Morphological characteristics
The grouper is long and oval in shape with its sides flat and stout. The mouth is large, with a well-developed auxiliary maxilla, with a large number of large canine teeth at the front and bottom jaws, and finely pointed teeth on both sides, which can be lodged inwards. The posterior edge of the front humeral bone is generally serrated, and the lower edge is smooth. The posterior edge of the humeral cap has two rough spines, and the midpoint of the zygomatic bone is long and less in number. The body is finely scaled, the spine of the dorsal fins is connected to the fins, and there are no nicks. There are generally 11 fin spines (rarely 10), 14-18 fins, an anal fin with 3 fin spines, and 8-9 fins. The fin spine is the strongest. Caudal fins rounded, truncated or concave. Pyloric sac 10-20.
Ecological distribution
Grouper is distributed on the coast of the warm waters of various countries in the world. It is a warm-temperate middle-lower fish and mostly lives in the rocky bottom. It often inhabits reefs near the coastal islands and caves or gaps in coral reefs. It is usually nocturnal. He finds food by smell, and hides in caves during the day. Grouper is ferocious, meat-based, like to eat fish, shrimp, crabs, do not like to group, when there is fratricidal hunger. The adaptability to salinity is very wide. It can live within the salinity range of 11-41%. The optimum water temperature is 22-28°C. The appetite decreases below 18°C, and the fish loses its balance under 15°C.
Seed production
Seed cultivation
In addition to Taiwan Province, the current artificial breeding of grouper in China is in the experimental stage. Therefore, the cultured seedlings mainly rely on the capture of natural sea areas. The fishing methods are mainly as follows
Trawling
The rectangular mesh formed by the two-sleeping net and the central sac net is 40 meters long, 3.3 meters high, and 0.7 cm net. The shells, feathers and other objects are used on the tug to frighten the fry. The disadvantage of trawls is that there are more injuries to fry, and the general survival rate is only 70-80%.
Seine fishing
The net is rectangular, generally 10 meters long, 1.5 meters high, 1.0-1.5 cm mesh. The main program is floating, the next stage is sinking, and both ends have a hemp main cable. After the fry was found, it was caught in the wind and the operation was quick and the operation was coordinated. The water was pulled from deep water to shallow water. When fishing, the net should not leave the water to avoid the fish fleeing.
Small trawl fishing
The net has a rectangular shape with a net length of 8-10 meters, a net height of 50-80 cm and a mesh size of 0.4-1.0 cm. Upper and lower support with bamboo poles. During the work, the two dragged forward, stepped in unison, and had agile actions. The top and bottom nets were drawn properly to achieve satisfactory results. After the tidal wave, the counter-tide was rounded forward. When rounding up, keeping the net at a certain depth, too high or too low, will cause the fish to escape.
Pushing net fishing
The net is in a triangle or shape. The mesh is 0.4-1.2 centimeters, and the bottom of the net is 8-10. The two sides of the net are shoved and pushed, and the foot is lowered so as not to be trapped in the mud. This net is operated by one person and is suitable for working in a place where there is a small gutter and a wide area of ​​the beach. Usually, the fish fry 2-3 cm in length is picked up during the rise and low tide.
Breeding technology
Cage culture
(1) Stocking of fingerlings: Fish fingerlings cultured in cages should not be small in size. Large fish species specifications, absolute increase in the rate of meat, fast growth, can shorten the breeding cycle, improve the breeding efficiency of cages. Stocking densities vary depending on environmental conditions and the level of farming techniques. Generally, stockings are 2-3 cm in length and each cage can hold 2,000-3,000 tails. After intensive breeding for 1-2 months, fish stocks that are robust, fast-growing, and invigorating are selected for aquaculture. Each cage can contain 1,000-1,500 fish. Later, with the growth of the fish, it is advisable to divide the box and keep its density at 300 kg or less per cage.
(2) Feeding: Grouper is a carnivorous fish, and it is generally used as a bait. In the juvenile stage, the minced meat machine must be crushed into fish paste before it can be fed. Later, as the size of the fish increases, it can be cut into small pieces or large pieces. When the fish grows up, small individual and mixed shrimps can be fed directly. The amount of bait varies depending on the season and weather conditions. From April to November, the temperature and water temperature are relatively high, which is the main growth period of fish and the most vigorous season for feeding. At this time, the amount of feeding is generally 6-8% of the total fish body weight.
From December to March of the following year, the temperature and temperature of the water are relatively low, and the fish eat less, and sometimes even do not eat. At this time, the amount of bait should be reduced so as not to waste food and pollute the water quality. For each group of 1 kg of common grouper, consume about 7 kg of bait (mixed fish and shrimp).
(3) Replacement of cages: Generally from juvenile fish farming to commercial fish, several cages with different mesh sizes are required. The principle of replacement is that the mesh is constantly increasing, and it is possible to keep the water flowing while avoiding fish. The common seedling stage uses a 0.5 cm mesh cloth. When the fish body grows to 6-8 cm in length, use a net with a mesh of 3 cm. When the fish body grows to a weight of 150-200 g, it is replaced with a net cloth with a mesh size of 5 cm. Replaced the net clothes, use copper sulfate solution to soak, remove attachments, ready for reuse. The method is to use 3-4 kg of copper sulfate, 10-15 liters of formic acid and 400 liters of fresh water, and then put the netcloth in the soak for 2-3 days and then rinse it. In addition, treatment with copper sulphate or bitumen before the use of the netting can reduce the growth of algae and other attachments and reduce management troubles.
(4) Removal of attachments: During the breeding process, the attachments of cages and floats should be promptly removed to prevent the meshes from being blocked and obstructing the flow of water, thus hindering the growth of fish. Clearing method can be used to wash the net wall periodically, but also flushing machine (water gun) to wash the net wall.
(5) Security check: mainly check whether the cage has any loopholes or breakages, and if the frame is firm, etc., find problems and repair it in time.
Disease prevention and treatment
White spot disease
Symptoms and causes: The pathogens are ciliates. The diseased fish have visible white spots on the body surface and fins. Control methods: Put 5-8 ppm of bleaching powder or potassium permanganate in fresh water, soak the diseased fish in water for 2-3 minutes, or soak it with red syrup or quinine hydrochloride. Applicable drugs: bleach, potassium permanganate, red syrup, quinine hydrochloride
Gastrointestinal disease
Symptoms and causes: Pathogens are fungi, mostly brought in by food. The diseased fish has a red stomach or intestine, and bleeding is severe in the event that it eventually dies due to an inflamed ulcer. Control methods: Use antibiotics and sulfa drugs to feed in the bait. The dosage is 20-50 mg of antibiotics per kilogram of diseased fish per day, 100-200 mg of sulfamethoxazole, 2 times per day, feed for 5-7 days. Applicable drugs: antibiotics, sulfa agents.
parasitic disease
Symptoms and causes: The pathogen is a copepod parasite. One is parasitism on the skin of the fish, so that the mucus in the skin is reduced, the appetite is reduced, and then the skin on the side of the body decays, exposing the flesh, the fish gradually weakens and dies; the second is parasitic in the gills, causing the gills to rot. Occurrence of anemia or blockage of silk, preventing the circulation of water and death. Control methods: The former treatment is to soak the diseased fish in fresh water for 3-6 minutes to make the parasites fall off; the latter treatment is to soak the diseased fish in 10% brine for 2-4 minutes. The diseased fish can be soaked in 2-3ppm trichlorfon seawater for 15-20 minutes. Applicable drugs: 10% concentrated saline, trichlorfon.
Tail disease
Causes and Symptoms: Mainly due to a bite in the tail, tearing of the epidermis, and the infiltration of bacteria to expose the capillaries. Diseased fin bases are congested, frog fins, and caudal, pelvic, and pectoral fins are severe. The entire tail fin until the end of the tail rots. Body color subsides, local swelling, ulcers on the body side. Kiss, mouth and lid hyperemia, pale red. Some sick fish eyes have muddy crystals and the eyeballs protrude. Liver, gonads, and fats of internal organs are congested and local necrosis occurs. The abdominal cavity is filled with pale yellow peritoneal fluid. Diseased fish stopped feeding, swimming slowly, feeling dull, swimming in the water surface. Control methods: Dipping with animal tetracycline or oxytetracycline (dissolved in fresh water) at a concentration of 1/5000. Wash for 4 to 10 minutes, continuous washing 2-3 times, there is a certain effect. Applicable drugs: animal tetracycline, oxytetracycline.
Uterus nephrosis
Etiology and Symptoms: There are mainly three types of fin irrefragments, nymph nematodes and nymphs. Diseased fish is thinner. When the body size is large, blood red worms are visible to the naked eye in the fin tissue, especially the pectoral fin, fin membrane, and mandible. The fin borer, 2.4-3.9 cm in length, is bent inside or parallel to the fins. On the inner side of the fin cover, there is a pale red fin nymph nematode with a body length of 1.4-2.6 cm. In the body cavity can be seen in the gonads and other tissues within the brown skeletal fin uterine nematode, the nematode body length 15.6-38.8 cm. Control methods: Applying iodine to treat lesions has a certain effect. Applicable drugs: iodine.
Exophthalmos
Symptoms and causes: Pathogens are fungi. The pupils of the diseased fish were initially enlarged, the eyeballs were prominent and bleeding. In severe cases, the two eyes completely fell off and soon died. Control methods: sulfadiazine and antibiotics (made in Japan) fed into the feed, the effect is very good. The dosage was 200 tablets of sulfadiazine per 100 kg of diseased fish, 20 tablets of antibiotics, and 2 feeds per day for 5 days. Applicable drugs: sulfadiazine, antibiotics (made in Japan).
Harvesting technology
The earthen pond breeding can be captured directly by the nets, seine nets, or after the pool water is drained; the net cage culture can use the cheat net to capture or pull up the hanging cable at the bottom of the cage, unlock the ropes of the cage, and pull the cages. After catching up, lift the box from one end and fly the fish to the corner. Then catch it with a cheat sheet.
The grouper is long and oval in shape with its sides flat and stout. The mouth is large, with a well-developed auxiliary maxilla, with a large number of large canine teeth at the front and bottom jaws, and finely pointed teeth on both sides, which can be lodged inwards. The posterior edge of the front humeral bone is generally serrated, and the lower edge is smooth. The posterior edge of the humeral cap has two rough spines, and the midpoint of the zygomatic bone is long and less in number. The body is finely scaled, the spine of the dorsal fins is connected to the fins, and there are no nicks. There are generally 11 fin spines (rarely 10), 14-18 fins, an anal fin with 3 fin spines, and 8-9 fins. The fin spine is the strongest. Caudal fins rounded, truncated or concave. Pyloric sac 10-20.
Ecological distribution
Grouper is distributed on the coast of the warm waters of various countries in the world. It is a warm-temperate middle-lower fish and mostly lives in the rocky bottom. It often inhabits reefs near the coastal islands and caves or gaps in coral reefs. It is usually nocturnal. He finds food by smell, and hides in caves during the day. Grouper is ferocious, meat-based, like to eat fish, shrimp, crabs, do not like to group, when there is fratricidal hunger. The adaptability to salinity is very wide. It can live within the salinity range of 11-41%. The optimum water temperature is 22-28°C. The appetite decreases below 18°C, and the fish loses its balance under 15°C.
Seed production
Seed cultivation
In addition to Taiwan Province, the current artificial breeding of grouper in China is in the experimental stage. Therefore, the cultured seedlings mainly rely on the capture of natural sea areas. The fishing methods are mainly as follows
Trawling
The rectangular mesh formed by the two-sleeping net and the central sac net is 40 meters long, 3.3 meters high, and 0.7 cm net. The shells, feathers and other objects are used on the tug to frighten the fry. The disadvantage of trawls is that there are more injuries to fry, and the general survival rate is only 70-80%.
Seine fishing
The net is rectangular, generally 10 meters long, 1.5 meters high, 1.0-1.5 cm mesh. The main program is floating, the next stage is sinking, and both ends have a hemp main cable. After the fry was found, it was caught in the wind and the operation was quick and the operation was coordinated. The water was pulled from deep water to shallow water. When fishing, the net should not leave the water to avoid the fish fleeing.
Small trawl fishing
The net has a rectangular shape with a net length of 8-10 meters, a net height of 50-80 cm and a mesh size of 0.4-1.0 cm. Upper and lower support with bamboo poles. During the work, the two dragged forward, stepped in unison, and had agile actions. The top and bottom nets were drawn properly to achieve satisfactory results. After the tidal wave, the counter-tide was rounded forward. When rounding up, keeping the net at a certain depth, too high or too low, will cause the fish to escape.
Pushing net fishing
The net is in a triangle or shape. The mesh is 0.4-1.2 centimeters, and the bottom of the net is 8-10. The two sides of the net are shoved and pushed, and the foot is lowered so as not to be trapped in the mud. This net is operated by one person and is suitable for working in a place where there is a small gutter and a wide area of ​​the beach. Usually, the fish fry 2-3 cm in length is picked up during the rise and low tide.
Breeding technology
Cage culture
(1) Stocking of fingerlings: Fish fingerlings cultured in cages should not be small in size. Large fish species specifications, absolute increase in the rate of meat, fast growth, can shorten the breeding cycle, improve the breeding efficiency of cages. Stocking densities vary depending on environmental conditions and the level of farming techniques. Generally, stockings are 2-3 cm in length and each cage can hold 2,000-3,000 tails. After intensive breeding for 1-2 months, fish stocks that are robust, fast-growing, and invigorating are selected for aquaculture. Each cage can contain 1,000-1,500 fish. Later, with the growth of the fish, it is advisable to divide the box and keep its density at 300 kg or less per cage.
(2) Feeding: Grouper is a carnivorous fish, and it is generally used as a bait. In the juvenile stage, the minced meat machine must be crushed into fish paste before it can be fed. Later, as the size of the fish increases, it can be cut into small pieces or large pieces. When the fish grows up, small individual and mixed shrimps can be fed directly. The amount of bait varies depending on the season and weather conditions. From April to November, the temperature and water temperature are relatively high, which is the main growth period of fish and the most vigorous season for feeding. At this time, the amount of feeding is generally 6-8% of the total fish body weight.
From December to March of the following year, the temperature and temperature of the water are relatively low, and the fish eat less, and sometimes even do not eat. At this time, the amount of bait should be reduced so as not to waste food and pollute the water quality. For each group of 1 kg of common grouper, consume about 7 kg of bait (mixed fish and shrimp).
(3) Replacement of cages: Generally from juvenile fish farming to commercial fish, several cages with different mesh sizes are required. The principle of replacement is that the mesh is constantly increasing, and it is possible to keep the water flowing while avoiding fish. The common seedling stage uses a 0.5 cm mesh cloth. When the fish body grows to 6-8 cm in length, use a net with a mesh of 3 cm. When the fish body grows to a weight of 150-200 g, it is replaced with a net cloth with a mesh size of 5 cm. Replaced the net clothes, use copper sulfate solution to soak, remove attachments, ready for reuse. The method is to use 3-4 kg of copper sulfate, 10-15 liters of formic acid and 400 liters of fresh water, and then put the netcloth in the soak for 2-3 days and then rinse it. In addition, treatment with copper sulphate or bitumen before the use of the netting can reduce the growth of algae and other attachments and reduce management troubles.
(4) Removal of attachments: During the breeding process, the attachments of cages and floats should be promptly removed to prevent the meshes from being blocked and obstructing the flow of water, thus hindering the growth of fish. Clearing method can be used to wash the net wall periodically, but also flushing machine (water gun) to wash the net wall.
(5) Security check: mainly check whether the cage has any loopholes or breakages, and if the frame is firm, etc., find problems and repair it in time.
Disease prevention and treatment
White spot disease
Symptoms and causes: The pathogens are ciliates. The diseased fish have visible white spots on the body surface and fins. Control methods: Put 5-8 ppm of bleaching powder or potassium permanganate in fresh water, soak the diseased fish in water for 2-3 minutes, or soak it with red syrup or quinine hydrochloride. Applicable drugs: bleach, potassium permanganate, red syrup, quinine hydrochloride
Gastrointestinal disease
Symptoms and causes: Pathogens are fungi, mostly brought in by food. The diseased fish has a red stomach or intestine, and bleeding is severe in the event that it eventually dies due to an inflamed ulcer. Control methods: Use antibiotics and sulfa drugs to feed in the bait. The dosage is 20-50 mg of antibiotics per kilogram of diseased fish per day, 100-200 mg of sulfamethoxazole, 2 times per day, feed for 5-7 days. Applicable drugs: antibiotics, sulfa agents.
parasitic disease
Symptoms and causes: The pathogen is a copepod parasite. One is parasitism on the skin of the fish, so that the mucus in the skin is reduced, the appetite is reduced, and then the skin on the side of the body decays, exposing the flesh, the fish gradually weakens and dies; the second is parasitic in the gills, causing the gills to rot. Occurrence of anemia or blockage of silk, preventing the circulation of water and death. Control methods: The former treatment is to soak the diseased fish in fresh water for 3-6 minutes to make the parasites fall off; the latter treatment is to soak the diseased fish in 10% brine for 2-4 minutes. The diseased fish can be soaked in 2-3ppm trichlorfon seawater for 15-20 minutes. Applicable drugs: 10% concentrated saline, trichlorfon.
Tail disease
Causes and Symptoms: Mainly due to a bite in the tail, tearing of the epidermis, and the infiltration of bacteria to expose the capillaries. Diseased fin bases are congested, frog fins, and caudal, pelvic, and pectoral fins are severe. The entire tail fin until the end of the tail rots. Body color subsides, local swelling, ulcers on the body side. Kiss, mouth and lid hyperemia, pale red. Some sick fish eyes have muddy crystals and the eyeballs protrude. Liver, gonads, and fats of internal organs are congested and local necrosis occurs. The abdominal cavity is filled with pale yellow peritoneal fluid. Diseased fish stopped feeding, swimming slowly, feeling dull, swimming in the water surface. Control methods: Dipping with animal tetracycline or oxytetracycline (dissolved in fresh water) at a concentration of 1/5000. Wash for 4 to 10 minutes, continuous washing 2-3 times, there is a certain effect. Applicable drugs: animal tetracycline, oxytetracycline.
Uterus nephrosis
Etiology and Symptoms: There are mainly three types of fin irrefragments, nymph nematodes and nymphs. Diseased fish is thinner. When the body size is large, blood red worms are visible to the naked eye in the fin tissue, especially the pectoral fin, fin membrane, and mandible. The fin borer, 2.4-3.9 cm in length, is bent inside or parallel to the fins. On the inner side of the fin cover, there is a pale red fin nymph nematode with a body length of 1.4-2.6 cm. In the body cavity can be seen in the gonads and other tissues within the brown skeletal fin uterine nematode, the nematode body length 15.6-38.8 cm. Control methods: Applying iodine to treat lesions has a certain effect. Applicable drugs: iodine.
Exophthalmos
Symptoms and causes: Pathogens are fungi. The pupils of the diseased fish were initially enlarged, the eyeballs were prominent and bleeding. In severe cases, the two eyes completely fell off and soon died. Control methods: sulfadiazine and antibiotics (made in Japan) fed into the feed, the effect is very good. The dosage was 200 tablets of sulfadiazine per 100 kg of diseased fish, 20 tablets of antibiotics, and 2 feeds per day for 5 days. Applicable drugs: sulfadiazine, antibiotics (made in Japan).
Harvesting technology
The earthen pond breeding can be captured directly by the nets, seine nets, or after the pool water is drained; the net cage culture can use the cheat net to capture or pull up the hanging cable at the bottom of the cage, unlock the ropes of the cage, and pull the cages. After catching up, lift the box from one end and fly the fish to the corner. Then catch it with a cheat sheet.
Garden Gloves,Nitrile Glove,Latex Gloves
Fenghua Jade Motor Co., Ltd. , http://www.xwgloves.com