent limits its further promotion. However, the fish can be cultivated on a large scale in parts of the south and a few areas with warm water conditions in the north. Unconditional farms can catch all commercial fish before the winter solstice.
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city. (5) A preliminary study of the biology and artificial reproduction techniques of freshwater sharks has basically explored the fish's living habits, ecological environment, and reproductive physiology and characteristics, explored the effects of fat metabolism on reproduction, and found effective breeding of mature broodstock. method. The key technology is: how to reduce the accumulation of body fat in freshwater sharks (due to excessive accumulation of fat must affect the development of the egg). Regular measures such as regular flushing, timely aeration and aeration, deeper pond water depth, and reduced broodstock stocking density can be used to promote the maturation and development of the egg and effectively increase the maturation coefficient of the broodstock. This is a high-end economic fish for freshwater sharks. The future development of this category has laid a good foundation. (6) Explored techniques for artificial insemination and artificial insemination of freshwater sharks. The fish approximates the spawning type of Chinese quail and squid, and its suitable spawning temperature is 28-30°C [7]. The preliminary mastery of the fish's special production techniques. The type of oxytocic acid, the number of injections and the dose of oxytocin should be flexibly handled according to the development of the broodstock, water temperature and climatic conditions during oxytocin production. Do not behave in a dogmatic manner. The operation should be light and fast during artificial insemination so as not to injure the broodstock and avoid direct sunlight. In addition, individuals with mature broodstock that are artificially inseminated should not be too large. Otherwise, they will not only have a large dose of oxytocin but also be difficult to handle. The key to artificial insemination is to accurately grasp the time of spawning. If it is too early, it will not only cause no eggs, but will also cause loss of production due to disturbing; if over the physiological maturity period, excessive maturation of fish eggs will result in low fertility, even Fertilization. This artificial oxytocin and insemination experiment was not achieved due to the two-tier factors of broodstock maturity and weather instability. (7) A series of relevant experiments were conducted in the study of artificial reproduction of freshwater sharks. For example, the effects of different oxytocin drugs, different injection times, different injection doses, different injection times, different injection sites, and different spawning environments on the productivity of freshwater sharks were tested. However, all kinds of tests are at the stage of exploration. Affected by operating technology, experience and environmental conditions, the results do not achieve the intended purpose. (8) It is strongly recommended that local research institutes, extension stations, fisheries, and specialized households actively introduce new talents for freshwater aquaculture such as transplanting freshwater sharks, learn from the advanced experience of successful provinces and cities, and develop from extensive culture to intensive culture; and develop from monoculture to polyculture; The rearing food chain has long been developing fish stocks with short food chains; the development of artificially formulated pellet feeds and the development of integrated aquaculture in agriculture, animal husbandry, and fishing; and the growth of artificially controlled fishes and the gradual development toward industrialized production methods. In line with local conditions, with points and areas, through market regulation, we will gradually form intensive and large-scale fish breeding bases, which will effectively promote the development of fishery production. - 7 -
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References [1] Wang Yutang. Freshwater shark breeding technology. China Fisheries, 2001, (2): 47-48. [2] Fang Zhanqiang, Zheng Wenyu, Xiao Zhi et al. Ultrastructural observation of Sophia philippinarum [J]. Journal of Fisheries,2001,25(6):489～491. [3] Fang Zhanqiang, Zheng Wenxuan, Fu Lulan. The ultrastructure of the liver of Sophora japonica. China Fisheries Science, 2002, 9(4): 296-297. [4] Ye Qingsheng, Liang Baihan, Jiang Cunian. Crystal pudding fish breeding technology. Fisheries Science and Technology, 2000,(1):30. [5] Lin Kewen. Freshwater shark breeding techniques. Scientific fish farming, 2001, (8): 15-16. [6] Lin Kewen. Pond farming freshwater shark technology. Freshwater Fisheries, 2002, 32(1): 27~28. [7] Zheng Wenkai. Thai quail farming. Fisheries Science and Technology Information, 1986, (4): 16-17. [8] Zheng Wentao, Pan Yuhua. 1. A preliminary report of the Sophora japonica test for obtaining a large number of body color variations artificially. Fisheries Science and Technology Information, 1990, (5): 147-148. [9] Zhao Wenhan. Artificial breeding of crystal pudding. Beijing Fisheries, 2003, (1): 35-36. [10] Huang Yanhe et al. Su's round belly high-yielding aquaculture technology. Freshwater Fisheries, 2000, 30(5): 9-10. [11] Fu Fangcai. Freshwater shark breeding technology. Aquaculture, 2002, (3): 9-10. [12] Lou Yundong. The status quo and countermeasures of research on fish introduction in China. Fisheries Journal, 1999, 24(2): 186-188. [13] Wei Yusheng. The artificial breeding of Basha fish was successful. Freshwater Fisheries, 1998, 28(2): 36. [14] Wei Yusheng, Yan Changjiang et al. Study on the biology of Basha fish in Mekong River Basin. Freshwater Fisheries, 1996, 26(6): 25-26. [15] Wu Shanxue. Freshwater shark breeding technology. China Fisheries, 2002, (8): 48. [16] Jan H.Mol. Reproductive biology of the neotropical armoured catfish Hoplosternum littorale (Siluriformes-Callichthyidae): a synthesis stressing the role of the floating bubble nest. Aquat. Living Resour, 1998, 11(3): 173-185. [17] Bornbusch AH Redescription and reclassification of the silurid catfish Apodoglanis fumessi Fowler (Siluriformes : Siluridae) with diagnoses of three intrafamilies silurid subgroups. Copeia, 1991, (4): 1070~1084. [18] Xiao, WH et al. Systematics of Xenocyprinae (Teleostei:Cyprinidae): taxonomy, biogeography and coevolution of a special group restricted in East Asia. Mol. Phylogent. Evol, 2001, 18(5):163-173. - 9 -
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Biological Characteristics of Pangasius sutchi and Test of Artificial Propagation on it HaiPeng WANG,Lei YU Life Science and Technology Institute, Dalian Fisheries University, Dalian (116023) Abstract This paper describes internal construction and exterior appearance of Pangasius sutchi in detail. And we took a We observed the skill of the artificial ripening and made Artificial insemination experiment at the same time. At last, this article describes in brief the method of fry rearing, points out that the research direction, developmental trend, and cultural way. It establishes the foundation of the further expansion of Pangasius sutchi. Keywords: Pangasius sutchi, artificial propagation, biology, culture, fry rearing - 10 -
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Body back blue, body side gray, abdomen silvery white. The base color of each fin is dark gray, the middle is milky white, and the edges are grayish black with orange-yellow markings. Dorsal fins DI-6 to 7; anal fins A.3 to 5, 29 to 31; pectoral fins PI-9 to 10; pelvic fins VI-5 to 8. The total length is 1.12 to 1.16 times the body length; it is 1.06 to 1.11 times the length of the fork. The body length was 3.35 to 3.78 times the body height, 4.21 to 4.53 times the head length, 6.58 to 6.65 times the tail shank length, 3.13 to 3.17 times the length of the anal fin base, and 1.48 to 1.51 times the length of the side cord. The head length was 2.64-2.68 times the length of the kiss, 1.59-1.61 times the length of the head behind the eye, 8.98-9.14 times the eye diameter, 1.45-1.71 times the eye distance, 3.24-3.65 times the distance between the nose, and mouth 1.95 to 2.48 times the horizontal crack. The caudal peduncle was 1.78 to 1.93 times taller than the caudal peduncle. The jaws should be 1.16 to 1.18 times longer than the buns; 1.65 to 1.69 times the eye diameter. The length of the anal fin base was 16.62 to 19.14 times the length of the lipid fin base. The body length is 1.78 to 1.85 times the starting point of the dorsal fin to the starting point of the fat fin. Freshwater sharks are spindle-shaped, long in shape and prominent in front of the flat dorsal fins, with the back gradually flattened. The head is small and flat and conical. Its back is smooth. Generally, the head length is one-fifth of the body length. The width is wide, the kiss is short, the mouth is sub-lower, and it is not stretchable, horizontally cracked, the mouth crack is slightly curved, and the depth is relatively small. Big. The upper jaw was slightly longer than the lower jaw, and the upper and lower jaws were densely curved with small villi. The teeth were plate-like and not connected in the middle. Pear bones and cheekbones also have the same small teeth. The tongue is spade-like and not free. Thin, undeveloped, with two pairs of whiskers, often broken. A pair of jaws is required, very short, reaching the middle of the eye; a pair of beaks, slightly longer than the jaws, up to the base of the pectoral fins. Eyes large, nearly round, lower, located in the mouth crack slightly later, the location of the front and close to the kiss end, eye circle red and yellow, wide eye separation, the middle slightly convex. The borehole is relatively large, the diaphragm is well developed, and it is connected to the left and right, but it is not connected to the isthmus.鳃耙 Five pairs, shorter, strip-shaped, smaller than the length of the cocoon silk [2], each bow has only outer coffin, the first cocoon bow has obvious outer cocoon, and the outer cocoon has 5-6+15-18, Other bows are not obvious. Two nostrils, before and after the nostrils, but close to each other. The abdomen is large and round with no ventral edges. The anus is slightly reddish white and separates from the urine hole. The distance is greater than the distance from the urethra to the starting point of the anal fin. The dorsal fin is located at the highest point of the back, with a hard spine at the leading edge and shorter than the adjacent soft stripe, without serrations. There is a lamellar fat fin from the beginning of the dorsal fin to the base of the caudal fin. The fat fins are smaller and are located at the anterior of the anal fin ends. The pectoral fins are thoracic, the hard spines are thick, and the ends are serrated. The pelvic fins are small, the starting point is located behind the dorsal fin base, and is close to the starting point of the pectoral fins from the starting point of the anal fins. The anal fin base is rather long, the posterior extension and the caudal fin base, and the distance from the posterior edge to the caudal fin base is much smaller than the base length. The tail is positive-tailed and the bifurcation is significant. The cockroach is very long and has the function of breathing air. The back part is in a thin tube with a slightly pointed tip. It extends into the muscle below the vertebra in the body cavity and has a fistula in the front of the ventral surface. The kidney is located on the dorsal side of the iliac crest, closely adjoining the back wall of the body cavity, the front part is two fine forks, the middle part is from left to right, and the back part protrudes to both sides but is not symmetrical. The kidney's posterior end extends out of the ureter and connects the bladder. After the bladder is urogenital sinus, urogenital sinus is long tubular. The liver is divided into left and right leaves, yellow-brown, and the left lobe is larger than the right lobe [3]. The gallbladder is buried in the liver and is relatively large, slender, dark green or milky white and is located below the left hepatic lobe. Larger stomach, "V" shaped. The spleen is diffuse and dark red. Under natural conditions, the intestine is short and its length is generally 1.1 times the body length. However, in the culture conditions, due to feeding compound feed, the intestine is long and bent in the abdominal cavity, its length is 2 to 3 times the body length. The testes of the male testes are symmetrical on both sides and are dendritic. Each side is divided into multiple leaves and slightly petaloid. Male testes of sexually mature males are milky white and pale pink when immature. The ovaries of the females are paired and the ovaries are closed. The mesentery is particularly large in the body and is suspended in a variety of internal organs to fix its position. The membrane is rich in a large number of blood vessels. 2.2 Living habits Freshwater shark camp benthic life. Swimming is quick, lively and timid, and when it is disturbed, it constantly squanderes and bumps in the water. Under natural conditions, freshwater sharks prefer to live in deep, watery shades of water, and prefer to live under aquatic floating plants. Its disease resistance and ability to adapt to the living environment are strong, sometimes due to careless handling and the fish body
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External abrasion does not affect the health of the fish. The most remarkable feature of the fish is that once the environment is comfortable, the floating surface of the cluster often turns over and makes a call. 2.3 Ingesting habits Freshwater sharks are omnivorous fish that are predominantly carnivorous. This fish is greedy and has a high appetite. Juveniles use baits, such as rotifers, flatworms, cladocera, copepods, aquatic animals, aquatic insect larvae, etc., or various algae, and can also feed on artificial feeds. Adult fish feed on a variety of aquatic plants and artificial compound feeds, but also eat leftovers of leftovers, human and animal manure, wheat bran, bean cakes, fishmeal and livestock and poultry residues [6]. 2.4 Ecological habits 2.4.1 Applicable scope Freshwater sharks are tropical fish and have low resistance to low temperature. Normal temperature suitable for 20 ~ 30 °C, the best growing temperature is 24 ~ 28 °C. When the water temperature was below 18°C, the food consumption and activity were significantly reduced. When the water temperature was 15°C, the activity was slow, and the reaction was dull and sluggish. When the water temperature dropped to 14°C or exceeded 35°C, the food intake was basically stopped; When the water temperature is lower than 12°C for several consecutive days, shock or even death occurs [11]. The suitable pH is 6 ~ 7.2 [5]. 2.4.2 Tolerance to hypoxia Freshwater sharks are densely divided into a large number of blister-like respiratory chambers, and are highly capillaryized into important respiratory organs. They can breathe in the air, so they have strong tolerance to hypoxia. It can also live and survive for a long time. When the fishes of the carp family are severely floating, they can still live normally [4]. However, under low dissolved oxygen conditions, its growth rate was significantly slowed [6]. 2.5 Growth characteristics The growth rate of freshwater sharks is quite fast. Under proper cultivation conditions, after half a year to one year, weight gain can be about 0.75 to 2 kg. If cultured in natural waters such as rivers, their growth and development speed is much faster than in ponds. This fish is a large quail. Its maximum individual body length can reach more than 1m and its weight can reach more than 30kg [1]. 2.6 Breeding habits Under natural conditions, freshwater sharks are mostly naturally spawn upstream of the river [13]. It is difficult to reach sexual maturity under artificial rearing conditions, especially for female fish whose ovarian maturation coefficient is very low, and the maturation coefficient of broodstock for 4 to 5 years in the spawning season is less than 5%, while the oil fat mass in the body occupies the body weight. About 8% seriously affected the artificial reproduction of the fish. Therefore, the sexual maturity is late, and the body weight can be more than 3 to 4 kg before reproduction. Mature individuals do not have obvious side sexual characteristics. Males are generally mature after 3 years of age and can extrude semen. Females need more than 4 years of age to mature, and spawning period is from June to September each year, which is a year of spawning fish [14]. In vitro fertilization, small eggs, light green, nearly circular, transparent, sticky. The egg diameter is about 0.9~1.2mm. The amount of fledgling depends on the weight of the fish and the condition of the nutritional development. The absolute amount of eggs of the fish is generally several hundred thousand. 3. Artificial propagation of 3.1 material The broodstock of Hainan Breeding Base of Beijing Fisheries Technology Promotion Center was introduced from Malaysia in early 2000. It is raised in ponds and after three years of careful cultivation, the weight of female fish is mostly 3.5 to 4.5 kg. The males weigh more than 2.0 to 2.5 kg. Aphrodisiacs include LH-RH-A for fish, HCG and DOM and their solvents. For oxytocin use, there are syringes (20ml and 5ml two sizes), injection needles, physiological saline, mortar, fish nest (made of palm bark), thermometers, towels, white porcelain pots, fish clips, and bamboo skewers. - 3 -
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3.2 Methods 3.2.1 Broodstock Breeding Parents that have large individuals, good health, and good fullness are to be fortified and promoted. Both female and male fish are placed in an area of ​​1.76 mu of 22# soil pond. As the temperature rises, the water temperature also rises. The gonad development of the broodstock began to increase, and the amount of feed was gradually increased. The daily feed of tilapia adult fish pellets was changed from 5kg to two feedings per day. Tilapia adult fish particles were fed on top of each day in the afternoon. Feed 7.5kg. During the breeding period, the water temperature is 22 to 30°C. The pond water comes from the nearby Hushan Reservoir, which is rich in plankton. 3.2.2 Artificial oxytocinification When the pond water temperature is above 24°C, two batches of artificial oxytocin production are conducted successively. The two batches of oxytocin used in artificial oxytocin are commonly used oxytocin in domestic fish, namely LH-RH-A, DOM and HCG. After being dissolved in physiological saline, injection is performed by means of intramuscular injection. Female and male fish were injected at the same time, but the number of injections and the injection time of the two batches had different results for comparison. The time, number of injections, volume and injection time of two batches of artificial oxytocin, oxytocin and its dosage are shown in Table 1. During the trial, a 1:1 male to female ratio was matched. The first batch of ten co-produced groups, each pair. The second batch of co-production five groups, each pair. The injected broodstock was placed in a round cement spawning pool (the first batch of brood fish was placed in a 2# spawning pool with a diameter of 8m; the third group of the second batch of broodstock was put into a spawning pool of 2#, the other two The group was placed in a 1# spawning pond with a diameter of 6m. After each oxytocin injection, 0.5 to 1 hour of water was given to stimulate the estrus of the broodstock. 3.2.3 Artificial insemination and laying eggs On April 6th, we artificially inseminated the second batch of broodstock that was artificially inactivated. Before artificial insemination, the fish nests are first disinfected, washed and soaked in water for use. At the same time, artificial insemination and cloth-laying tools such as towels, white porcelain pots, and fish clips are prepared. The development of broodstock was checked again 22 to 24 hours after the injection of the third needle: When the abdomen of the fish was gently squeezed, the eggs of the female fish could flow out smoothly, and the male fish would also flow out of the semen, but not smooth. Prepare the broodstock to be artificially inseminated. First, the male and the female, and the male, with the head of the fish facing downwards, wipe the dried fish body with a towel and gently squeeze the fish eggs into a clean egg container. Since fish eggs are viscous eggs, dry insemination is used. After squeezing the eggs, quickly squeeze the semen of the male fish into the egg container. Then, stir the eggs with a clean hand while adding clean water, so that the eggs are combined and fertilized in the vessel, and then the fertilized eggs are evenly and quickly. The ground was spread on the fish nest, and then the fish nest was transferred to an artificial hatching in a hatching pool of microfluidic water on a bamboo basket. Usually the eggs of a female fish are paired with the sperm of two male fish. - 4 -
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Table 1. Freshwater sharks artificial labor method Oxygen dose Dose Injection volume Injection time Water temperature Average body weight First batch of spawned first injection LH-RH-A DOM 4ug/kg 2mg/kg 2ml/tail 18:30 24°C Second injection LH-RH-A DOM HCG 10ug/kg 4mg/kg 3500IU/kg 2ml/tail 19:00 24°C 6kg/group Second instalation LH-RH-A DOM 5ug/kg (1#) 2ug/ Kg(2#) 2mg/kg ♀ 2ml/tail cercariae 1.5ml/tail 11:00 28°C Second injection of LH-RH-A DOM HCG ♀10ug/kg ♂5ug/kg 2mg/kg 1000IU/kg (♀) ♀2ml/tail cercariae 1.5ml/tail 11:00 26°C 6kg/group third injection LH-RH-A HCG ♀10ug/kg ♂5ug/kg 1500IU/kg (♀) ♀2ml/tail lice 1.5ml/tail 10:00 24°C 4. Fry culture 4.1 Fry transportation test The fry was imported from Malaysia on March 13. It was transferred from Xiamen to Hainan Breeding Base. It was divided into nine boxes, each containing two bags. Each bag had two layers of plastic transported with oxygen. Eighteen bags of a total of 30,000 fish with an average size of 3cm were placed at the base of the three
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Test soil in a pond. Among them, 4 # ponds have an area of ​​2.58 mu, and about 12,000 fish fry; 5 ponds have an area of ​​2.42 mu, and about 12,000 fry are reared; 13 ponds have an area of ​​1.80 mu and about 6,000 fry are stocked. When the seedlings are released, the fry is first tested for about 10 minutes, and then the seedlings are injected into the pool. The temperature of the pool water is 23°C. A small amount of dead fish was removed from the next day, and the survival rate reached 90%. 4.2 Feeding The domestication begins with the use of crushed shrimp slices on the second day after hatching, while striking the pool wall with wooden sticks to induce conditioned reflexes. At first, only a few fish began to eat, and then gradually increased. Ten days later, all fish began feeding and domestication was successful. Four days after planting, the fry stopped. From the fifth day, the mixture of soymilk and shrimp was splashed and gradually changed. Two weeks later, the tilapia powder began to be fed and started to eat less. After a few days, it was fed in large quantities. 4.3 Routine management Routine management is performed according to conventional farming methods. Feeding 4 to 6 times a day, feeding a small number of times at the beginning, but because the fish is gluttonous, it should be neither wasted nor overeat. Regularly measure the water quality, check the weight and body length of the sample, and frequently add new water. There was no fish disease during the cultivation and the growth was good. 5. Results and Discussion (1) Freshwater sharks are widely cultivated in Thailand and Southeast Asia. The longest history of freshwater shark farming in Thailand has been over 100 years. The fish lived in rivers, ponds and swamps. In the past, it was unable to mature eggs in ponds and floating cages. Most of them were naturally spawned upstream of the river, and they depended on catching natural fry from rivers. In 1960, the Ministry of Fisheries used the method of injecting pituitary glands to produce food successfully. Since then, the aquaculture has developed rapidly. It has become one of the most important economic fish that currently ranks first in the country's freshwater aquaculture production. Freshwater sharks do not have the problem of overwintering of broodstock in Thailand. The reproductive season is from January to October and it breeds once or twice a year [7]. However, in our country, due to the significant differences in climate between the South and the North, the large-scale breeding of freshwater sharks and the production of commercial fish are largely limited and affected. In 1989, Zheng Wenxuan and Pan Shuhua obtained a large number of freshwater sharks with artificial mutations [8]. In the future, scientific research in this area should be intensified, and advanced technologies such as bioengineering and genetic engineering should be applied to jointly tackle the issues and further develop new varieties with wide adaptability so as to further increase the commercial value and ornamental value of freshwater sharks. Promotion value. (2) Freshwater sharks have the advantages of rapid growth, less disease, miscellaneous feeding, low oxygen tolerance, and strong adaptability, in terms of the breeding process and effects of fingerlings and fry. The fish is similar to the local tilapia cultivation in Hainan, but the price is much higher than that of tilapia. And now, especially in the Hong Kong and Macao markets (Hong Kong market price of 80 to 100 Hong Kong dollars per kilogram) [4] is considered a valuable food fish and in short supply, high aquaculture efficiency, is worth promoting the fine varieties of freshwater culture. (3) Freshwater sharks are simple to breed, flexible and diversified breeding methods, and low feed requirements. The chondroitin sulphate they have has a high medicinal value (the market value of commodity fish is 60-80 yuan per kilogram) [6], with significant economic benefits. . And its good meat quality, no intermuscular thorns, delicious taste, general freshwater fish taste bad after freezing, but freshwater sharks frozen meat taste unchanged [9], which is a major advantage of freshwater sharks, by consumers like. Freshwater sharks are one of the better famous fish culture species in China and have great development potential. (4) Freshwater sharks are tropical fish. Their cold resistance is weak, and they cannot overwinter under natural conditions. This poses great difficulties for winter-maintenance and seed breeding, and to a great extent limits its further promotion. However, the fish can be cultivated on a large scale in parts of the south and a few areas with warm water conditions in the north. Unconditional farms can catch all commercial fish before the winter solstice.
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city. (5) A preliminary study of the biology and artificial reproduction techniques of freshwater sharks has basically explored the fish's living habits, ecological environment, and reproductive physiology and characteristics, explored the effects of fat metabolism on reproduction, and found effective breeding of mature broodstock. method. The key technology is: how to reduce the accumulation of body fat in freshwater sharks (due to excessive accumulation of fat must affect the development of the egg). Regular measures such as regular flushing, timely aeration and aeration, deeper pond water depth, and reduced broodstock stocking density can be used to promote the maturation and development of the egg and effectively increase the maturation coefficient of the broodstock. This is a high-end economic fish for freshwater sharks. The future development of this category has laid a good foundation. (6) Explored techniques for artificial insemination and artificial insemination of freshwater sharks. The fish approximates the spawning type of Chinese quail and squid, and its suitable spawning temperature is 28-30°C [7]. The preliminary mastery of the fish's special production techniques. The type of oxytocic acid, the number of injections and the dose of oxytocin should be flexibly handled according to the development of the broodstock, water temperature and climatic conditions during oxytocin production. Do not behave in a dogmatic manner. The operation should be light and fast during artificial insemination so as not to injure the broodstock and avoid direct sunlight. In addition, individuals with mature broodstock that are artificially inseminated should not be too large. Otherwise, they will not only have a large dose of oxytocin but also be difficult to handle. The key to artificial insemination is to accurately grasp the time of spawning. If it is too early, it will not only cause no eggs, but will also cause loss of production due to disturbing; if over the physiological maturity period, excessive maturation of fish eggs will result in low fertility, even Fertilization. This artificial oxytocin and insemination experiment was not achieved due to the two-tier factors of broodstock maturity and weather instability. (7) A series of relevant experiments were conducted in the study of artificial reproduction of freshwater sharks. For example, the effects of different oxytocin drugs, different injection times, different injection doses, different injection times, different injection sites, and different spawning environments on the productivity of freshwater sharks were tested. However, all kinds of tests are at the stage of exploration. Affected by operating technology, experience and environmental conditions, the results do not achieve the intended purpose. (8) It is strongly recommended that local research institutes, extension stations, fisheries, and specialized households actively introduce new talents for freshwater aquaculture such as transplanting freshwater sharks, learn from the advanced experience of successful provinces and cities, and develop from extensive culture to intensive culture; and develop from monoculture to polyculture; The rearing food chain has long been developing fish stocks with short food chains; the development of artificially formulated pellet feeds and the development of integrated aquaculture in agriculture, animal husbandry, and fishing; and the growth of artificially controlled fishes and the gradual development toward industrialized production methods. In line with local conditions, with points and areas, through market regulation, we will gradually form intensive and large-scale fish breeding bases, which will effectively promote the development of fishery production. - 7 -
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References [1] Wang Yutang. Freshwater shark breeding technology. China Fisheries, 2001, (2): 47-48. [2] Fang Zhanqiang, Zheng Wenyu, Xiao Zhi et al. Ultrastructural observation of Sophia philippinarum [J]. Journal of Fisheries,2001,25(6):489～491. [3] Fang Zhanqiang, Zheng Wenxuan, Fu Lulan. The ultrastructure of the liver of Sophora japonica. China Fisheries Science, 2002, 9(4): 296-297. [4] Ye Qingsheng, Liang Baihan, Jiang Cunian. Crystal pudding fish breeding technology. Fisheries Science and Technology, 2000,(1):30. [5] Lin Kewen. Freshwater shark breeding techniques. Scientific fish farming, 2001, (8): 15-16. [6] Lin Kewen. Pond farming freshwater shark technology. Freshwater Fisheries, 2002, 32(1): 27~28. [7] Zheng Wenkai. Thai quail farming. Fisheries Science and Technology Information, 1986, (4): 16-17. [8] Zheng Wentao, Pan Yuhua. 1. A preliminary report of the Sophora japonica test for obtaining a large number of body color variations artificially. Fisheries Science and Technology Information, 1990, (5): 147-148. [9] Zhao Wenhan. Artificial breeding of crystal pudding. Beijing Fisheries, 2003, (1): 35-36. [10] Huang Yanhe et al. Su's round belly high-yielding aquaculture technology. Freshwater Fisheries, 2000, 30(5): 9-10. [11] Fu Fangcai. Freshwater shark breeding technology. Aquaculture, 2002, (3): 9-10. [12] Lou Yundong. The status quo and countermeasures of research on fish introduction in China. Fisheries Journal, 1999, 24(2): 186-188. [13] Wei Yusheng. The artificial breeding of Basha fish was successful. Freshwater Fisheries, 1998, 28(2): 36. [14] Wei Yusheng, Yan Changjiang et al. Study on the biology of Basha fish in Mekong River Basin. Freshwater Fisheries, 1996, 26(6): 25-26. [15] Wu Shanxue. Freshwater shark breeding technology. China Fisheries, 2002, (8): 48. [16] Jan H.Mol. Reproductive biology of the neotropical armoured catfish Hoplosternum littorale (Siluriformes-Callichthyidae): a synthesis stressing the role of the floating bubble nest. Aquat. Living Resour, 1998, 11(3): 173-185. [17] Bornbusch AH Redescription and reclassification of the silurid catfish Apodoglanis fumessi Fowler (Siluriformes : Siluridae) with diagnoses of three intrafamilies silurid subgroups. Copeia, 1991, (4): 1070~1084. [18] Xiao, WH et al. Systematics of Xenocyprinae (Teleostei:Cyprinidae): taxonomy, biogeography and coevolution of a special group restricted in East Asia. Mol. Phylogent. Evol, 2001, 18(5):163-173. - 9 -
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Biological Characteristics of Pangasius sutchi and Test of Artificial Propagation on it HaiPeng WANG,Lei YU Life Science and Technology Institute, Dalian Fisheries University, Dalian (116023) Abstract This paper describes internal construction and exterior appearance of Pangasius sutchi in detail. And we took a We observed the skill of the artificial ripening and made Artificial insemination experiment at the same time. At last, this article describes in brief the method of fry rearing, points out that the research direction, developmental trend, and cultural way. It establishes the foundation of the further expansion of Pangasius sutchi. Keywords: Pangasius sutchi, artificial propagation, biology, culture, fry rearing - 10 -
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