Since last year, the Beijing Aquatic Technology Promotion Station has successively introduced famous aquaculture species such as freshwater sharks to the suburbs of our city. These varieties have just been introduced into our city. Therefore, here we briefly introduce their breeding techniques for the general farmers. .
First, freshwater sharks:
Freshwater shark belongs to the genus Mangko and Miscanthus. It is commonly known as Pangasiusus Sutchi. It is mainly distributed in Southeast Asia. It has three colors: black, white and gray. It is mainly divided into river systems and lake systems. The species are the freshwater river sharks of the river system, the crystal river sharks and the Malaya white sharks of the lake series, the black sharks of the Malayalam, and the Thai hybrid black sharks. Black is commonly known as freshwater black shark, white is commonly known as freshwater white shark, among which the first-class Malayan grey shark is introduced to China in 2000.
The grey shark of the Malaya River is flat on its side and has a dorsal bulge on its back. Its head is flat and conical, with short kisses and lower jaw. The diaphragm is not connected to the cheeks. It is large and has the function of breathing air. In addition, some people think that this fish also has cartilage similar to sea sharks, whales, black worms, and scutellaria. It contains chondroitin sulfate, which is of high nutritional value and medicinal value.
The benthic life of the fish camp is omnivorous fish dominated by carnivorous meat. It is very bulimia, has a rapid growth rate, and is large in size and adaptable to the environment. The fish species can grow to 1500-2000 grams in that year. This fish swimming fast, sexual cowardice, once disturbed by the outside world that is constantly in the water to leap. The disadvantage is that the ability to resist low temperatures is relatively weak and it is impossible to naturally overwinter in northern China. When the water temperature drops below 18°C, the amount of food consumed and activity is significantly reduced. The water temperature continuously falls below 12°C and begins to die. The fish's requirements for water temperature and feed are similar to that of tilapia, and the cost of raising the fish is similar to that of tilapia, and the fish is more disease resistant than tilapia.
The fish is mature late, feeding for 3-4 years, and weighing more than 3 kg to breed. The breeding season is from June to September every year. Eggs are laid once a year. The eggs are small, sticky, yellow-green, and transparent. At present, there is no self-complication in China.
Second, South American white shrimp:
Penaeus vannamei, also known as white-leg shrimp, is native to the Pacific Ocean off South America and resembles China's prawn. Its normal body color is pale blue-gray, and its shell is thin. It is currently the world's highest total aquaculture production. one.
(i) Living habits:
Penaeus vannamei is a broad-salt, wide-temperate shrimp that likes to inhabit the seabed or sandy bottom. The optimum temperature range is 18-32°C, salinity is 1-40 ‰, and PH can grow normally at 7.7-9.0. The shrimp is omnivorous and has low requirements for animal feed. General requirements of feed protein can be normal growth in more than 20%. Like other crustaceans, Penaeus vannamei has a one-time increase in the length of each molting, and the molting interval is about 20 days.
(B) Farming features:
Penaeus vannamei has the advantages of rapid growth, strong disease resistance, strong adaptability to environmental changes, low feed requirements, ability to breed under dilute conditions, high meat processing rate, and delicious meat taste.
(III) Northern pond breeding methods:
1. Pond selection and preparation: The shrimp pond area is 3-5 mu. The soil quality is loam or clay soil. The water supply is sufficient, the water quality is good, and the drainage is convenient. Before the release of the seedlings, the bottom of the pond shall be cleaned, gate nets shall be installed, and the dredging shall be used to remove the harm, filter the water, and fertilize the water quality.
2. Temporary rearing of shrimp seedlings: Conditional areas should be kept for a period of time before the shrimps enter the pool. In doing so, on the one hand, they can adjust their adaptability to fresh water, and on the other hand they can improve the survival rate of shrimp seedlings.
3. Stocking of shrimp:
(1) Preparation before stocking: pond disinfection, water injection and fertility;
(2) Stocking of shrimp: Under the conditions of suitable water temperature and rich dissolved oxygen, the salinity of the holding tank and the aquaculture pond was measured respectively, and the salinity of the culture pond was adjusted to a level similar to that of the holding pond and then the seedlings were released. When the seedlings are released, the packaging bag is not opened first, and the packaging bag is immersed in the pool water. When the water temperature in the bag approaches the water temperature of the pool water, the shrimp seedlings are put into the pool. It should be noted that it is advisable to put the seedlings in the upwind outlet of the pond.
(3) Stocking density: According to the size, quality, and culture level of the shrimp, it is adjusted. It can be estimated using the formula below. Shrimp stocking amount = shrimp pond area (mu) * planned mu yield (kg) * Expected shrimp per kilogram of mantissa/predicted survival rate.
4. Cultivation management of Penaeus vannamei:
(1) Feed type: Penaeus vannamei is an omnivorous animal, so it can eat plankton in water, and can also eat fresh food and compound feed. In short, it is edible as long as it is rich in nutrients and easily digested and absorbed.
(2) Feeding technology: The process of breeding white shrimp must be scientifically fed. According to the density of shrimp seedlings, individual size, different growth stages of shrimp seedlings and other conditions. In the initial stage of general stocking (2-5 cm), plankton is abundant in the shrimp pond, and there is no need to supplement formula feed; mid-breeding (6-10) centimeters is a significant growth period of the shrimp body length, so the amount of feeding should be increased. The feed requires good quality and high protein content. At the same time, it is necessary to add dehulling substances in the feed to facilitate the growth of the shrimp skin. In the later period of culture (more than 10 cm), the weight of the white shrimp is significantly increased. In order to increase the yield, it is necessary to strengthen the feeding in order to obtain the ideal Yield and commodity shrimp specifications.
(3) Water quality management: Shrimp have high requirements for water quality, so they should constantly change the water and open aerators in the breeding process to ensure fresh water and rich dissolved oxygen. At the same time, the salinity, pH value, ammonia nitrogen, and nitrite of pool water should be regularly monitored. When poor water quality occurs, measures should be taken in time to avoid loss.
(4) Prevention and control of shrimp disease: For shrimp disease, prevention is important. During the aquaculture process, disinfection should be performed every 10-15 days, and the feeding sites for key areas such as bait should be kept clean, and the remaining baits should be promptly removed. Conditional can regularly feed the bait to prevent disease.
(5) Xuntang: During the entire cultivation process, the farmer should insist on several times a day to inspect the pond, check whether the water inlet and outlet are leaking, shrimp activity, eating conditions, molting, and whether there is any disease.
First, freshwater sharks:
Freshwater shark belongs to the genus Mangko and Miscanthus. It is commonly known as Pangasiusus Sutchi. It is mainly distributed in Southeast Asia. It has three colors: black, white and gray. It is mainly divided into river systems and lake systems. The species are the freshwater river sharks of the river system, the crystal river sharks and the Malaya white sharks of the lake series, the black sharks of the Malayalam, and the Thai hybrid black sharks. Black is commonly known as freshwater black shark, white is commonly known as freshwater white shark, among which the first-class Malayan grey shark is introduced to China in 2000.
The grey shark of the Malaya River is flat on its side and has a dorsal bulge on its back. Its head is flat and conical, with short kisses and lower jaw. The diaphragm is not connected to the cheeks. It is large and has the function of breathing air. In addition, some people think that this fish also has cartilage similar to sea sharks, whales, black worms, and scutellaria. It contains chondroitin sulfate, which is of high nutritional value and medicinal value.
The benthic life of the fish camp is omnivorous fish dominated by carnivorous meat. It is very bulimia, has a rapid growth rate, and is large in size and adaptable to the environment. The fish species can grow to 1500-2000 grams in that year. This fish swimming fast, sexual cowardice, once disturbed by the outside world that is constantly in the water to leap. The disadvantage is that the ability to resist low temperatures is relatively weak and it is impossible to naturally overwinter in northern China. When the water temperature drops below 18°C, the amount of food consumed and activity is significantly reduced. The water temperature continuously falls below 12°C and begins to die. The fish's requirements for water temperature and feed are similar to that of tilapia, and the cost of raising the fish is similar to that of tilapia, and the fish is more disease resistant than tilapia.
The fish is mature late, feeding for 3-4 years, and weighing more than 3 kg to breed. The breeding season is from June to September every year. Eggs are laid once a year. The eggs are small, sticky, yellow-green, and transparent. At present, there is no self-complication in China.
Second, South American white shrimp:
Penaeus vannamei, also known as white-leg shrimp, is native to the Pacific Ocean off South America and resembles China's prawn. Its normal body color is pale blue-gray, and its shell is thin. It is currently the world's highest total aquaculture production. one.
(i) Living habits:
Penaeus vannamei is a broad-salt, wide-temperate shrimp that likes to inhabit the seabed or sandy bottom. The optimum temperature range is 18-32°C, salinity is 1-40 ‰, and PH can grow normally at 7.7-9.0. The shrimp is omnivorous and has low requirements for animal feed. General requirements of feed protein can be normal growth in more than 20%. Like other crustaceans, Penaeus vannamei has a one-time increase in the length of each molting, and the molting interval is about 20 days.
(B) Farming features:
Penaeus vannamei has the advantages of rapid growth, strong disease resistance, strong adaptability to environmental changes, low feed requirements, ability to breed under dilute conditions, high meat processing rate, and delicious meat taste.
(III) Northern pond breeding methods:
1. Pond selection and preparation: The shrimp pond area is 3-5 mu. The soil quality is loam or clay soil. The water supply is sufficient, the water quality is good, and the drainage is convenient. Before the release of the seedlings, the bottom of the pond shall be cleaned, gate nets shall be installed, and the dredging shall be used to remove the harm, filter the water, and fertilize the water quality.
2. Temporary rearing of shrimp seedlings: Conditional areas should be kept for a period of time before the shrimps enter the pool. In doing so, on the one hand, they can adjust their adaptability to fresh water, and on the other hand they can improve the survival rate of shrimp seedlings.
3. Stocking of shrimp:
(1) Preparation before stocking: pond disinfection, water injection and fertility;
(2) Stocking of shrimp: Under the conditions of suitable water temperature and rich dissolved oxygen, the salinity of the holding tank and the aquaculture pond was measured respectively, and the salinity of the culture pond was adjusted to a level similar to that of the holding pond and then the seedlings were released. When the seedlings are released, the packaging bag is not opened first, and the packaging bag is immersed in the pool water. When the water temperature in the bag approaches the water temperature of the pool water, the shrimp seedlings are put into the pool. It should be noted that it is advisable to put the seedlings in the upwind outlet of the pond.
(3) Stocking density: According to the size, quality, and culture level of the shrimp, it is adjusted. It can be estimated using the formula below. Shrimp stocking amount = shrimp pond area (mu) * planned mu yield (kg) * Expected shrimp per kilogram of mantissa/predicted survival rate.
4. Cultivation management of Penaeus vannamei:
(1) Feed type: Penaeus vannamei is an omnivorous animal, so it can eat plankton in water, and can also eat fresh food and compound feed. In short, it is edible as long as it is rich in nutrients and easily digested and absorbed.
(2) Feeding technology: The process of breeding white shrimp must be scientifically fed. According to the density of shrimp seedlings, individual size, different growth stages of shrimp seedlings and other conditions. In the initial stage of general stocking (2-5 cm), plankton is abundant in the shrimp pond, and there is no need to supplement formula feed; mid-breeding (6-10) centimeters is a significant growth period of the shrimp body length, so the amount of feeding should be increased. The feed requires good quality and high protein content. At the same time, it is necessary to add dehulling substances in the feed to facilitate the growth of the shrimp skin. In the later period of culture (more than 10 cm), the weight of the white shrimp is significantly increased. In order to increase the yield, it is necessary to strengthen the feeding in order to obtain the ideal Yield and commodity shrimp specifications.
(3) Water quality management: Shrimp have high requirements for water quality, so they should constantly change the water and open aerators in the breeding process to ensure fresh water and rich dissolved oxygen. At the same time, the salinity, pH value, ammonia nitrogen, and nitrite of pool water should be regularly monitored. When poor water quality occurs, measures should be taken in time to avoid loss.
(4) Prevention and control of shrimp disease: For shrimp disease, prevention is important. During the aquaculture process, disinfection should be performed every 10-15 days, and the feeding sites for key areas such as bait should be kept clean, and the remaining baits should be promptly removed. Conditional can regularly feed the bait to prevent disease.
(5) Xuntang: During the entire cultivation process, the farmer should insist on several times a day to inspect the pond, check whether the water inlet and outlet are leaking, shrimp activity, eating conditions, molting, and whether there is any disease.
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