Technical measures to reduce the death of spawning parent fish

Reducing the death of spawning parent fish is an important technical work in fry culture. There are two main factors causing the death of spawning parent fish: one is that the parent fish consumes a lot of energy during spawning and reproduction, which increases the side effects of spawning drugs and reduces the resistance of parent fish. If the fish is seriously injured, various pathogens will take the opportunity to infect the fish and cause diseases, resulting in the death of parent fish; The other is that the parent fish's constitution is poor, or the water temperature changes greatly when the spawning occurs, and the dosage of the spawning drug is improper (too high or too low), the parent fish can not lay eggs normally or have dystocia, and thus cause its own physiological activity disorder and death. Therefore, it is necessary to focus on prenatal cultivation and postnatal care of parent fish. In addition to the prenatal breeding of parent fish, so that parent fish have a strong physique, first of all, we should pay attention to fishing operations, which is an important part of reducing parent fish casualties. Whether you are catching parent fish in the parent fish pond or in the spawning pool, you should pull the net quickly and harmoniously. As soon as the net is close to the shore, quickly pull the parent fish out of the pool wall after setting up the net, so as to avoid the parent fish colliding with the pool wall and getting injured. When the temperature is high in sunny days and the distance of fish transportation (the distance between the parent fish pond and the spawning pond) is long, it is best to fish in the early morning or evening to prevent the parent fish from being suffocated in the canvas stretcher. To select a good physique and appropriate gonad maturity of the parent fish induced labor, do not use high doses of drugs induced labor. Secondly, when pulling the spawning parent fish from the spawning pool, check them one by one. For female parent fish with enlarged abdomen, gently press their abdomen with hands to help them produce mature eggs in their abdomen; if the female parent fish has dystocia caused by blocked reproductive pores, use sterilized surgical scissors to cut open and expand the blocked reproductive pores to allow mature eggs to be discharged from the body. In this way, mature eggs can be prevented from absorbing water and swelling in the parent fish and endangering the parent fish (this is the main cause of female parent fish death). For parent fish with body surface injury, dry the wound with absorbent cotton first, then wash it with potassium permanganate solution or malachite green solution containing 1% salt, and then apply iodine (iodine tincture) to the wound from the tail to the reverse scale of the head with fingers, and then apply ointment. After spawning, parent fish, whether injured or not, were injected with appropriate doses of anti-inflammatory and anti-disease drugs according to their body weight. After breeding spawning parent fish pond, need to use quicklime clear pond disinfection, pool water to fresh, water depth to 1.5 meters or so is appropriate, in the first month of postpartum parent fish into the pool had better not apply organic fertilizer, and regularly with bleaching powder, strong chlorine essence or fish and shrimp safety and other drugs disinfection sterilization, prevention and control of fish disease. The parent fish will be fed about 5 days after entering the pond, mainly feeding the rice sprouts, malt, bran cake or compound feed that the parent fish likes to eat, and feeding the grass parent fish with appropriate fresh grass. Generally, a small amount of new water is replaced in 3~5 days to regulate the water quality in the pool, stimulate the appetite of the parent fish, make it recover quickly, and enhance disease resistance.