As a unique species, the growth rate of seven-gill eels during their larval stage is influenced by environmental food availability, which in turn determines the dynamic adjustment of their sex ratio. This study focuses on the profound impact of this mechanism on complex ecosystems. The research first established a differential equation model reflecting the relationship between sex ratio and population size. Simulations revealed that when food scarcity causes the male proportion to rise significantly to 78%, the population’s demand for resources changes accordingly. Subsequently, a population competition model was used to analyze the survival competitive advantages of seven-gill eels under different resource conditions. Furthermore, the Lotka-Volterra model was employed to quantitatively examine how population fluctuations caused by shifts in sex ratios affect the balance of predator-prey relationships within the food chain. The study further expanded its perspective to include mutualistic and parasitic relationships between species, simulating how changes in population size under the regulation of the seven-gill eel’s sex ratio provide survival and nutritional advantages to other participants in the ecosystem. Finally, sensitivity analysis was used to verify the critical role of survival parameters in the competitive model for system evolution. This study demonstrates that by regulating sex ratios, the seven-gill eel not only optimizes its own survival and reproduction in resource-limited environments but also profoundly alters the steady state of the entire ecosystem through complex interspecific interactions.
