Artificial fry breeding generally follows pro-shellfish harvesting and selection, promoted ripening, oxytocin production (inducing production), insemination, egg washing, early hatching, early larval breeding, laying seedlings, juveniles out of the pool and daily water quality monitoring. For example, the Hebei Provincial Fisheries Research Institute conducted a trial of artificial breeding of miracidia from 1977 to 1978. The method was:
(1) Inducing production: Intimate harvesting is used to harvest oysters in natural mature areas during the maturation season. The intimate will be washed before placing it in urine, and it will stand still. When the two shells open, they will wedge in time and use the syringe to the base of the foot. Pierce the gonads and slowly inject 0.2-0.3 ml of aqueous ammonia solution at a concentration of 2 Torr into the water bath. Then place the hair lice in the water tank to stimulate the water flow. Use a suitable hose to gently inject the fresh filtered seawater until the tank is full of water. About a minute or so, the water is discharged again by the siphon method, and the water in the tank can still be immersed in the carcass, and it is re-injected after an interval of about 10 minutes. This repeats until spawning and ejaculation.
(2) Collection and treatment of refined and coexisting eggs: When females lay a large number of eggs, remove the males, collect the eggs produced, dilute them with filtered seawater, and filter them with microporous sieves to remove impurities. .
(3) Fertilization and egg washing: dilute the filtered egg fluid and add appropriate amount of semen to gently agitate. After the sperm and egg is mixed for 10 minutes, the fertilized egg can gradually sink and the polar body appears, ie the egg is washed, and the egg is washed out by siphon method. A mixture of superfluous sperm and unfertilized eggs is then added to the filtered seawater immediately to allow the fertilized egg to subside and drain again. The fertilized egg usually undergoes 4-5 washings during the embryonic development stage until a large number of larvae are bred. Float up.
(4) Juvenile culture: Generally, the water temperature is controlled at 23-27°C, the specific gravity is 1.018-1.020, the PH value is 8.2-8.4, and the water can also be stirred appropriately. The fresh seawater is added 1-2 times per day, each time 1/4 When left and right, when the later stage larvae are slightly larger, the water can be filtered out with a sieve less than the shell, and fresh filtered seawater can be added. When entering the D-shaped larvae, the intake of outside feed should be started in a timely manner. The new moon diamond-shaped algae and flat algae, and then gradually add Chaetoceros, so that the larvae are constantly metamorphosis, grow up.
Artificial proliferation of benthic camp benthic life, activity is weak, can only be a short distance crawling, can live in the original sea area all year round, adapt to changes in the conditions of the sea is strong, the proliferation of frizz, generally in a certain water area, to take artificial Measures to create conditions suitable for the propagation and growth of raccoon hairpins, and increase the amount of resources, such as sea closures, improved environmental conditions, pro-shellworm transplantation, artificial hatching and other measures. Domestically, for the proliferation of pilaris, the pro-bezoar transfer method is generally adopted to increase the amount of edgy resources. For example, in Hebei province, 50,000 kilograms of raccoon was put into Qinhuangdao Bay in 1964. After about 10 years, the water area with only a small amount of raccoon distribution has become single. Nearly ten thousand kilograms of small-sized raccoon fisheries with a daily output of nearly 10,000 kilograms. In November of 1980, in Tianjin, in the north of latitude 3840′-3858′ and west of longitude 118, a shell of 2-2.5 centimeters high was released at a density of 0.1 kilograms per square meter. t, and delineate north latitude 3840′-3910′, the western sea area of ​​east longitude 118 is the Maodan breeding reserve, among which the north latitude 3840-′-3858′ is the raccoon breeding area. Although no detailed resource survey has been conducted afterwards, according to the production unit, this In a multi-proliferation sea area, the number of young cubs has increased significantly, and the production of plovers is not strong. There is no need for specific management. As long as some strict administrative measures are taken, the purpose of multiplication of resources can be achieved.
Protection measures (1) Qualified catching specifications: Fleecy cricket generally grows faster in the initial stage, and thereafter, the growth rate decreases year after year as the age grows. Therefore, in the slow growth, but also reached the stage of sexual maturation, is a more reasonable acquisition specifications, fishery departments around the determination of the smallest shell length of 3 centimeters as the catchable specifications. In order to prevent the collection of large numbers of young pups, the size of the mesh should not be limited to less than 3 cm in order to achieve the goal of catching large and small objects and protecting resources.
(2) Limitation of hunting time: In order to promote the breeding of offspring of raccoon larvae and to exert the maximum effect of the propagation period, it is generally not to be caught during the breeding period and rapid growth period of the raccoon raccoon. Therefore, in the administration of fisheries, a deadline may be determined as prohibition of mining. During the arrest period, it is used to protect and proliferate resources.
(3) Limiting the number of catches: Formulating a reasonable number of catches is one of the important means to prevent the depletion of resources. To this end, it is necessary to effectively control the number of harvested furrows on the basis of the furry resource survey to prevent unplanned and excessive overfishing. Destroy resources.
(1) Inducing production: Intimate harvesting is used to harvest oysters in natural mature areas during the maturation season. The intimate will be washed before placing it in urine, and it will stand still. When the two shells open, they will wedge in time and use the syringe to the base of the foot. Pierce the gonads and slowly inject 0.2-0.3 ml of aqueous ammonia solution at a concentration of 2 Torr into the water bath. Then place the hair lice in the water tank to stimulate the water flow. Use a suitable hose to gently inject the fresh filtered seawater until the tank is full of water. About a minute or so, the water is discharged again by the siphon method, and the water in the tank can still be immersed in the carcass, and it is re-injected after an interval of about 10 minutes. This repeats until spawning and ejaculation.
(2) Collection and treatment of refined and coexisting eggs: When females lay a large number of eggs, remove the males, collect the eggs produced, dilute them with filtered seawater, and filter them with microporous sieves to remove impurities. .
(3) Fertilization and egg washing: dilute the filtered egg fluid and add appropriate amount of semen to gently agitate. After the sperm and egg is mixed for 10 minutes, the fertilized egg can gradually sink and the polar body appears, ie the egg is washed, and the egg is washed out by siphon method. A mixture of superfluous sperm and unfertilized eggs is then added to the filtered seawater immediately to allow the fertilized egg to subside and drain again. The fertilized egg usually undergoes 4-5 washings during the embryonic development stage until a large number of larvae are bred. Float up.
(4) Juvenile culture: Generally, the water temperature is controlled at 23-27°C, the specific gravity is 1.018-1.020, the PH value is 8.2-8.4, and the water can also be stirred appropriately. The fresh seawater is added 1-2 times per day, each time 1/4 When left and right, when the later stage larvae are slightly larger, the water can be filtered out with a sieve less than the shell, and fresh filtered seawater can be added. When entering the D-shaped larvae, the intake of outside feed should be started in a timely manner. The new moon diamond-shaped algae and flat algae, and then gradually add Chaetoceros, so that the larvae are constantly metamorphosis, grow up.
Artificial proliferation of benthic camp benthic life, activity is weak, can only be a short distance crawling, can live in the original sea area all year round, adapt to changes in the conditions of the sea is strong, the proliferation of frizz, generally in a certain water area, to take artificial Measures to create conditions suitable for the propagation and growth of raccoon hairpins, and increase the amount of resources, such as sea closures, improved environmental conditions, pro-shellworm transplantation, artificial hatching and other measures. Domestically, for the proliferation of pilaris, the pro-bezoar transfer method is generally adopted to increase the amount of edgy resources. For example, in Hebei province, 50,000 kilograms of raccoon was put into Qinhuangdao Bay in 1964. After about 10 years, the water area with only a small amount of raccoon distribution has become single. Nearly ten thousand kilograms of small-sized raccoon fisheries with a daily output of nearly 10,000 kilograms. In November of 1980, in Tianjin, in the north of latitude 3840′-3858′ and west of longitude 118, a shell of 2-2.5 centimeters high was released at a density of 0.1 kilograms per square meter. t, and delineate north latitude 3840′-3910′, the western sea area of ​​east longitude 118 is the Maodan breeding reserve, among which the north latitude 3840-′-3858′ is the raccoon breeding area. Although no detailed resource survey has been conducted afterwards, according to the production unit, this In a multi-proliferation sea area, the number of young cubs has increased significantly, and the production of plovers is not strong. There is no need for specific management. As long as some strict administrative measures are taken, the purpose of multiplication of resources can be achieved.
Protection measures (1) Qualified catching specifications: Fleecy cricket generally grows faster in the initial stage, and thereafter, the growth rate decreases year after year as the age grows. Therefore, in the slow growth, but also reached the stage of sexual maturation, is a more reasonable acquisition specifications, fishery departments around the determination of the smallest shell length of 3 centimeters as the catchable specifications. In order to prevent the collection of large numbers of young pups, the size of the mesh should not be limited to less than 3 cm in order to achieve the goal of catching large and small objects and protecting resources.
(2) Limitation of hunting time: In order to promote the breeding of offspring of raccoon larvae and to exert the maximum effect of the propagation period, it is generally not to be caught during the breeding period and rapid growth period of the raccoon raccoon. Therefore, in the administration of fisheries, a deadline may be determined as prohibition of mining. During the arrest period, it is used to protect and proliferate resources.
(3) Limiting the number of catches: Formulating a reasonable number of catches is one of the important means to prevent the depletion of resources. To this end, it is necessary to effectively control the number of harvested furrows on the basis of the furry resource survey to prevent unplanned and excessive overfishing. Destroy resources.