In recent years, the successful upbringing of flounder, such as gingiva, turbot, and halibut, has culminated in the culmination of mariculture flounder in the world. European salmon and Senegal salmon are traditional products on the European fish market and are very popular. The current price in the EU market is 9 to 13.5 EUR/kg. The two species of fish are mainly marketed by the sea, and the European Union has tightened its quotas on fishing quotas. Therefore, it is very supportive of the large-scale commercialization of the two species of fish. The author once went to the Netherlands Fisheries Research Institute as a visiting scholar of the state for a one-year study abroad in 2003. During the study period, I participated in the research work of the European salmon breeding and breeding project. This is an EU fishery research project, and fishery scientists and fishery workers from six countries, including the Netherlands, the United Kingdom, Norway, Belgium, Greece, and Portugal, participate in the research. It is of great significance for the study of European eels to develop the eel breeding resources along the coast of China and the introduction and selection of excellent marine fish species. The following is a brief introduction of European salmon breeding and breeding research.
1 European eel breeding?
1.1 The biological profile of European eels The European Solea solea? is distributed in the North Sea and the Mediterranean, southwards to Senegal and up to Cape Verde, and its depth of habitat ranges from 0 to 150 m. It is buried in sediments or sand under the sea. . The European quail has an elliptical body with a blunt head and the dorsal fins start from the head and extend to the base of the tail shank. The maximum body length is 70cm, the maximum weight is 3kg, and the longest period of life is 27 years. Carnivorous, feeding on worms, shellfish, and small crustaceans. The Wadden Sea in the Netherlands is the main breeding ground for European cockroaches. Under normal circumstances, mature male body length 20 ~ 45cm, mature female body length is 25 ~ 60cm, distributed in fine sand, deep, warm, low salinity waters, winter swim to deep water life. ?
1.2 Breeding of European salmon
1.2.1 Spawning and hatching Broodstock management: The brooding pond is a black PE circular pool (area of ​​7m2) with a diameter of 3m. There is foam plastic around the perimeter of the pool wall, and the water body is 5m3. The black plastic sheet on the top cover of the pool is shaded. A 40W bulb is set in the center of the top and the light intensity of the light reaching the water surface is 170lx. The broodstock stocking density is 1 to 3 kg/m2. The average weight of females is about 500 g, the average weight of males is about 200 g, and the stocking ratio of males and females is roughly 1:1. During the spawning season, the brooders are fed three times a week (once every other day), one is mussel meat, and the other two are worms (Nereis virens and Arenicola marina) to fully ensure the nutrition of the broodstock during the spawning period. It is 1.5% to 2%. The non-breeding season is fed with a homemade frozen wet pellet feed consisting of cooked mussel meat, cultured salmon feed, and fish meal.
Broodstock spawning: Artificial breeding of European eels is not suitable for hormone production. It can only simulate light and temperature during the natural reproduction period to manually adjust the temperature and light, and promote their spawning. In the experiment, it was found that the sun exposure time required for European broodstock to lay eggs was 11 to 17 hours, and the temperature was 8 to 12 degrees C. As the spawning continued, the quality of fish eggs gradually increased. Spawning of females reached 333-496 g/kg body weight during reproduction.
The hatching of fish eggs: European eel eggs diameter 1.1 to 1.6mm, transparent, oil spherules, evenly distributed, 1g can contain 700 to 900 eggs, with egg production, the egg diameter gradually decreased. Fertilized eggs can hatch out at approximately 13°C for approximately 96 hours. 100L conical cones were used to incubate and incubate the fertilized eggs. The hatched seawater salinity was 32.4 ‰, and the temperature was about 13°C. Embryos were usually identified on the afternoon of the second day after spawning. ?
1.2.2 Cultivating larvae The newly hatched larvae are about 2.6 mm in length and have a yolk globules with a diameter of 1 to 1.2 mm in the abdomen. The digestive tract has not yet penetrated during the first few days of hatching to absorb the nutrients of the yolk globules. When the diameter of the yolk ball was reduced to about 0.35mm, the larvae opened their food intake. Normally, the larvae are transferred to the larval rearing system on the third to fourth days after hatching, gradually heating up to about 17-19°C. The larvae began to feed Artemia nauplii after feeding, and they were injected twice daily and the feeding density was 5 halo/mL. Four to five days after the opening of the larvae, feeding of fortified juveniles enriched with a DHA-enriched enhancer (Algamac-2000) was started. After ingestion of fortified larvae, the pigmentation of the larvae can be normalized, that is, there are pigments and patterns on the side of the eye, no pigment and pattern on the side of the eye, and avoid albino fish. At the same time as feeding the fortified Artemia, AGLO0 was started to be fed to the grain feed. After about 5 to 6 days, AGLO1 was fed to the grain feed until the larvae hatched. All feed pellets.
Experiments have proved that it is very important to effectively control the time for stopping the feeding of biological feeds. The earlier the biological feed is stopped, the greater the difference in larval body length. However, granular diets have more comprehensive nutrition for the growth and development of larvae. It is very beneficial for the growth of larvae to properly feed biofeeds earlier. ?
1.2.3 There is a metamorphosis process during larval rearing. At 17～19°C, the larvae began to metamorphose from the fourteenth day after hatching, that is to say, they migrated from plankton to life at the bottom of the volvulus, and the left eye began to move upwards. From the 18th to the 24th day after hatching, the left eye was completely Move to the right side of the body to complete the metamorphosis. ?
1.2.4 Problems to be Noted in Routine Management Pay attention to the adjustment of feeding techniques during larval rearing and start by feeding Artemia twice daily. After opening the larvae, slowly let it habitually eat pelleted food, that is, every feeding in the morning and evening is to feed the granule bait when the larvae are hungry, and then feed the Artemias after one hour. After the larva hatched, the belt feeder was installed around the 21st day, and the larvae needed to feed the food for one day and feed it automatically for 24 hours.
2 European carp adult culture?
2.1 Aquiculture facilities and methods There are 4 circular black PE breeding experiment pools in the greenhouse near the institute, with a diameter of 3m, a single pond area of ​​7m 2 and a water depth of 0.8m. The aquaculture water is controlled by a recycling system. The entire facility is very advanced. The water discharged from the fish ponds goes through physical filtration, biological filtration, and pressure aerobic processes and flows back to the aquaculture pond. The growing area bred European salmon that hatched in 2000. One of the pools has also placed a layer of stencils. The squid coverage rate on the stencils has reached 100%, effectively expanding the culture area. Since September 2003, a mushroom production facility has been experimentally installed to conduct shallow-water layer culture. This device is 21m long and 1.36m wide. It is made into a two-layer aquaculture tank (can be multi-layered), with inner waterproof lining, and inlet and outlet pipes. Connected to the recirculation system of the greenhouse to control the water flow rate with the inlet valve. Previously, key flow velocity data have been obtained in small experiments, which not only enable the salmon to fully ingest food, but also enable the leftover baits to be effectively eliminated. The advantage of this method of cultivation is that the use of shallow water multi-layered culture structure to make full use of space, utilizing the relatively small size of the water body on the flat surface of the catfish, greatly expands the culture area. ?
2.2 Management measures For squid reared in a round pond, pellet feeders are fed for 24 h each day by means of automatic spreaders. The daily feed rate is 0.5% to 2%. Daily remove residual bait and dead fish from the central discharge pipe. The maximum breeding density is 25kg/m2, and the general density is 10-20kg/m2. After about 2 to 3 years of cultivation, the largest individual of carp can reach 800g. In the shallow water layer culture structure, automatic feeding is performed with a belt feeder 24h. ?
3 questions and discussions?
3.1 It is generally believed that the high buoyancy rate of European salmon eggs is also a high fertility rate. However, in experiments, it was found that there was no relationship between the buoyancy rate and the fertilization rate of European salmon eggs. Sometimes the egg floatability is very high and the fertility rate is very low. Sometimes the float rate is low and the fertility rate is not low. Most fertilized eggs were found to be deliquescent in some batches of eggs, and the larvae hatched by these fertilized eggs were healthy.
3.2 In the initial stage of the experiment, glutaraldehyde was used to disinfect the fish eggs, but the hatching rate of the sterilized fish eggs was found to be lower. The analysis and disinfection made the egg membrane hard, which affected the hatching of the larvae. Therefore, the larvae were not sterilized after May and the hatching rate was reversed. rise.
1 European eel breeding?
1.1 The biological profile of European eels The European Solea solea? is distributed in the North Sea and the Mediterranean, southwards to Senegal and up to Cape Verde, and its depth of habitat ranges from 0 to 150 m. It is buried in sediments or sand under the sea. . The European quail has an elliptical body with a blunt head and the dorsal fins start from the head and extend to the base of the tail shank. The maximum body length is 70cm, the maximum weight is 3kg, and the longest period of life is 27 years. Carnivorous, feeding on worms, shellfish, and small crustaceans. The Wadden Sea in the Netherlands is the main breeding ground for European cockroaches. Under normal circumstances, mature male body length 20 ~ 45cm, mature female body length is 25 ~ 60cm, distributed in fine sand, deep, warm, low salinity waters, winter swim to deep water life. ?
1.2 Breeding of European salmon
1.2.1 Spawning and hatching Broodstock management: The brooding pond is a black PE circular pool (area of ​​7m2) with a diameter of 3m. There is foam plastic around the perimeter of the pool wall, and the water body is 5m3. The black plastic sheet on the top cover of the pool is shaded. A 40W bulb is set in the center of the top and the light intensity of the light reaching the water surface is 170lx. The broodstock stocking density is 1 to 3 kg/m2. The average weight of females is about 500 g, the average weight of males is about 200 g, and the stocking ratio of males and females is roughly 1:1. During the spawning season, the brooders are fed three times a week (once every other day), one is mussel meat, and the other two are worms (Nereis virens and Arenicola marina) to fully ensure the nutrition of the broodstock during the spawning period. It is 1.5% to 2%. The non-breeding season is fed with a homemade frozen wet pellet feed consisting of cooked mussel meat, cultured salmon feed, and fish meal.
Broodstock spawning: Artificial breeding of European eels is not suitable for hormone production. It can only simulate light and temperature during the natural reproduction period to manually adjust the temperature and light, and promote their spawning. In the experiment, it was found that the sun exposure time required for European broodstock to lay eggs was 11 to 17 hours, and the temperature was 8 to 12 degrees C. As the spawning continued, the quality of fish eggs gradually increased. Spawning of females reached 333-496 g/kg body weight during reproduction.
The hatching of fish eggs: European eel eggs diameter 1.1 to 1.6mm, transparent, oil spherules, evenly distributed, 1g can contain 700 to 900 eggs, with egg production, the egg diameter gradually decreased. Fertilized eggs can hatch out at approximately 13°C for approximately 96 hours. 100L conical cones were used to incubate and incubate the fertilized eggs. The hatched seawater salinity was 32.4 ‰, and the temperature was about 13°C. Embryos were usually identified on the afternoon of the second day after spawning. ?
1.2.2 Cultivating larvae The newly hatched larvae are about 2.6 mm in length and have a yolk globules with a diameter of 1 to 1.2 mm in the abdomen. The digestive tract has not yet penetrated during the first few days of hatching to absorb the nutrients of the yolk globules. When the diameter of the yolk ball was reduced to about 0.35mm, the larvae opened their food intake. Normally, the larvae are transferred to the larval rearing system on the third to fourth days after hatching, gradually heating up to about 17-19°C. The larvae began to feed Artemia nauplii after feeding, and they were injected twice daily and the feeding density was 5 halo/mL. Four to five days after the opening of the larvae, feeding of fortified juveniles enriched with a DHA-enriched enhancer (Algamac-2000) was started. After ingestion of fortified larvae, the pigmentation of the larvae can be normalized, that is, there are pigments and patterns on the side of the eye, no pigment and pattern on the side of the eye, and avoid albino fish. At the same time as feeding the fortified Artemia, AGLO0 was started to be fed to the grain feed. After about 5 to 6 days, AGLO1 was fed to the grain feed until the larvae hatched. All feed pellets.
Experiments have proved that it is very important to effectively control the time for stopping the feeding of biological feeds. The earlier the biological feed is stopped, the greater the difference in larval body length. However, granular diets have more comprehensive nutrition for the growth and development of larvae. It is very beneficial for the growth of larvae to properly feed biofeeds earlier. ?
1.2.3 There is a metamorphosis process during larval rearing. At 17～19°C, the larvae began to metamorphose from the fourteenth day after hatching, that is to say, they migrated from plankton to life at the bottom of the volvulus, and the left eye began to move upwards. From the 18th to the 24th day after hatching, the left eye was completely Move to the right side of the body to complete the metamorphosis. ?
1.2.4 Problems to be Noted in Routine Management Pay attention to the adjustment of feeding techniques during larval rearing and start by feeding Artemia twice daily. After opening the larvae, slowly let it habitually eat pelleted food, that is, every feeding in the morning and evening is to feed the granule bait when the larvae are hungry, and then feed the Artemias after one hour. After the larva hatched, the belt feeder was installed around the 21st day, and the larvae needed to feed the food for one day and feed it automatically for 24 hours.
2 European carp adult culture?
2.1 Aquiculture facilities and methods There are 4 circular black PE breeding experiment pools in the greenhouse near the institute, with a diameter of 3m, a single pond area of ​​7m 2 and a water depth of 0.8m. The aquaculture water is controlled by a recycling system. The entire facility is very advanced. The water discharged from the fish ponds goes through physical filtration, biological filtration, and pressure aerobic processes and flows back to the aquaculture pond. The growing area bred European salmon that hatched in 2000. One of the pools has also placed a layer of stencils. The squid coverage rate on the stencils has reached 100%, effectively expanding the culture area. Since September 2003, a mushroom production facility has been experimentally installed to conduct shallow-water layer culture. This device is 21m long and 1.36m wide. It is made into a two-layer aquaculture tank (can be multi-layered), with inner waterproof lining, and inlet and outlet pipes. Connected to the recirculation system of the greenhouse to control the water flow rate with the inlet valve. Previously, key flow velocity data have been obtained in small experiments, which not only enable the salmon to fully ingest food, but also enable the leftover baits to be effectively eliminated. The advantage of this method of cultivation is that the use of shallow water multi-layered culture structure to make full use of space, utilizing the relatively small size of the water body on the flat surface of the catfish, greatly expands the culture area. ?
2.2 Management measures For squid reared in a round pond, pellet feeders are fed for 24 h each day by means of automatic spreaders. The daily feed rate is 0.5% to 2%. Daily remove residual bait and dead fish from the central discharge pipe. The maximum breeding density is 25kg/m2, and the general density is 10-20kg/m2. After about 2 to 3 years of cultivation, the largest individual of carp can reach 800g. In the shallow water layer culture structure, automatic feeding is performed with a belt feeder 24h. ?
3 questions and discussions?
3.1 It is generally believed that the high buoyancy rate of European salmon eggs is also a high fertility rate. However, in experiments, it was found that there was no relationship between the buoyancy rate and the fertilization rate of European salmon eggs. Sometimes the egg floatability is very high and the fertility rate is very low. Sometimes the float rate is low and the fertility rate is not low. Most fertilized eggs were found to be deliquescent in some batches of eggs, and the larvae hatched by these fertilized eggs were healthy.
3.2 In the initial stage of the experiment, glutaraldehyde was used to disinfect the fish eggs, but the hatching rate of the sterilized fish eggs was found to be lower. The analysis and disinfection made the egg membrane hard, which affected the hatching of the larvae. Therefore, the larvae were not sterilized after May and the hatching rate was reversed. rise.
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