1. Artificial harbors will be built by artificially digging trenches and constructing harbors at selected locations, constructing embankments, building gates, reclaiming beaches, and constructing artificial fish breeding harbors, so that unproductive wasteland wasteland will be transformed into productive fish ports.
1. The embankment will be built around the perimeter of the harbor according to the topography. The height of the embankment should exceed 1m above the maximum tidal level. The width of the embankment depends on the specific needs, but it should not be less than 1 meter at least. The slope is 15 degrees to 70 degrees so as to ensure the water level in the harbor and prevent the escape of fish and shrimp.
2. Digging trenches and digging trenches are often limited to manpower and material resources and cannot be dug, so rational layout is required. Excavation of a number of horizontal and horizontal water channels, on the one hand, is used to induce tides and seedlings, and on the other hand it is to store enough water in the harbor to create suitable habitats for fish and shrimp and migration and growth. The depth and width of the ditch may vary depending on whether the terrain is high or low. Drainage ditch is generally divided into four types: The center ditch faces the gate and induces tides and nano-seedlings. It is the main channel for fish and shrimp seedlings to enter Hong Kong. The water surface should be wide and the water should be deep. The width is generally 6 to 7 meters, and the depth is 1.5 to 2 meters. The Qingshuigou is parallel to the central ditch and is located in the center of the port. The ditch is deep and clear, with a width of 3 to 4 meters and a depth of 1.5 to 2 meters. The water surface is stable and the water temperature is relatively constant. It is a place where fish and shrimps are inhabited, grown and sheltered in the hot season. The ditch is a small ditch which is separated from the center ditch to both sides. The ditch is narrow and amorphous. It is a channel for fish and shrimps to swim, a beach for bait, and activities; the edge ditch surrounds the ditch around the fish port and is used to discharge Water, adjust the amount of water. The center ditch and the edge ditch should have a certain slope in order to allow water intake and drainage.
3. Set gates for large, medium and small gates. The gate is also called a tidal lock. The water source in the port is open, the terrain is low, and it is near the end of the river in the center ditch, so that it can be used to introduce tidal water fish and shrimp seedlings. Zhongzha is also called the drought gate. It is located in a high-lying area in the port. It is used to introduce river water after subcultivation to regulate water quality and water volume in the port. It is generally 1.5 meters high and 1.5 meters to 2 meters wide. The small gate, also known as the reverse floodgate or the floodgate, is 1 meter high and 1 meter wide. It is built at the edge of the edge of the trench and has a low topography. It is connected to the edge trench and uses it to exclude the water in the harbor and to introduce new water so that the gate can continue to grow. , adjust water quality, increase water fertility. In order to increase the amount of sodium seedlings at the seedling stage, some have added a gate outside the small gates to carry out double-gate flooding. In order to produce seedlings and prawns in production, a fish gate with a size similar to the middle is set in the lower part of the Qingshuigou at the lowest point in the territory. It is called a flow foil gate, and it is equipped with flow foil outside the gate.
4. The beach has a large area and cannot be fully excavated. There is a wide shallow bank outside the ditch. After the tide, water will accumulate and become a place for fish and shrimp feeding and activities. This is a “grazing farm†for fish and shrimp. . If human resources are allowed, it is best to clear the beach and create a better ranch when building a port.
5. Na Miao Because of the strong seasonality of brackish water culture, no matter whether it is a natural harbor or an artificial harbor, from napping to harvesting, the general production cycle is only 4 to 4 and a half months. It must be fully prepared and planned in advance. . Before the end of April, a full-scale inspection of Hong Kong facilities will be conducted to conduct a drift in Qinggang. When the tide rises, all the gates will be lifted, the water will be discharged into the harbor, and the water will be drained 3 to 4 times. The salinity and humus will be stored in the harbour. When the gate drains, it will scramble the large and small ditches. The induction of fish and shrimps into Hong Kong is a highly technical work. It is necessary to have the skills to operate the gate to obtain better results. From Mang to Xiaoshu is the period of sub-seedling, and fish and shrimps come into Hong Kong with the trend. Na Miao can be divided into sluice and natiao, that is, when flood tides are raised, water flows into the port, and fish and shrimp seedlings flow into the harbour downstream. At this time, the flow velocity must be greater than the speed of the fry to avoid the inclusion of fish and shrimp. Miao escaped. In mid-naturday, the number of fish and shrimp in the harbor increased and gradually grew. Swimming ability was also increased. When the stunner was raised again, the water level outside the gate was higher than the water level in the harbor by more than 7 cm to ensure that fish and shrimp would not escape. In the later stage of the seedlings, the water level in the gate should be higher than 10 cm to lift the gate. At the same time, in the inside of the gate, octagons are inserted to reduce the possibility of escape of fish and shrimp. The opening size of the splayed foil should be proportional to the flow rate of the influent. A small gate induces seedlings. When the tide ebbs, the gate is closed, and the small gate is raised, so that the clear water flows out of the port, and the temperature of the outflowing water is high, which will facilitate the flow of the barracuda on the top and introduce the seedlings into the ditch outside the small gate. Some fish fry migrated back into Hong Kong and some fish fry concentrated in the outer ditch. When the tide rises to a level similar to the water level in the harbor, the flow rate of the water discharged from the small gate will slow down. At this time, all the small gates will be lifted, and the fry can all enter the port from the gate. Then close the small gate. Since the barracuda has the tendency of reflux and thermophilicity, the number of small gates often exceeds the threshold at the time of the Nasal fish fry.
II. Aquaculture Management During the breeding period, the water quality, water temperature, and water volume in the port must be adjusted to suit the growth of fish and shrimp. The adjustment of water quality in the port is the main management work for the port culture. Regular water changes can maintain good water quality, while the exchange of fresh water can bring in live biological feed and increase the fertility of the water. The content of phosphate in Hong Kong is one of the main conditions that determine water quality. The river water contains sufficient phosphates. After the closure, the phosphorus content in the harbor gradually decreases. When it drops below 3 mg/L to 4 mg/L, it will affect the growth of swimming organisms. Part of the river water. Fertilization is a measure to increase the water quality by increasing the concentration of phosphorus, nitrogen, and other substances in Hong Kong. Fermented human and animal manure is deposited in shallow water in the harbor or put into the basket and put into the ditch. After a few days, plankton can multiply, which is a Effective measures, during the entire breeding period, the water quality in the port remains fresh and fertile, pH 7.6 to 8.5, specific gravity 1.008 to 1.010, dissolved oxygen 5 mg/L to 7 mg/L, and nitrogen content 4 mg/L. 5 mg/L, phosphorus content 0.4 mg/L ~ 0.8 mg/L, ideal for the growth of fish and shrimp. During the breeding period of more than four months, during the rainy season, we must pay attention to flood prevention, do a good job of repairing dikes in advance, and repair the dykes.
Third, the harvest
The harvest season generally should not be later than the white dew, because the weather after the white dew is changeable, fish and shrimp activities are slow and should not be concentrated. In cold weather, fish could not be caught, fish and shrimp could easily be frozen in the harbor, causing difficulties in fishing and causing losses. Common fish harvesters have flow foils, sleeves and other nets. The foil is made of two layers of clam-shell foil and is made into a braided fishing gear. The bottom layer is coarse and thin, and the upper layer is fine. One end of the opening is placed at the gate of the flow foil facing the water source. The flow foil should be placed on a wooden frame that has been plaited in advance with wooden pegs. When the dike is drained, fish and shrimp flow into the foil with the water. This fishing tackle mainly catches barracuda and white shrimp in the current year. Xuan Xuan, also known as “tidal†and “ecstasyâ€, is required to be replaced with sleeve rotation when the water in the port gradually fades and fish and shrimp cannot be re-foiled. This fishery method consists of more than ten pieces of foil and is set at the mouth of the Qingshuigou. First, a small slot is inserted into the mud with a lead plate. When the fish gate is opened during production, the tide will enter the port. When the fish meets the fresh water flow, it will turn against the water. At this time, we must pay attention to controlling the size and urgency of the tide's entry, and adjust it until it is dry and clean. This type of fishing tackle mainly captures barracuda and a few fish and shrimp. Other digging trenches, pits, and the use of conical nets, screens, and spinning nets on gates are also effective fishing gear fishing methods.
IV. Pond culture
There are two forms, one is mainly freshwater fish, mixed with about 10% to 20% of barracuda, and the other is barracuda, which is a mixed freshwater fish. The former farming form has been widely adopted and has good economic benefits; the latter farming form is not popular because of its low yield and low income.
Barracuda staple benthic diatoms and organic debris, mixed with the family fish is not eating, but also use grass carp feces as bait. In the adult fish stage, in addition to feeding certain food baits under the conditions, manure, green manure, or treated sewage and fertilizer water can achieve good production results. In general, the perennial mussel polyculture contains 10% to 20% of the barracuda seedlings or 100 to 150 tails, which can grow to 300 to 400 grams at the end of the year. Without increasing feeding or affecting the yield of other farmed fish, the average yield can increase by 25 kg to 75 kg. The polyculture ratio of 250 kilograms per mu is as follows: 200 species of 1 species of barracuda, 100 species of 200 species of pike species, 100 species of white pike species, 50 species of carp species, and 450 pieces of tilapia; The polyculture ratio of 500 kilograms includes 300 fishes of 1 year old barracuda, 500 fishes of 2 age barracudas, 240 fishes of white carp species, 150 fish carp species, 150 carp fish species and 40 carp fish species.
V. Sea fish and shrimp polyculture
Diversification and nesting of fish in shrimp ponds can increase shrimp pond production and economic efficiency. Fish suitable for polyculture in shrimp ponds are mainly shuttles, catfish and tilapia. In the shrimp pond, polyculture and nesting of barracuda can increase 25 kg of barracuda per acre without increasing the amount of feed and without affecting shrimp production. However, it is generally necessary to raise the barracuda seedlings within 4 cm to 5 cm above the shrimp pond. The specifications are about 10 cm, and 100 to 200 tails per mu.
Sixth, Yantian farming
That is, "salt seed" breeding. Using salt ponds to raise shrimps, barracudas account for 40% to 60% of the production in such aquaculture. Yantian farming does not need to spend money to build facilities and excavate fish ponds. Therefore, the cost is low and it is easy to promote. However, the contradiction between water and salt production on fishery and salt production is difficult to solve.
VII. Disease Prevention
1. Oriental pupa has a high infection rate for barracuda. Oriental cockroach is a kind of copepod that parasitizes in seawater, but it is not suitable for brackish water. If it is found in high-salinity waters, freshwater can be introduced to reduce salinity, and live fish in the brackish water will fall off and die. In addition, polychaete larvae, originally the main diet of shrimp, but in the summer when breeding too much will drill into the cavity of the barracuda fish, intensive in the daytime, the shape of the fly, causing the mullet to die of suffocation. This pest often appears in the harbor.
2. Chrysosporium gigantea is currently the most harmful disease to barracuda species and adult fish. If a small amount of chlorella is found in the fish pond, the entire pool of mullet can be destroyed in a few days. Chrysosporium glaucoides is a typical saltwater dinoflagellate. Occurrence of the pond shows the small rhizomes of Physalospora triticina. The cell density in the pool can reach 8105/ml.
Treatment can be used (2 ~ 3) 10-6 concentration of copper sulfate or (10 ~ 15) 10-6 concentration of liquid ammonia for the whole pool spray, spray with the whole yellow mud water also has good results.
3. Hydromycosis and chytridiomyces are also known as skin mildew, commonly known as "white disease", and the incidence of disease is high in the spring and summer, mainly due to bruising and scale-infestation during fishing, artificial breeding and other operations. Caused by infection, the director of villous white mold hyphae, sick fish loss of appetite, slow action, gradually thin until death.
Treatment methods should be carefully handled to avoid touching the fish body. Apply red mercury or gentian violet on scales off and apply Vaseline, and it is best to keep the pool water flowing. If the fish has been infected with water mold, 0.1% potassium permanganate solution can be used to cure the fish for 5 minutes to 10 minutes can achieve a certain effect.
The chytrid fungus mainly infects the egg during the hatching of the fertilized egg. Therefore, when hatching, the dead eggs should be promptly removed to deteriorate the waterproof quality, and replace the new water with antibiotics to suppress the growth of microorganisms.
1. The embankment will be built around the perimeter of the harbor according to the topography. The height of the embankment should exceed 1m above the maximum tidal level. The width of the embankment depends on the specific needs, but it should not be less than 1 meter at least. The slope is 15 degrees to 70 degrees so as to ensure the water level in the harbor and prevent the escape of fish and shrimp.
2. Digging trenches and digging trenches are often limited to manpower and material resources and cannot be dug, so rational layout is required. Excavation of a number of horizontal and horizontal water channels, on the one hand, is used to induce tides and seedlings, and on the other hand it is to store enough water in the harbor to create suitable habitats for fish and shrimp and migration and growth. The depth and width of the ditch may vary depending on whether the terrain is high or low. Drainage ditch is generally divided into four types: The center ditch faces the gate and induces tides and nano-seedlings. It is the main channel for fish and shrimp seedlings to enter Hong Kong. The water surface should be wide and the water should be deep. The width is generally 6 to 7 meters, and the depth is 1.5 to 2 meters. The Qingshuigou is parallel to the central ditch and is located in the center of the port. The ditch is deep and clear, with a width of 3 to 4 meters and a depth of 1.5 to 2 meters. The water surface is stable and the water temperature is relatively constant. It is a place where fish and shrimps are inhabited, grown and sheltered in the hot season. The ditch is a small ditch which is separated from the center ditch to both sides. The ditch is narrow and amorphous. It is a channel for fish and shrimps to swim, a beach for bait, and activities; the edge ditch surrounds the ditch around the fish port and is used to discharge Water, adjust the amount of water. The center ditch and the edge ditch should have a certain slope in order to allow water intake and drainage.
3. Set gates for large, medium and small gates. The gate is also called a tidal lock. The water source in the port is open, the terrain is low, and it is near the end of the river in the center ditch, so that it can be used to introduce tidal water fish and shrimp seedlings. Zhongzha is also called the drought gate. It is located in a high-lying area in the port. It is used to introduce river water after subcultivation to regulate water quality and water volume in the port. It is generally 1.5 meters high and 1.5 meters to 2 meters wide. The small gate, also known as the reverse floodgate or the floodgate, is 1 meter high and 1 meter wide. It is built at the edge of the edge of the trench and has a low topography. It is connected to the edge trench and uses it to exclude the water in the harbor and to introduce new water so that the gate can continue to grow. , adjust water quality, increase water fertility. In order to increase the amount of sodium seedlings at the seedling stage, some have added a gate outside the small gates to carry out double-gate flooding. In order to produce seedlings and prawns in production, a fish gate with a size similar to the middle is set in the lower part of the Qingshuigou at the lowest point in the territory. It is called a flow foil gate, and it is equipped with flow foil outside the gate.
4. The beach has a large area and cannot be fully excavated. There is a wide shallow bank outside the ditch. After the tide, water will accumulate and become a place for fish and shrimp feeding and activities. This is a “grazing farm†for fish and shrimp. . If human resources are allowed, it is best to clear the beach and create a better ranch when building a port.
5. Na Miao Because of the strong seasonality of brackish water culture, no matter whether it is a natural harbor or an artificial harbor, from napping to harvesting, the general production cycle is only 4 to 4 and a half months. It must be fully prepared and planned in advance. . Before the end of April, a full-scale inspection of Hong Kong facilities will be conducted to conduct a drift in Qinggang. When the tide rises, all the gates will be lifted, the water will be discharged into the harbor, and the water will be drained 3 to 4 times. The salinity and humus will be stored in the harbour. When the gate drains, it will scramble the large and small ditches. The induction of fish and shrimps into Hong Kong is a highly technical work. It is necessary to have the skills to operate the gate to obtain better results. From Mang to Xiaoshu is the period of sub-seedling, and fish and shrimps come into Hong Kong with the trend. Na Miao can be divided into sluice and natiao, that is, when flood tides are raised, water flows into the port, and fish and shrimp seedlings flow into the harbour downstream. At this time, the flow velocity must be greater than the speed of the fry to avoid the inclusion of fish and shrimp. Miao escaped. In mid-naturday, the number of fish and shrimp in the harbor increased and gradually grew. Swimming ability was also increased. When the stunner was raised again, the water level outside the gate was higher than the water level in the harbor by more than 7 cm to ensure that fish and shrimp would not escape. In the later stage of the seedlings, the water level in the gate should be higher than 10 cm to lift the gate. At the same time, in the inside of the gate, octagons are inserted to reduce the possibility of escape of fish and shrimp. The opening size of the splayed foil should be proportional to the flow rate of the influent. A small gate induces seedlings. When the tide ebbs, the gate is closed, and the small gate is raised, so that the clear water flows out of the port, and the temperature of the outflowing water is high, which will facilitate the flow of the barracuda on the top and introduce the seedlings into the ditch outside the small gate. Some fish fry migrated back into Hong Kong and some fish fry concentrated in the outer ditch. When the tide rises to a level similar to the water level in the harbor, the flow rate of the water discharged from the small gate will slow down. At this time, all the small gates will be lifted, and the fry can all enter the port from the gate. Then close the small gate. Since the barracuda has the tendency of reflux and thermophilicity, the number of small gates often exceeds the threshold at the time of the Nasal fish fry.
II. Aquaculture Management During the breeding period, the water quality, water temperature, and water volume in the port must be adjusted to suit the growth of fish and shrimp. The adjustment of water quality in the port is the main management work for the port culture. Regular water changes can maintain good water quality, while the exchange of fresh water can bring in live biological feed and increase the fertility of the water. The content of phosphate in Hong Kong is one of the main conditions that determine water quality. The river water contains sufficient phosphates. After the closure, the phosphorus content in the harbor gradually decreases. When it drops below 3 mg/L to 4 mg/L, it will affect the growth of swimming organisms. Part of the river water. Fertilization is a measure to increase the water quality by increasing the concentration of phosphorus, nitrogen, and other substances in Hong Kong. Fermented human and animal manure is deposited in shallow water in the harbor or put into the basket and put into the ditch. After a few days, plankton can multiply, which is a Effective measures, during the entire breeding period, the water quality in the port remains fresh and fertile, pH 7.6 to 8.5, specific gravity 1.008 to 1.010, dissolved oxygen 5 mg/L to 7 mg/L, and nitrogen content 4 mg/L. 5 mg/L, phosphorus content 0.4 mg/L ~ 0.8 mg/L, ideal for the growth of fish and shrimp. During the breeding period of more than four months, during the rainy season, we must pay attention to flood prevention, do a good job of repairing dikes in advance, and repair the dykes.
Third, the harvest
The harvest season generally should not be later than the white dew, because the weather after the white dew is changeable, fish and shrimp activities are slow and should not be concentrated. In cold weather, fish could not be caught, fish and shrimp could easily be frozen in the harbor, causing difficulties in fishing and causing losses. Common fish harvesters have flow foils, sleeves and other nets. The foil is made of two layers of clam-shell foil and is made into a braided fishing gear. The bottom layer is coarse and thin, and the upper layer is fine. One end of the opening is placed at the gate of the flow foil facing the water source. The flow foil should be placed on a wooden frame that has been plaited in advance with wooden pegs. When the dike is drained, fish and shrimp flow into the foil with the water. This fishing tackle mainly catches barracuda and white shrimp in the current year. Xuan Xuan, also known as “tidal†and “ecstasyâ€, is required to be replaced with sleeve rotation when the water in the port gradually fades and fish and shrimp cannot be re-foiled. This fishery method consists of more than ten pieces of foil and is set at the mouth of the Qingshuigou. First, a small slot is inserted into the mud with a lead plate. When the fish gate is opened during production, the tide will enter the port. When the fish meets the fresh water flow, it will turn against the water. At this time, we must pay attention to controlling the size and urgency of the tide's entry, and adjust it until it is dry and clean. This type of fishing tackle mainly captures barracuda and a few fish and shrimp. Other digging trenches, pits, and the use of conical nets, screens, and spinning nets on gates are also effective fishing gear fishing methods.
IV. Pond culture
There are two forms, one is mainly freshwater fish, mixed with about 10% to 20% of barracuda, and the other is barracuda, which is a mixed freshwater fish. The former farming form has been widely adopted and has good economic benefits; the latter farming form is not popular because of its low yield and low income.
Barracuda staple benthic diatoms and organic debris, mixed with the family fish is not eating, but also use grass carp feces as bait. In the adult fish stage, in addition to feeding certain food baits under the conditions, manure, green manure, or treated sewage and fertilizer water can achieve good production results. In general, the perennial mussel polyculture contains 10% to 20% of the barracuda seedlings or 100 to 150 tails, which can grow to 300 to 400 grams at the end of the year. Without increasing feeding or affecting the yield of other farmed fish, the average yield can increase by 25 kg to 75 kg. The polyculture ratio of 250 kilograms per mu is as follows: 200 species of 1 species of barracuda, 100 species of 200 species of pike species, 100 species of white pike species, 50 species of carp species, and 450 pieces of tilapia; The polyculture ratio of 500 kilograms includes 300 fishes of 1 year old barracuda, 500 fishes of 2 age barracudas, 240 fishes of white carp species, 150 fish carp species, 150 carp fish species and 40 carp fish species.
V. Sea fish and shrimp polyculture
Diversification and nesting of fish in shrimp ponds can increase shrimp pond production and economic efficiency. Fish suitable for polyculture in shrimp ponds are mainly shuttles, catfish and tilapia. In the shrimp pond, polyculture and nesting of barracuda can increase 25 kg of barracuda per acre without increasing the amount of feed and without affecting shrimp production. However, it is generally necessary to raise the barracuda seedlings within 4 cm to 5 cm above the shrimp pond. The specifications are about 10 cm, and 100 to 200 tails per mu.
Sixth, Yantian farming
That is, "salt seed" breeding. Using salt ponds to raise shrimps, barracudas account for 40% to 60% of the production in such aquaculture. Yantian farming does not need to spend money to build facilities and excavate fish ponds. Therefore, the cost is low and it is easy to promote. However, the contradiction between water and salt production on fishery and salt production is difficult to solve.
VII. Disease Prevention
1. Oriental pupa has a high infection rate for barracuda. Oriental cockroach is a kind of copepod that parasitizes in seawater, but it is not suitable for brackish water. If it is found in high-salinity waters, freshwater can be introduced to reduce salinity, and live fish in the brackish water will fall off and die. In addition, polychaete larvae, originally the main diet of shrimp, but in the summer when breeding too much will drill into the cavity of the barracuda fish, intensive in the daytime, the shape of the fly, causing the mullet to die of suffocation. This pest often appears in the harbor.
2. Chrysosporium gigantea is currently the most harmful disease to barracuda species and adult fish. If a small amount of chlorella is found in the fish pond, the entire pool of mullet can be destroyed in a few days. Chrysosporium glaucoides is a typical saltwater dinoflagellate. Occurrence of the pond shows the small rhizomes of Physalospora triticina. The cell density in the pool can reach 8105/ml.
Treatment can be used (2 ~ 3) 10-6 concentration of copper sulfate or (10 ~ 15) 10-6 concentration of liquid ammonia for the whole pool spray, spray with the whole yellow mud water also has good results.
3. Hydromycosis and chytridiomyces are also known as skin mildew, commonly known as "white disease", and the incidence of disease is high in the spring and summer, mainly due to bruising and scale-infestation during fishing, artificial breeding and other operations. Caused by infection, the director of villous white mold hyphae, sick fish loss of appetite, slow action, gradually thin until death.
Treatment methods should be carefully handled to avoid touching the fish body. Apply red mercury or gentian violet on scales off and apply Vaseline, and it is best to keep the pool water flowing. If the fish has been infected with water mold, 0.1% potassium permanganate solution can be used to cure the fish for 5 minutes to 10 minutes can achieve a certain effect.
The chytrid fungus mainly infects the egg during the hatching of the fertilized egg. Therefore, when hatching, the dead eggs should be promptly removed to deteriorate the waterproof quality, and replace the new water with antibiotics to suppress the growth of microorganisms.
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