Freshwater lobster breeding techniques
2018-06-15 15:01:01
In foreign countries, freshwater lobsters refer to Australian crayfish. There are more than 100 species of shrimp, but only three species can be cultivated, namely cherenuimnus, cherax deshuctou and cherax quadricinatus. The three shrimps are widely distributed in Australia, but there are obvious regional distribution characteristics. In Australia, aquaculture trials began in 1985 and in-depth studies were conducted on three species of crayfish, crayfish, and abalone shrimp. The results show that crayfish are most promising. In the 1980s, trials were introduced in many countries including the United States, France, Spain, Japan, and Southeast Asia. Domestically, they were introduced in Guangdong and Hubei provinces in 1992 and the cultivation was successful. Many species in China are now introducing this species and gradually conducting trials and small-scale production.
I. Pond conditions
1. Water: Surface water and groundwater with abundant water sources and excellent water quality are the main conditions for aquaculture. Even during the most severe drought period, water supply must be guaranteed. Water quality is as important as water volume. Chemicals such as heavy metals in water, organic substances such as oil, pesticides, and herbicides should be kept to a minimum. Avoid the high turbidity of water caused by silt, because the turbidity of water will hinder the growth of phytoplankton, and sludge will cause death in the clams of the crayfish. Groundwater and spring water are the best sources of water for shrimp farming. Groundwater has the following advantages: 1. It has a fixed, independent source of water. 2 No pathogens and miscellaneous fish. 2 No pollution. 4 The temperature is relatively stable throughout the year. However, the oxygen, carbon dioxide, sulphide and iron contents in the water must not be too high.
2. Convenient for water intake and drainage: A barrier must be provided at the water inlet to prevent the wild fish from entering the pool. The design of the outlet should be able to control the water level. The overflow discharges the waste water from the bottom of the tank, and the water outlet should also be provided with a barrier to prevent the red squid from escaping. Water channels must also be constructed so that draining water can be drained during fishing. Flowing fresh water can prevent the shrimp pond from being lost due to lack of oxygen.
3. The bottom of the pool: To minimize pool leakage, some growers put gravel in the pool to allow organic sediments to settle. Red shark crawfish can be washed with water after harvest and can be restocked after two days of harvest. In the breeding process, the bottom of the pool must be cleared of silt and the sludge is too thick, which is not conducive to the growth of the shrimp.
4, the pool area: the size of the pool is not very strict specifications, generally 0.2-0.3 hectares (3-5 mu) is appropriate, the pool is rectangular. To maximize the use of natural oxygen, the inner pool wall should have a 1:3 slope with a depth of 1-2 meters.
5. Concealed species: Adult shrimps inhabit the bottom of the pond or clusters crawl in the waters along the pond, and are particularly fond of hiding in aquatic grasses. The pond grows a variety of aquatic organisms, higher aquatic plants, epiphytic algae, aquatic plants, etc. They can be used as feed for shrimp, and it is also a good natural hideaway. Therefore, when choosing a pond, it is necessary to fully consider natural hidden substances. Pond.
Second, water quality
l. Water temperature: Red-snow crayfish are naturally distributed in subtropical and tropical regions. Although it is more resistant to hypothermia and adaptability than Macrobrachium rosenbergii, the experiments show that the long-term survival rate of shrimp at a temperature of 9°C is about 30%. If the temperature rises to 11°C, the shrimp starts to become active and starts feeding. The test shows that the optimum growth temperature is 23-32°C; the critical temperature of the upper limit is 42°C; the lower limit of the 1st critical temperature is 5°C, and the growth is slower than 20°C.
2. Dissolved oxygen: Dissolved oxygen is an important factor influencing the growth of red-handed crayfish. Adequate dissolved oxygen, fresh water, is conducive to the growth of shrimp and feed utilization. It is generally believed that the water-soluble oxygen in the shrimp cultured shrimp should not be lower than 4 mg/l, and the dissolved oxygen in the hatchery nursery should be above 5 mg/l. During the production process, due to sudden changes in the weather and deteriorating water quality resulting in lack of oxygen, red-claw crayfish are often found crawling on the banks. There are great differences in the oxygen consumption of the red crayfish at different life stages, different genders and different physiological conditions. In general, juveniles are higher than adult shrimp; males are higher than females; snail-eating shrimps are higher than non-sustaining shrimps; soft-shelled shrimps are higher than hard-shelled shrimps.
3. PH value and salinity: The pH value of the growth of red-caught crayfish is 6-8. Keeping the appropriate pH is conducive to the decomposition of organic matter in the shrimp pond, promoting the growth of live feeds and the clam shell of the shrimp. Therefore, the pH value of 7.5-8 is appropriate, and the number of predator organisms is small, so it is necessary to regularly apply it during the production process. Lime to adjust the pH of the pool water. According to reports, the peak value of red crab crayfish is 2.4%.
4. Transparency: The water is fresh, and the aquatic plants in the pool are abundant, which is beneficial to the growth of the shrimp. The transparency that is too small is often unfavorable to the growth of the shrimp, or to oxygen deficiency due to excessive oxygen consumption. General transparency should be maintained at about 40 cm.
5. Trinitrogen: Regularly determine the trinitrogen content. If the trinitrogen in the pool is too high, change the water regularly.
Third, feeding and management
1. Seedlings: Seedlings are the key to the development of red-claw crayfish. The juvenile shrimp that leave the mother's body usually have a body length of 0.8 cm. At this time, the survival rate of the shrimp seedlings is relatively low. Therefore, the seedlings with a size of more than 2 cm are generally stocked and the survival rate is relatively high. Generally, the requirements for the shrimp cultured shrimp are as follows:
(1) The specifications are relatively neat, and the seedlings are strong;
(2) strong vitality, sensitive to stimuli;
(3) Shrimp seedlings have strong drought resistance. Generally, if there is a certain degree of humidity, the water can still survive after 2 hours.
(4) From the seedlings of water, the ambient temperature should not be lower than 12°C.
2. Preparation before stocking: The preparation of shrimp before stocking is the key link in shrimp farming. Therefore, the preparation work before the shrimp enters the pool should be sufficient so that the shrimp can have a good ecological environment and abundant feed.
(1) Preparation of aquaculture ponds: Before putting shrimps in ponds, ponds must be carefully cleaned to remove silt and flat bottoms so that the bottom and walls of the pond have good water retention properties and water leakage is minimized. The pool embankment must have a certain slope. Where conditions permit, digging a ditch in the middle of the bottom of the pool or digging a ditch around the bottom of the ditch can be helpful for the cultivation and management of early shrimp seedlings and the convenience of capture.
(2) Clear pond: The clear pond work is a preparatory work that must be done before the red clams are cultivated. The work of clear ponds directly affects the survival rate and aquaculture production of shrimp. The commonly used methods mainly include quicklime and bleached clear ponds.
(3) Influent and fertilizing: After 7-10 days in the clear pond, it is necessary to enter the water. When injecting new water, it is necessary to do a good job of filtering to prevent the wild fish and eggs from entering the pool with water. The fertilizer and water must be taken one week prior to planting, so that the water is rich in plankton and becomes a direct feed for shrimp. The amount of commonly used organic fertilizer is 75-100 kg per acre, so that the pool water to maintain a certain degree of fat. At this time, the water level is shallow. With the deepening of the water, it is necessary to gradually increase the amount of fertilizer. It depends on the color.
(4) Planting water plants: Water plants are one of the main feeds for shrimps. Due to the complex feeding habits of red clam crayfish, animal species, but in the case of insufficient animal feed, they mainly eat grass, such as Vallisneria, and Hydrilla verticillata. , Eichhornia crassipes, water lilies, and philodendrons (water peanuts). Aquatic grasses are also an ideal place for hidden and inhabited shrimps, as well as a good place for shrimps. Raising shrimp in ponds with many aquatic plants has a high survival rate. A further function of aquatic plants is to purify water quality, reduce the body's fatness, precipitate suspended matter, make fresh water, and improve transparency.
3, stocking density: shrimp stocking before going through the test of water, test water, with bottled water, release a few shrimp, after half an hour observation, shrimp normal activity, confirmed that pool water toxicity disappeared before the shrimp Put the seedlings into the pond. Pond farming depends on pond conditions (water depth, area, sediment, etc.), combined with production requirements to determine stocking densities. When the density is too large and growing, the individuals are small at the time of harvest and cannot obtain good yields. When the density is too small, the potential for pond production cannot be exerted. Therefore, the amount of stocking should be determined from the planned yield and the expected survival rate, and at the same time, the individual size and average weight of shrimp should be estimated. According to practical experience, the general formula can be used as follows:
For example, the planned output is 200 kilograms per mu. It is estimated that the shrimps will grow to about 80 grams per year and the survival rate will be 75%. If the aquaculture area is 3 acres, the total stocking capacity will be about 100000.
4. Feed: Feed is the material basis for the growth and development of shrimp. The quality and nutritional value of feed are also one of the important factors that affect the feed coefficient and production cost. Red crabs and shrimps are omnivorous animals. The feed and feeding time and frequency should be further discussed. Generally, they are fed according to the feed and feeding conditions of other shrimps. In the case of intensive culture, artificial feeds are mainly used, and according to their different growth stages, feeds that are suitable for puppies, such as adding some animal feed at a later stage to promote their growth, can also avoid mutual killing. But the farming experience shows. The shrimp's feed is relatively easy to solve (Table 1).
Table of crayfish feed
Natural feed cockroach, miscellaneous fish chips, carrots, grasses, aquatic insects, pig cow dung, shellfish, plant debris
Artificial feed for poultry, fish, shrimp and crab
5. Anti-escape: In extreme cases, such as poor water quality, insufficient dissolved oxygen, etc., there will be a small amount of red crayfish crawling onto the embankment. This will happen both during the winter and during the high temperature evening. Its ability to escape is far inferior to river crabs. Normally, it will still return to the pond. In the breeding process, it usually uses inexpensive membranes on the walls around the shrimp ponds that are 30 cm high. This will prevent them from escaping.
6. Daily management: The main management tasks for adult shrimp farming are feeding feed, aeration and water injection, refurbishment of pond embankment, leakage prevention, escape prevention and observation of temperature, water temperature and growth of shrimp.
(1) Feeding and Feeding: In order to make a reasonable feeding, it is necessary to analyze, adjust and calculate the feeding amount according to the following conditions. The number of feedings is two times in the early stage and the growth period is increased one more time. The feeding time is usually 8 o'clock in the morning, 5 o'clock in the afternoon and 8 o'clock in the evening. The amount of feeding in the daytime is 30% of the total amount of the sunstroke and the amount of feeding in the evening. For the total amount of 70%. It is best to feed the animals at night, such as animal foods such as small fish. When feeding, attention must be paid to: (1) individual shrimp size, measuring body length and body weight of the shrimp every other week, and estimating the survival rate; (2) observing the growth stage, living conditions, and physiological conditions (such as shells and sexual maturation) of the shrimp ); 3 pay attention to the climate, water temperature and water quality; 4 according to the feeding situation to determine the amount of feed; 5 species and quality of feed; 6 the amount of basic feed in the pond.
(2) Changing the water: The purpose of changing the water is to increase the dissolved oxygen, lower the temperature, and stimulate the shrimp shell to accelerate its growth. After the early shrimp seedlings enter the pond, they gradually inject water as the shrimp grows. By the time the shrimp grows, the water is changed according to the following conditions: 1 The seedling density is too high; 2 The pond has too much biomass; 3 The water quality is too strong, deteriorates and Transparency is low; 4 the water temperature is too high, exceeding 32°C; 5 the weather is hot and windless, and shrimp crawls up the dike. The general water change is arranged in the evening as much as possible, and the water exchange volume accounts for about 10% of the total body of water.
(3) Increased concealment: In foreign countries, concealed objects mainly include plastic cards, beer cans, cement pipes, plastic pipes, fiber nets, and old tires. In China, it is mainly broken nets and roots.
(4) Observation of the patrol pond: Sightseeing pond observation is the work that must be done during the culture of red squid crayfish so that problems can be discovered in time and corresponding measures can be taken to accumulate breeding experience. The contents of the patrol pond include: 1 recording climate conditions such as water temperature, rain and wind power; 2 patrol ponds to observe the growth of shrimp shells, deaths, and the vigor of the shrimp on the dykes; 3 observe the water color, because shrimp prefers water quality Living in the environment, and therefore must always observe the transparency of the record of water and water; 4 observe the feeding situation and whether the bottom of the pool becomes dark, and take corresponding measures; 5 observe the individual differences, because the red-claw crayfish fl The difference is more obvious. Therefore, when feeding the feed, the amount of feed must be increased;
(5) Remove enemy predators in time.
In short, shrimp farming must closely focus on several important aspects such as water quality, seedlings, feed, and management, so as to achieve the ideal of stable production and high yield.
I. Pond conditions
1. Water: Surface water and groundwater with abundant water sources and excellent water quality are the main conditions for aquaculture. Even during the most severe drought period, water supply must be guaranteed. Water quality is as important as water volume. Chemicals such as heavy metals in water, organic substances such as oil, pesticides, and herbicides should be kept to a minimum. Avoid the high turbidity of water caused by silt, because the turbidity of water will hinder the growth of phytoplankton, and sludge will cause death in the clams of the crayfish. Groundwater and spring water are the best sources of water for shrimp farming. Groundwater has the following advantages: 1. It has a fixed, independent source of water. 2 No pathogens and miscellaneous fish. 2 No pollution. 4 The temperature is relatively stable throughout the year. However, the oxygen, carbon dioxide, sulphide and iron contents in the water must not be too high.
2. Convenient for water intake and drainage: A barrier must be provided at the water inlet to prevent the wild fish from entering the pool. The design of the outlet should be able to control the water level. The overflow discharges the waste water from the bottom of the tank, and the water outlet should also be provided with a barrier to prevent the red squid from escaping. Water channels must also be constructed so that draining water can be drained during fishing. Flowing fresh water can prevent the shrimp pond from being lost due to lack of oxygen.
3. The bottom of the pool: To minimize pool leakage, some growers put gravel in the pool to allow organic sediments to settle. Red shark crawfish can be washed with water after harvest and can be restocked after two days of harvest. In the breeding process, the bottom of the pool must be cleared of silt and the sludge is too thick, which is not conducive to the growth of the shrimp.
4, the pool area: the size of the pool is not very strict specifications, generally 0.2-0.3 hectares (3-5 mu) is appropriate, the pool is rectangular. To maximize the use of natural oxygen, the inner pool wall should have a 1:3 slope with a depth of 1-2 meters.
5. Concealed species: Adult shrimps inhabit the bottom of the pond or clusters crawl in the waters along the pond, and are particularly fond of hiding in aquatic grasses. The pond grows a variety of aquatic organisms, higher aquatic plants, epiphytic algae, aquatic plants, etc. They can be used as feed for shrimp, and it is also a good natural hideaway. Therefore, when choosing a pond, it is necessary to fully consider natural hidden substances. Pond.
Second, water quality
l. Water temperature: Red-snow crayfish are naturally distributed in subtropical and tropical regions. Although it is more resistant to hypothermia and adaptability than Macrobrachium rosenbergii, the experiments show that the long-term survival rate of shrimp at a temperature of 9°C is about 30%. If the temperature rises to 11°C, the shrimp starts to become active and starts feeding. The test shows that the optimum growth temperature is 23-32°C; the critical temperature of the upper limit is 42°C; the lower limit of the 1st critical temperature is 5°C, and the growth is slower than 20°C.
2. Dissolved oxygen: Dissolved oxygen is an important factor influencing the growth of red-handed crayfish. Adequate dissolved oxygen, fresh water, is conducive to the growth of shrimp and feed utilization. It is generally believed that the water-soluble oxygen in the shrimp cultured shrimp should not be lower than 4 mg/l, and the dissolved oxygen in the hatchery nursery should be above 5 mg/l. During the production process, due to sudden changes in the weather and deteriorating water quality resulting in lack of oxygen, red-claw crayfish are often found crawling on the banks. There are great differences in the oxygen consumption of the red crayfish at different life stages, different genders and different physiological conditions. In general, juveniles are higher than adult shrimp; males are higher than females; snail-eating shrimps are higher than non-sustaining shrimps; soft-shelled shrimps are higher than hard-shelled shrimps.
3. PH value and salinity: The pH value of the growth of red-caught crayfish is 6-8. Keeping the appropriate pH is conducive to the decomposition of organic matter in the shrimp pond, promoting the growth of live feeds and the clam shell of the shrimp. Therefore, the pH value of 7.5-8 is appropriate, and the number of predator organisms is small, so it is necessary to regularly apply it during the production process. Lime to adjust the pH of the pool water. According to reports, the peak value of red crab crayfish is 2.4%.
4. Transparency: The water is fresh, and the aquatic plants in the pool are abundant, which is beneficial to the growth of the shrimp. The transparency that is too small is often unfavorable to the growth of the shrimp, or to oxygen deficiency due to excessive oxygen consumption. General transparency should be maintained at about 40 cm.
5. Trinitrogen: Regularly determine the trinitrogen content. If the trinitrogen in the pool is too high, change the water regularly.
Third, feeding and management
1. Seedlings: Seedlings are the key to the development of red-claw crayfish. The juvenile shrimp that leave the mother's body usually have a body length of 0.8 cm. At this time, the survival rate of the shrimp seedlings is relatively low. Therefore, the seedlings with a size of more than 2 cm are generally stocked and the survival rate is relatively high. Generally, the requirements for the shrimp cultured shrimp are as follows:
(1) The specifications are relatively neat, and the seedlings are strong;
(2) strong vitality, sensitive to stimuli;
(3) Shrimp seedlings have strong drought resistance. Generally, if there is a certain degree of humidity, the water can still survive after 2 hours.
(4) From the seedlings of water, the ambient temperature should not be lower than 12°C.
2. Preparation before stocking: The preparation of shrimp before stocking is the key link in shrimp farming. Therefore, the preparation work before the shrimp enters the pool should be sufficient so that the shrimp can have a good ecological environment and abundant feed.
(1) Preparation of aquaculture ponds: Before putting shrimps in ponds, ponds must be carefully cleaned to remove silt and flat bottoms so that the bottom and walls of the pond have good water retention properties and water leakage is minimized. The pool embankment must have a certain slope. Where conditions permit, digging a ditch in the middle of the bottom of the pool or digging a ditch around the bottom of the ditch can be helpful for the cultivation and management of early shrimp seedlings and the convenience of capture.
(2) Clear pond: The clear pond work is a preparatory work that must be done before the red clams are cultivated. The work of clear ponds directly affects the survival rate and aquaculture production of shrimp. The commonly used methods mainly include quicklime and bleached clear ponds.
(3) Influent and fertilizing: After 7-10 days in the clear pond, it is necessary to enter the water. When injecting new water, it is necessary to do a good job of filtering to prevent the wild fish and eggs from entering the pool with water. The fertilizer and water must be taken one week prior to planting, so that the water is rich in plankton and becomes a direct feed for shrimp. The amount of commonly used organic fertilizer is 75-100 kg per acre, so that the pool water to maintain a certain degree of fat. At this time, the water level is shallow. With the deepening of the water, it is necessary to gradually increase the amount of fertilizer. It depends on the color.
(4) Planting water plants: Water plants are one of the main feeds for shrimps. Due to the complex feeding habits of red clam crayfish, animal species, but in the case of insufficient animal feed, they mainly eat grass, such as Vallisneria, and Hydrilla verticillata. , Eichhornia crassipes, water lilies, and philodendrons (water peanuts). Aquatic grasses are also an ideal place for hidden and inhabited shrimps, as well as a good place for shrimps. Raising shrimp in ponds with many aquatic plants has a high survival rate. A further function of aquatic plants is to purify water quality, reduce the body's fatness, precipitate suspended matter, make fresh water, and improve transparency.
3, stocking density: shrimp stocking before going through the test of water, test water, with bottled water, release a few shrimp, after half an hour observation, shrimp normal activity, confirmed that pool water toxicity disappeared before the shrimp Put the seedlings into the pond. Pond farming depends on pond conditions (water depth, area, sediment, etc.), combined with production requirements to determine stocking densities. When the density is too large and growing, the individuals are small at the time of harvest and cannot obtain good yields. When the density is too small, the potential for pond production cannot be exerted. Therefore, the amount of stocking should be determined from the planned yield and the expected survival rate, and at the same time, the individual size and average weight of shrimp should be estimated. According to practical experience, the general formula can be used as follows:
For example, the planned output is 200 kilograms per mu. It is estimated that the shrimps will grow to about 80 grams per year and the survival rate will be 75%. If the aquaculture area is 3 acres, the total stocking capacity will be about 100000.
4. Feed: Feed is the material basis for the growth and development of shrimp. The quality and nutritional value of feed are also one of the important factors that affect the feed coefficient and production cost. Red crabs and shrimps are omnivorous animals. The feed and feeding time and frequency should be further discussed. Generally, they are fed according to the feed and feeding conditions of other shrimps. In the case of intensive culture, artificial feeds are mainly used, and according to their different growth stages, feeds that are suitable for puppies, such as adding some animal feed at a later stage to promote their growth, can also avoid mutual killing. But the farming experience shows. The shrimp's feed is relatively easy to solve (Table 1).
Table of crayfish feed
Natural feed cockroach, miscellaneous fish chips, carrots, grasses, aquatic insects, pig cow dung, shellfish, plant debris
Artificial feed for poultry, fish, shrimp and crab
5. Anti-escape: In extreme cases, such as poor water quality, insufficient dissolved oxygen, etc., there will be a small amount of red crayfish crawling onto the embankment. This will happen both during the winter and during the high temperature evening. Its ability to escape is far inferior to river crabs. Normally, it will still return to the pond. In the breeding process, it usually uses inexpensive membranes on the walls around the shrimp ponds that are 30 cm high. This will prevent them from escaping.
6. Daily management: The main management tasks for adult shrimp farming are feeding feed, aeration and water injection, refurbishment of pond embankment, leakage prevention, escape prevention and observation of temperature, water temperature and growth of shrimp.
(1) Feeding and Feeding: In order to make a reasonable feeding, it is necessary to analyze, adjust and calculate the feeding amount according to the following conditions. The number of feedings is two times in the early stage and the growth period is increased one more time. The feeding time is usually 8 o'clock in the morning, 5 o'clock in the afternoon and 8 o'clock in the evening. The amount of feeding in the daytime is 30% of the total amount of the sunstroke and the amount of feeding in the evening. For the total amount of 70%. It is best to feed the animals at night, such as animal foods such as small fish. When feeding, attention must be paid to: (1) individual shrimp size, measuring body length and body weight of the shrimp every other week, and estimating the survival rate; (2) observing the growth stage, living conditions, and physiological conditions (such as shells and sexual maturation) of the shrimp ); 3 pay attention to the climate, water temperature and water quality; 4 according to the feeding situation to determine the amount of feed; 5 species and quality of feed; 6 the amount of basic feed in the pond.
(2) Changing the water: The purpose of changing the water is to increase the dissolved oxygen, lower the temperature, and stimulate the shrimp shell to accelerate its growth. After the early shrimp seedlings enter the pond, they gradually inject water as the shrimp grows. By the time the shrimp grows, the water is changed according to the following conditions: 1 The seedling density is too high; 2 The pond has too much biomass; 3 The water quality is too strong, deteriorates and Transparency is low; 4 the water temperature is too high, exceeding 32°C; 5 the weather is hot and windless, and shrimp crawls up the dike. The general water change is arranged in the evening as much as possible, and the water exchange volume accounts for about 10% of the total body of water.
(3) Increased concealment: In foreign countries, concealed objects mainly include plastic cards, beer cans, cement pipes, plastic pipes, fiber nets, and old tires. In China, it is mainly broken nets and roots.
(4) Observation of the patrol pond: Sightseeing pond observation is the work that must be done during the culture of red squid crayfish so that problems can be discovered in time and corresponding measures can be taken to accumulate breeding experience. The contents of the patrol pond include: 1 recording climate conditions such as water temperature, rain and wind power; 2 patrol ponds to observe the growth of shrimp shells, deaths, and the vigor of the shrimp on the dykes; 3 observe the water color, because shrimp prefers water quality Living in the environment, and therefore must always observe the transparency of the record of water and water; 4 observe the feeding situation and whether the bottom of the pool becomes dark, and take corresponding measures; 5 observe the individual differences, because the red-claw crayfish fl The difference is more obvious. Therefore, when feeding the feed, the amount of feed must be increased;
(5) Remove enemy predators in time.
In short, shrimp farming must closely focus on several important aspects such as water quality, seedlings, feed, and management, so as to achieve the ideal of stable production and high yield.
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