International Journal of Aquaculture, 2025, Vol.15, No.6, 298-307 http://www.aquapublisher.com/index.php/ija 302 according to their body weight, and the dose of male fish is about half of that of female fish. The male and female ratio is 1:1 to ensure that they enter the breeding state at the same time. Oxygen injection is often performed in the evening, and the broodstock group can be seen spawning at dawn the next day. At the same time, combined with water temperature adjustment and a small amount of micro-flow water stimulation, simulating natural reproduction signals can improve the labor-inducing effect. Standardized hormone induction significantly improves the efficiency of artificial reproduction (Hettiarachchi et al., 2024), especially for fish groups that are difficult to spawn at the same time under natural conditions, ensuring the stability of seed production and the safety of broodstock. 5.2 Artificial insemination and embryo incubation management Artificial insemination is usually performed after induction of labor when the female is about to ovulate. Technicians gently press the abdomen of the female fish to collect the eggs, and squeeze out the semen of the male fish and mix them well to achieve in vitro fertilization. Since yellow bream eggs are sticky, it is necessary to add an appropriate amount of clay suspension or tannic acid solution and stir gently after fertilization to remove the egg stickiness (deadhesiveness) and prevent the eggs from adhering to each other and affecting water flow and development. The fertilized eggs after debonding are placed in incubation equipment for running water incubation management. During the incubation process, maintain appropriate water temperature (such as 18 C~25 °C, the embryo hatches in about 7 days at around 20 °C), sufficient dissolved oxygen and micro-flowing water to ensure normal development of the embryo. White necrotic eggs should be removed regularly and fungal infections such as saprolegnia should be prevented (the eggs can be soaked with light salt water or safe antifungal agents). When the embryo develops to the point where the yolk sac has been absorbed and the fry begin to swim for food, they need to be transferred to the seed breeding tank for feeding and management in time (Hettiarachchi et al., 2024). Perfect artificial insemination and hatching management can significantly improve the fertilization rate and seedling survival rate. 5.3 Case study: commercial practice of artificial breeding in yellow catfish The artificial breeding of yellow catfish is not a recent development, but it is only in recent years that there have been more and more cases that have become large-scale and profitable. A typical example is the catfish breeding farm in hunan. The technical team there did not have a smooth start. They repeatedly explored in the processes of broodstock breeding, spawning and hatching, and gradually developed a more efficient management approach. Over the course of a breeding season, through hormone induction and meticulous operation, they produced four batches of yellow catfish parent fish in just one week, hatching nearly 40 million healthy fry. It seems to be just a number, but behind it is the support of a full-process system, from the overwintering management of broodstock, to simultaneous induction of labor and flow hatching during the breeding season, and then to the grading and cultivation of seedlings, each link is interlinked. This approach ensures a high survival rate of the fish fry and their rapid growth. The result is that artificial breeding not only makes up for the shortage of wild seedlings but also makes the supply of seedlings more stable, and the income of farmers has also increased in a tangible way (Figure 1). Now, the promotion of artificial breeding of yellow catfish is driving the entire industry towards a larger scale and more sustainable direction (Hettiarachchi et al., 2024). 6 Reproductive Behavior and Environmental Adaptation Mechanisms 6.1 Spawning behavior characteristics in natural environments The breeding behavior of yellow catfish in natural waters is obviously seasonal and gregarious. Generally, wild yellow catfish reaches sexual maturity at the age of 2 winter, and enters the breeding period in late spring and early summer every year when the water temperature rises to about 20 °C. They often choose the time after rain when the water level rises and the environment is fresh to swim in groups to shallow areas with aquatic plants and gravel along the rivers and lakes. During the breeding process, several male fish chase and surround the female, stimulating the female to release eggs and at the same time expel sperm to complete in vitro fertilization. yellow catfish eggs are sticky and adhere to the surface of aquatic plants and rocks after they are laid to obtain good oxygen supply (Liao et al., 2018). After spawning, the broodstock does not protect the eggs, and the eggs develop
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