International Journal of Aquaculture, 2025, Vol.15, No.6, 298-307 http://www.aquapublisher.com/index.php/ija 299 ecological management of species-specific responses must be considered (Liao et al., 2018). However, innovations in breeding technology are opening up a new situation. Whether it is gene editing, marker-assisted selection, or the breeding of YY super male lines, they all provide new ideas for improving growth performance, disease resistance and reproductive efficiency. Therefore, a thorough understanding of the reproductive biology of yellow catfish is not merely a matter of academic interest, but also concerns the sustainable development of the industry. This article compiles the major progress in the research on the breeding and ecology of yellow catfish in recent years, explores how these achievements can feed back to aquaculture practice, and points out the research directions worthy of attention in the future. From multiple perspectives including molecular genetics, physiology and ecology, we attempt to explain how this knowledge can help improve breeding, disease prevention and control, and production strategies. Ultimately, the continuous exploration of this field can not only enhance the efficiency and stability of breeding, but also provide scientific support for the protection and restoration of wild populations under environmental changes. 2 Anatomy and Developmental Patterns of the Reproductive System in Yellow Catfish 2.1 Structural differences between male and female reproductive systems The internal structural differences between male and female Pelteobagrus fulvidraco are quite obvious, which is also an unavoidable point when studying its reproductive strategies and breeding management. The ovaries in female fish are mostly cylindrical, while the testicles in male fish are like forked branches. The gender can be identified at a glance during dissection (Liao et al., 2018). Female ovaries are distributed in pairs. From immature to fully mature, they roughly go through six stages. The size and appearance of oocytes can directly reflect the development process. On the male side, the paired testicles gradually become active before reproduction. The spermatogenic cells inside start to divide in large numbers, and spermatogenic cysts increase and mature sperm are produced (Jing et al., 2014). Later, with the breakthrough of molecular genetics technology, people successfully cultivated YY super males, providing new materials for the study of gonadal development. Tissue sections showed that these YY males had a more developed testicular structure, larger spermatogenic cysts, and a higher sperm count, indicating that genetic background does influence the maturity and functional performance of the gonads (Gong et al., 2018). 2.2 Temporal changes in the reproductive cycle When the yellow catfish reproduces is not a fixed death but varies with environmental changes. In flowing water, they generally lay eggs earlier than the populations in still water, seemingly an adaptation to local conditions such as water flow and temperature. Factors such as temperature, duration of light exposure and water quality can also unconsciously affect the development process of the gonads. The maturity of female fish ovaries, the number of eggs laid and the size of the eggs fluctuate with different environments and habitats. Before the spawning season of male fish, spermatocytes in the testis begin to multiply in large numbers, and mature sperm gradually accumulate (Jing et al., 2014; Liao et al., 2018). However, there are exceptions. During the critical stage of sex differentiation, if high-temperature stress is encountered, gonadal development will be disrupted, the sex ratio will shift, and reproductive capacity will decline. This is particularly worthy of attention in the context of increasingly intensified climate change (Chen et al., 2022). These periodic changes remind us that both environmental and genetic factors jointly determine the breeding rhythm of the yellow catfish, and mastering this rhythm is a crucial part of aquaculture management. 2.3 Relationship between sex ratio and reproductive success rate Whether the population of yellow catfish can reproduce smoothly depends on the sex ratio. The gender ratio varies in different regions and water bodies, and is often affected by environmental conditions such as temperature and water flow. In fish farms, people tend to favor male fish because they grow fast and are large in size. Therefore, all-male or male-biased populations are often obtained through sex reversal or by breeding YY super males (Jing et al., 2014; Gong et al., 2018). But this is not an absolute good thing either. Environmental stress
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